you are clamping too long

this is the only product covered in this video. buy it if you like.lol: amzn.to/3ZNMoLR
Check my amazon storefront for tools I commonly use in my shop: www.amazon.com...
_____________________
I helped Scott test common wood joinery strength you can see here: • This Simple Joint is S...
_____________________
My favorite [small] woodworking tools:
General Saw - Japanese Gyokucho Pull Saw - amzn.to/3x30bhW
Dovetail Saw - Japanese Dozuki Pull Saw - amzn.to/3v5imlL
Japanese Plane- Kanna (65mm)- amzn.to/3irvyi0
Japanese Plane - Kanna (40mm) - amzn.to/3w3WPLA
Chisel hammer - Japanese Chisel Hammer- amzn.to/3z8TzjT
Mallet - Wood Is Good Mallet - amzn.to/34ViZUq
Square Ruler - Starrett Combination Square (steel head) - amzn.to/3imGX2N
Marking Ruler - Incra Precision T-Rule - amzn.to/3cnrQ59
Caliper - iGaging 6" Caliper - amzn.to/3pxRyJM
Mechanical Pencil - Rotring 600 - amzn.to/3x6jJ53

[@worstworkshop]

Great video!! Here's my theory. When the clamps were removed after 30 minutes, the glue hadn't cured enough to compensate for the release of pressure. The boards pulled apart just a little bit on their own and messed up the glue. When you just pushed the boards together and left them, there was no change after 30 minutes, so the joint was stronger. Maybe?

[@robbyflair3552]

Was thinking the same thing

[@whyfckwithmedamu6073]

Hadn’t read your reply before my post, totally agree.

[@JustinShands]

Agreed, to look at it another way, the clamps squeeze out far more glue than the "hand pressed" version, so when the pressure relaxes to "clampless", there is less glue in the joint than the hand pressed version, but a wider gap than the long-term clamped version.

[@michaelhenderson4706]

Yep. My thought as well. Don't know for certain, but glad to be part of the majority consensus hah

[@ehisey]

Not even a question. The glue has not fully cured in less than 24 hours. It achieves a minimum working strength in 30 minutes.

[@FlyingMoose_]

I was a research engineer for 10 years designing and carrying out experiments, and a woodworker since before that. This is one of the most complete and robust scientific woodworking experiment videos I've seen. Controlling for all sorts of variables via sensors that most others would ignore. Thank you for this video, I and countless others will benefit from your rigor! I'm about to glue up a large table in half a dozen glue ups and this will save me days!!

[@WoodcraftBySuman]

Thanks dude! I could have added more variables like letting each of the conditions dry 24hrs but it takes so much material and time to do this experiment as-is. I’m glad you appreciate the consideration that went into the setup.

[@FlyingMoose_]

@@WoodcraftBySuman There are always more variables! You seem proficient at identifying and appropriately accounting for the important ones to reach practical, useful conslusions which is what makes good science. Most videos like yours are woodworkers taking a stab at being scientists, with varying success. You strike me as a scientist first, applying yourself to woodworking. Do you have a background in research?

[@WoodcraftBySuman]

@@FlyingMoose_ haha. Pretty solid deductions there. Yes I am a scientist - though in biologics.

[@FlyingMoose_]

@@WoodcraftBySuman Not a lot of fields that have a future in research beyond academia, biologics seems like it would be a good one. I worked in metal product manufacturing research and applications. Very large lab with lots of fabrication, inspection and data collection equipment - lots of work with load cells, they are so incredibly valuable for experiments but unfortunately very expensive! Stuff I've always dreamed of applying to woodworking so your videos resonate strongly with me, I'll be binging them over the next few days.

[@WoodcraftBySuman]

@@FlyingMoose_ that’s super cool! And hope you like the videos. I only have a few on testing stuff as this has been a recent pivot for the channel. I will continue to make testing or testing adjacent videos going forward.

[@DKWalser]

I worked in a furniture mill in the early 1980's. When making raised panel doors with standard stick and cope construction, our rule was to leave the doors in the clamps for at least 2 hours. After that time, they could be removed from the clamps and stacked if we needed the clamps for another batch of doors. (We typically made doors in batches of 50 to 100 doors.) We were using a typical PVA glue, something similar to Titebond Original, which we bought in 55 gallon drums. We let the doors cure for approximately 24 hours before doing any additional work on the doors (trimming to final width and length, putting an edge profile on them, sanding, etc.). I follow the same practice in my shop today. I leave a glue-up in the clamps for at least 2 hours and don't stress the joints for about 24 hours. I've never had a glue joint fail when following these procedures. (Except for the time at the Furniture Mill when someone stored a 55 gallon drum of glue outside, overnight, in sub-zero temps. None of the joints made with that glue held! PVA glue is ruined by freezing.)

[@mlindholm]

Ruined by freezing, eh? Guess I should be throwing away all the bottles that sat in the garage over the winter and experienced repeated freeze thaw cycles. Not a lot of glue, but a couple of small bottles from when I couldn't find the last one and just bought new.

[@1495978707]

Could be that the glue was still cold when applied

[@DKWalser]

No. We confirmed with our supplier that freezing ruins PVA glue. If your glue freezes, simply throw it away. There’s nothing that can be done to make it work after that.

[@msk3905]

Dang iI ust glued up a bunch of things with my titebond that was stored in my non heated garage. Great now I have to find a new spot to store my glue.

[@shinnick22]

I can attest that frozen wood glue does not work that well after thawing. I’ve also accidentally let CA glue freeze and that stuff is worthless after that

[@weldabar]

Great info. I think one important point was unstated or understated: the piece without clamps was not disturbed. We saw how little force was required to break the joints when the glue had not dried yet. Clamps hold the pieces together so that they don't come apart from something as minor as bumping the table that the glued pieces are on. Edit after watching again: the proper testing would have been to clamp for 1, 4, and 12 hours - then waiting to test until the glue had cured at 24 hours. While 30 minutes was shown to be too little, it was not shown what happens at 1, 4, or 12 hours. The assumption that 4 hours is enough is merely assumed.

[@WoodcraftBySuman]

I agree with you that a second subset of 1hr, 4hr, and 12 hr clamp time with full 24hr cure would have added better data for consideration on this video. Two reasons why I did not do that: 1) it makes the video longer and slightly more complicated to follow. I have to consider average view duration and retention times when making videos on youtube. 2) it would take a lot more wood and I felt bad wasting so much wood as-is. Because 4hrs is able to get strength that competes with the strength of the fibers itself, it is a reasonable conclusion to make that 4hr clamp time generates strong enough joint to remove clamps at room temps and 200psi. Tests like this are just that: tests. How I chose to break the joints is not necessarily analogous real world conditions. Some people glue up in 65F shops and others in 85F shops -- this will have a huge impact on clamp time needs. There are certainly other ways to test this topic and I may even explore it in future videos. Thanks for watching.

[@weldabar]

@@WoodcraftBySuman Thank you for your tests. They are not only entertaining, but do give us more data.

[@lennart637]

Jupp, this is how it should haven been tested. No need to leave a glue up for 12-24hours in the clamps. Clamp for 2-4 hours and let the glue dry for 24 hours before applying thr full expected load. Assembly can continue after the 2-4 hours, if you don't stress the glue line to much.

[@Bob_Adkins]

When you get to the point where the wood fails instead of the glue, that's all the testing you need.

[@PeterBaumgart1a]

@@WoodcraftBySuman I can see that work and time and material has to be finite and you have to stop at some point. However your argument about "viewer retention" is unfortunate. Good methodology is like good workmanship quality: A bit of a pain to follow through with, but viewer retention through reputation is worth much more IMO. Compare for example to "Project Farm" testing. Always super meticulous. And look where it got him! (Just speak faster and edit more? 😁)

[@blaster-zy7xx]

My rule of thumb from a practical and time efficient standpoint was to clamp up in the evening and let dry overnight then release and carry on the next morning. Has worked for me for decades.

[@RAREFORMDESIGNS]

That's the overall best way to do it.

[@sickwilly1171]

I try and plan my glue ups the same way.

[@wilhelmtaylor9863]

As a mechanical engineer I applaud your approach and execution. As a long time wood worker I just found the answer to a question I have wondered about for 50 years. Congratulation, Suman, you deserve a big thanks.

[@somebodypeculiar]

Testing that actually uses multiple samples and throws out the top and bottom? Here on KZbin? Amazing! Seriously, I find it so refreshing to see a real effort to apply the scientific method. Thank you! (I've wanted countless woodworking videos here, but this is the first of yours. I subscribed.)

[@waterslethe]

Do you have a reference for where the "throw out max and min, average the rest" approach comes from?

[@somebodypeculiar]

That is a pretty common approach to doing simple statistics. The idea behind throwing out the extremes is to remove the cases where something unusual happened, letting you focus in on the most common examples. When I googled it I mostly got examples of how to do it using tools used for such analysis (Excel spreadsheets, MATLAB) rather than WHY. Which supports the idea that it is common, since so many questions about how to automate it have been asked.

[@waterslethe]

@@somebodypeculiar Thanks for looking into it! That's also what I found. I was hoping there was some statistical rule of thumb that outlined the why. To me, it seems like just lopping off the top and bottom gives an artificially high confidence in your data's consistency. I'm not good at statistics though, so that's why I ask.

[@somebodypeculiar]

Actually, removing the extremes is often a sign of a lack of confidence in the quality of the data. Measurements that are way off from the rest can be the result of a bad measurement. Or they can represent failure of an experimenter to repeat the process consistently. It is a rough-and-ready approach to trying to reach a good rule-of-thumb, rather than a rigorous statistical process. For that matter, the average (mean) isn't always the best measure to use; the median is often preferred, where half the samples are above that point and half below. Note that while the drop-on-from-each-end approach can change the average, it can not change the median.

[@waterslethe]

@@somebodypeculiar So it's like a quick and dirty way to try to limit the influence of outliers without having to actually know how to identify true outliers. I think I understand why people use it better now, thank you.

[@justincoombs9048]

For the 30 min clamp 24h dry --> The wood changed shape after unclamping, but the bond was not compete. The wood applied a separating force that the glue could not expand to fill. This is partially driven by the moisture from the glue entering the wood.

[@embracethesuck1041]

I would bet the weakness of the 30min clamp could be due to squeezing out the glue and then, before it's adequately set, rebounding the wood and creating small voids that would have remained either filled with glue in an unclamped setting or allowed to fully bond with a longer clamp time.

[@crashkg]

Love your scientific approach to woodworking. We need more channels like yours. Great info with practical uses. Thanks for your content.

[@CDI-WW]

I'm glad that I can safely free up my clamps in shorter intervals, since I started woodworking I'd usually leave glue-ups for 8 hours. Great video! The pacing of information throughout was perfect.

[@acerjuglans383]

I'm a cabinetmaker. When I was an apprentice, and going to trade school, I was taught that a properly glued joint (not too much glue, not too little) needs to be in the clamps for at least 10 minutes. And properly clamped of course. So not too much force, where you're squeezing all the glue out, and not too little force, where it's not even doing anything. In practice, I like to keep clamps on at least one hour. If it's something big and complicated, I leave it overnight. It's also important to note that regular white PVA glue is perfectly strong enough to use for furniture, as long as the joints are put together as I've described. Yellow glue, or "carpenter's" glue, also known as aliphatic resin, is typically a stronger adhesive, as it's meant for structural purposes. Titebond III is an exterior PVA, but I've noticed it is thinner and runnier than regular PVA, and it definitely needs more than 10 minutes in clamps.

[@henreh99]

Great vid, I’m sure this will be very useful and informative to a lot of people including myself! My totally unscientific thought on the 30 min/24 hour surprise breakage is that maybe it could be that when the pressure is released before the glue is fully cured, the wood slightly ‘rebounds’ when the clamp is removed and causes a sudden shift in force that might upset the bond, whereas an even pressure scheme for the entire cure time wouldn’t experience such disturbance in the forces and glue line. Just a thought for future vids - it would be nice to have a text layover of the test conditions (clamp time etc) during the part of the video where the breakages occur in the testing. Good for easily distracted people like myself to see where we’re at. Keep up the great work, I love this channel!

[@ThiNguyen-rx2iu]

I agree, in fact releasing multiple clamps one by one causes serious unbalanced pressure on the joint line.

[@MADMANmakes]

I came here to say the same thing. This absolutely what happened.

[@andyoliver539]

+1

[@tc8135]

+2

[@ReconstructingEmily]

I am so glad you did the hand test, because I cannot tell you how many times people have told me 'you should clamp that'. I usually just use tape on veneer repairs (small pieces) unless it may shift. Its always been fine. Thanks for the video!

[@tc8135]

Honestly that was also my biggest takeaway from the video. I feel so much better about my projects held together by painters tape.

[@DsHardWoodCreations]

Id like to see a follow up on this video on what is the minimal amount of glue needed to secure a joint vs drowning a joint.

[@ckmoore101]

I second this nomination. I've always wondered that myself. But like Suman says, Im putting possibly too much glue, and relying my choking of my clamp handles to squeeze out what it doesnt need. I'm a drowner, but have found the only downside of this is cleanup time, and using more glue. But I'm a weirdo, and enjoy the glue scraping/cleaning process....its cathartic.

[@rovcanada1]

As a non-woodworker who frequently puts bits of wood together, I'd also like to hear/see the results of flood v's sparing. As well as that, what about the effect of lightly moistening the joint face with water (to open the pores) before applying the glue?

[@jsmxwll]

my hypothesis on the 30m clamp 24hr dry boards is that the clamps force much of the glue out, but the bond after 30m isn't enough to the adherants to maintain the joint and so it weakens. i've had this type of result when overclamping joints, wiping up the squeeze out and then backing off some of the pressure. i had a tabletop split right down the glueline this way and ended up doing some testing to figure out why it might have happened. i found it was pretty well understood that too much pressure can starve a joint and i suspect that backing off the pressure after clamping is creating a similar situation.

[@rolandgdean]

As an owner of a WW business, (and an even smaller YT channel than yours...lol) this is very helpful information. I got into the habit of writing the time on my glue-ups and waiting about 3 to 4 hours with only enough clamping pressure to get squeeze-out along the entire edge. As to the LAST TEST...my theory would be that the initial pressure squeezed out most of the glue and then releasing that intense pressure left the joint a little "glue-starved" for final curing.

[@kellyschlumberger1030]

Hand-clamping kept enough glue in joint so it was not replaced by air (spring-back / rebound of wood sucks in air). You're right about "glue-starved".

[@HomeFromFarAway]

This males perfect sense. there may even have been air ingress once the pressure was removed from the glue starved joint. I'd love to see a magnified shot of the break

[@SheWhoWoodworks]

Love how thorough you were with this. You have saved me from the worry of "Have I clamped this long enough" I was at overkill with overnight glue-ups lol. Thanks Suman.

[@jgalt1981]

This is a super helpful video ! I didn't realize how much risk I was taking unclamping my glue ups at 30 minutes. You've probably saved many people at least one project disaster. Very through analysis !

[@AlexRicketson]

I have a video suggestion for your test rig. It would be cool to see testing done to compare fluted dowels, spiral dowels, regular dowels, and maybe miller dowels too for the fun of it. I'm curious if the friction of a regular dowel causes glue starvation, or if the different types of dowels cause any significant difference in strength in the joint. I've never seen anyone test this before and many woodworkers use dowels in their joinery.

[@devhermit]

By clamping you push excess glue from joint. When you remove clamps after 30 minutes you release pressure on wood so a little tiny gap can occur on joint, but there is no glue to fill that gap. So it doesn't matter that you leave it for 24 hours, joint is already weak. When you making joints using just hands or weak pressure, you don't push so much glue out from joint, you don't store tension in wood, so wood don't try to break that joint and glue can do the job. There is probably a little more glue in such joint but it doesn't matter.

[@archimedez]

Wow! No fluff, only the good stuff. Literally packed a 30 minute video into 10 minutes. Played at 1.5x that's less than 7 minutes! You won't find a video packed with more info per minute. Took me longer to write this comment than watch the vid - very well deserved. How could I not subscribe? Genius! Thank you man - been prayin for vids like this!

[@maetthu]

I like this video very much because as an engineer, this is exactly the type of experiments I'm interested in to understand why we do things the way we do them and challenge tribal knowledge or rules of thumb. I'm writing my very first (and hopefully longest) youtube comment here because I'd like to make a few suggestions that may make your future experiments/videos even more valuable. 1. Include information about the spread of your samples Instead of bar charts, I suggest using "box plots" as they are a common way to display information about the average and the spread of the samples together. With few samples like here, you may also just overlay the individual samples over your bar chart, but I'd still prefer some of the statistics that a box plot has to offer. Why this is important: you concluded that 4hr clamping is sufficient for you, because in average the joint is just strong enough, without considering how consistently this is the case. But would you still make the same conclusion if half of your samples are very weak and half of them are very strong, resulting in a just strong enough average? 2. Validate your assumptions The underlying assumption you make here is that with 24hr of clamping, the joint is as strong as it gets and it is still weaker than just wood due to being stiffer. It would be interesting to see experiments with more than 24hr clamping time to validate (or invalidate) that the strength does not increase further. Why this is important: assuming after 48hr of clamping you can double the strength compared to 24hr clamping, would you still just clamp for 24hr if you have a project where strength matters more than clamping time? 3. Separate potential causes to make fair comparisons Your experiment with hand clamping and letting the piece dry clearly shows that there are at least two major causes for joint strength. One of them being the clamping time and the other being the total drying time. I think these can and need to be separated in that you test the strength after the same amount of total drying time for all the samples. If you can keep all the variables except for one fixed, you can show which has how much impact. Why this is important: what if the clamping time has almost no impact (as long as there was some) but it's really only the total drying time that matters? I.e. would you still do 4hr clamping if after 1hr of clamping and 24hr total drying time you get the same strength as with 24hr clamping/drying time (Your hand-clamping experiment potentially indicates that this could actually be the case)? When repeating such an experiment I suggest to first find the clamping time that results in maximum strength and take that as a reference. Then, try different clamping times but keep the total drying time the same as the one that reaches maximum strength before testing the samples. And in the analysis, also show the spread of the different samples ;)

[@abydosianchulac2]

Excellent video! Two thoughts of mine you didn't ask for 😬 : - It would be helpful to see how all those clamping times fared with the recommended 24-hour unstressed period after removal from clamps (or perhaps a period that would add up with clamping time to 24 hours total to keep all the samples identical in total cure time). If the full day of curing took the 30 minute clamped batch halfway to the strength of the 24 hour clamped group, I'd be fascinated to see how, say, the 1 hour or 4 hour group would fare after the full 24 hours. Either case would still free up clamps much sooner then the common "clamp for a day" thing a lot of us do. -The hand-clamped results are fascinating! I'd love a comparison between those where you just pushed them together to a sample group you joined with rub joints. Would the atmosphere offer greater pressure in that regard? Would the joint be any noticably different from your first group? Again, amazing work, man! You more than earned this sub.

[@superwavess]

OH MAN. This is the deep dive I've been waiting for. Thank you for this!

[@superwavess]

A lot of woodworkers suggest clamping for 1 hour, but then not stressing it for 24 hours. Curious how those results might fair

[@superwavess]

But from this - I guess it'd be not much different from the hand clamp test! Interesting

[@kmcrafting4837]

You mean the directions on the bottle that he quoted and then summarily ignored?

[@charlesenfield2192]

My approach has long been, clamp overnight if there's no reason not to, clamp 4 hours when convenient, and clamp 2 hours when I need the space or clamps for something else. Regardless of the clamping time, I expose the joints to minimal stress for 24 hours. That doesn't mean I don't touch them though. Sometimes I'll start combining subassemblies into a larger project after 2 or 3 hours of curing time if doing so involves minimal stress on the glue joints. I've never run tests on the joint strength, but I've never had an unexpected joint failure either. 30 years of experience suggests 2 hours of clamping is adequate for normal joinery and normal use.

[@rpenm]

Love the evidence-based approach to woodworking, Suman. Could you put error bars on your averages in future? It's important to see how much variation is caused by the test variable relative to uncontrolled variables.

[@WoodcraftBySuman]

Yup- I’ll need to include error bars in the future bc folks are really interested in the spread.

[@brewtalityk]

and do you suppose that information would at all impact your decision when it comes to gluing? I doubt it.

[@tomgillihan]

Love the process you used, I'm 60+ years old and spent my life thus far as an engineer asking the questions you asked. Well done! About to retire and spending more time in the wood shop, been thinking about my glue ups, hum... and you just did 700% of the work. Thank you so much. Youre awesome, thank you. Honestly, I think you out engineered Tightbond on their instructions, and you were very graceful, well done.

[@olivier.gauthier]

Really love your channel. I personally believe that curing time matters more than clamping time. Another video perhaps? 🙃👍

[@ianellis9698]

To me the most interesting element of these tests is the no clamp test. I've seen some great videos discussing clamp pressure. Over time I've reduced my clamp pressure. I now clamp to achieve squeeze out and typically unclamp after 20 to 25 minutes and put the piece aside over night.

[@KlNGS0FA]

Great video quality

[@NauhFX]

Congratulations on your very carefully controlled methodology, I hate testing videos that don't even care to make sure the samples and force applied are as equal as possible, it made me really happy to see all the care you put into this, it doesn't go unnoticed.

[@garyconway439]

I saw somewhere on KZbin this tip: rub two small pieces of coarse grit sandpaper together, say 80 or 100 grit. Sprinkle just enough of this grit in a couple of areas where the clamping force is greatest. The idea is to compress the grit into the wood so that there is no gap created by the grit.

[@andyoliver539]

For the 30 min clamp, then 24 hour cure, perhaps the clamping force being removed after the glue began to setup (but not fully cured) broke some of the glue bonds as the wood 'rebounded' elastically after clamping. This would render at least part of the glued surface ineffectual at the bond interface. Based on the hand fit-up and 24 hour cure, it begs the question "are we typically clamping with too much force?" Excellent video, well done!

[@gerarddelmonte8776]

Valuable, thanks for posting. I usually clamp for an absolute minimum of 2 hours with Titebond III, preferably four. If I am building something where the joint will be stressed, I allow the 24 hours that Titebond recommends. For my boxes, where the corners are not stressed, I can continue after the minimum 2 hours clamp time. The most shop efficient thing would be to glue and clamp at work day's end, let it go overnight, then continue in the morning. Bullet proof.

[@Teckstudio]

As an engineer myself I have to say: Perfect execution! 🤩I love how you put attention to all the details! And the results are also very helpfull ... thanx for investing your time. 👍

[@bobbray9666]

I think you're missing the 30 clamping point. After 30 minutes, most joints are ready for the clamps to be removed. That can be good since the clamping pressure can distort the wood and removing before complete glue setup allows the wood pieces to relax and flatten out.

[@sgt_retiredcharlie4102]

Came over from Scott Walsh. Love your channel brother! You've definitely earned my sub. I know that these kinds of videos are very difficult to make and you need to take time to be with your family. No one on their deathbed is going to say, "I wish I had made one more YT video." Keep up the good work.

[@WoodcraftBySuman]

Thanks bud! Appreciate the kind words. And agreed- I definitely prioritize family time. Which is why my publish schedule is vary spaced out.

[@AbouzarKaboudian]

Thank you for sharing this video and taking the time to test. I know how hard this is. In my opinion, testing end-grain glued joints would be far more interesting as the joint would break mostly at the glue site and not the wood itself. That would truly show the glue up's strength. It was also previously shown that despite the old belief, end grain glue-up is far stronger than along the grain.

[@WoodcraftBySuman]

You make a really good point in better isolating glue set time and strength by gluing end grains instead. Unfortunately the reason i did not pursue it is because end grain to end grain glue up is not as common in a typical woodworking projects and I think people would find it a bit harder to follow the logic.

[@pacefactor]

What I find funny about this is that it tracks with my experience and practices. I always assumed cure time was the major factor, and clamping is mostly to ensure the most surface area for the glue is being contacted before it sets up enough to hold that pressure itself (how sprung joints work). I typically take my clamps off after 3-4 hrs as I only have a few, and unless the wood is particularly "featured" I really don't want to leave them overnight in those clamps.

[@bradnail99]

Titebond 3 cures more slowly than the other versions and Titebond 2 is the fastest cure. I glued thousands of glue line feet in red oak in the 90’s using TB2 because it allowed me to reuse my clamp rack sooner. I left it in the clamps for 30 minutes, then stacked the panels to cure 24 hours before thicknessing. Several factors contributed to the success of my efforts. First was the joints were right off the tablesaw, not planed. The surfaces were decent but not perfect. I believe that this helped prevent a starved joint. The hand-planed joints in the video did not require high clamping pressure, and too much pressure can starve the joint. Second factor is environmental. These were glued in Colorado where the air (and the hardwood) is dry, so moisture from the glue rapidly moves into the wood and the shop air, faster than in a more humid location. My gluelines never failed and I regularly broke cutoffs to verify that the joints were stronger than the oak I’m doing glue ups now in a 75% relative humidity shop with acclimated wood and Titebond 3. I leave the clamps on 12 hours minimum and wait another 12 before planing to prevent sink at the glue lines.

[@Jord032]

Your videos mix engineering and woodworking in a way I haven't seen done on youtube before, really enjoyed this. Keep it up!!!

[@edweber3041]

Hi Suman Very cool that Scott collaborated with you. You are our scientist! Thank you Ed😊

[@WoodcraftBySuman]

Haha thanks. We are friends in real life.

[@MattMcConaha]

The no-clamp test is good to see because I love clamping smaller panels with masking tape and I've always kinda felt like I was doing something naughty.

[@angeloperezceo8101]

wood glue in impressively strong. never expected a product to be this good.

[@shawno8253]

This was an interesting video! I liked how you did 5 samples per test.

[@colaoliver1587]

Nice Video. As a retired pro a note from experience. I would be sure my joint was good. No bow. Test by clamping one end lightly and examine the gappage at the other end. Apply glue and put boards together and wait so glue is absorbed on both boards. Then clamp. If you have use lots of pressure to bring the joint together, you are introducing stress into the panel. Fix your jointer. Glue introduces moisture into the wood. Remove as much squeezed out glue to allow the joint to dry out faster. I'd clamp for an hour or more. After removing the clamps I'd wait at least 24 hours before secondary machining. NOTE!!! You have added moisture to the wood so the wood at the joint will swell. WAIT!! as long as possible before sanding or planing the joint. Too soon and the joint will continue to shrink and you will have a slight valley at the joint.

[@t.davidthomas4430]

Great job covering the variables I've wondered about every time I am waiting on glue ups in clamps. Nicely done Sir.

[@jackdotzman2908]

Wow, heck of a video on wood glue. You answered a huge number of questions I’ve asked myself, clamp time, fit, etc.. Great video, thank you. Looking forward to your next vid, you a great job at explaining what you’re doing, why, and the editing is very good. Thank you, a woodworker from Missouri.

[@justsml]

One thing that most folks overlook: the roughness of the glued surface. If your surface is too smooth and clamped tightly it’s easy to force the glue out. I wonder what the impact would be when sanding/roughing some nooks and crannies, or scrape/cut shallow grooves? How rough of surface is enough? How much is too much? How does it affect cure time? There’s one lazy trick I’d love to see tested: prevent glue starvation: let glue air dry until tacky (5-15 minutes) then clamp and clean with rag and *warm* water.

[@Sembazuru]

I've seen a couple of your stress tests and I have one compliment on your test setup. A lot of videos that I see people doing similar tests they use a luggage scale and try to capture the readout with a camera to find the frame with the highest reading. Your setup is much better because of the peak-hold feature of your scale. LCD displays, especially on inexpensive luggage scales have a fairly slow refresh rate so the actual peak reading may never show on the LCD. The peak hold of your scale will actually capture the peak reading even if it happens between LCD refreshes. Thank you for the quality of your test setup.

[@byOldHand]

10 minutes were very enjoyable and time flew by. Thank you, it was a useful video. Be safe dear friend

[@jmi967]

Another set of tests I'd like to see are: (1) measuring expansion after releasing clamps at different times and letting glue cure after release to see if you can detect when the joint is cured enough to unclamp so you could potentially reuse the clamps on something else while finishing the curing ** (2) full clamping pressure tests (3) temperature change tests ** Given the difference between the two single tests (hand tight and 30 min clamp), I wonder if the expansion from declamping after the glue had hardened damaged the joint because it was too brittle but not cured. Hand clamping was while the glue was still workable.

[@paulruud5804]

Nice work! I have heard it said that a rub joint is plenty strong. It's not quite your clamp-free treatment, but that lore (and my experience) are consistent with your results.

[@deanaoxo]

Love this, I think not touching the joint after clamping is the most important. Often I take the clamps off after 2 hours if I have a lot of glue ups, and not enough clamps(as no one, no one ever, has enough clamps). Great video, love science.

[@RYwoodview]

Yes! You make valuable, quality video, Suman. Doesn't matter if they don't come out often. Good stuff is worth waiting for, and it can only come as you are able, not as others wish. Very helpful to quantify the time effects of clamping glue-ups. Adequate clamping pressure, released at 4 hours but NOT disturbed for 24, and on to the next tasks. It would make sense to have left them all for 24 hours as directed, to see if it matters when the clamps were removed. I suspect it wouldn't matter so long as the glue lines were intact. You are so right that the quality of the edge match is most important. And that means you don't need a clamp every 3 inches either. I glued a 3 piece panel of cheap wood with jointed edges for a painted sign that rotted away after 15 years in the rain, snow & ice. But it never came apart. Thank you so much!

[@RILRIL1]

I wonder if greater clamping pressure causes more glue to squeeze out, but then if that clamping pressure is released before the glue dries/cures enough to hold the joint tightly together, then there joint has an effective glue deficit. Less pressure means more space between fibers, which means more glue is needed.

[@BigAlz11]

I agree, soon as I saw he had transducers on the clamps to measure clamping pressure I was eager to see variant in clamping pressures tested.

[@randywelch55]

This is an excellent video on glue ups. I usually wait at least 1 hour before handling or working with glued material on fast moving projects, but now will wait longer after seeing you video. Thanks a million

[@cgrovespsyd]

Very very informative! You answered nagging questions that I’ve had for decades! No more overnight clamping for me!

[@Cainitech]

This was enlightening. Congratulations on your method, the editing, the data collection and everything. Awesome work

[@Matt_of_the_mountains]

I watched this after seeing the joint testing video you did with Scott Walsh, and you've definitely earned my subscription! I only own a few clamps and I'm definitely one of those who leaves them on overnight if not a full 24 hours so knowing this will help ease my anxiety about taking them off sooner. Thanks, and I look forward to seeing more of your testing videos!

[@memory_null]

My assumption about the hand clamp vs the 30m clamp is that mechanical clamping forced most of the glue out and before it had enough time to set the wood sprung apart enough to leave microscopic gaps. I have no way to prove this though.

[@WoodcraftBySuman]

I agree. Feels like the most plausible reasoning. at the end of the day, any of us could disturb the 30min clamp project enough to weaken it. Best to clamp it longer till the glue strength really kicks in.

[@feralart]

It's the difference between dry time and cure time. There's chemical reactions taking place that give it that strength. It all really comes down to the level of stress a project will need to survive.

[@BobStCyr]

Great testing. Another factor I have found (50 years since I was an apprentice) that you mention is glue line thickness. We used to do panels with no clamps - rubbed joint. It would interesting to compare - several panels clamped together and several with a rubbed joint. For those unfamiliar, take the 2 pieces with good glue joints, glue the edges and press the joints together to ensure glue spread and also squeeze out any excess glue (with experience you should be able to apply just the right amount of glue for a .003 to .006 thick glue line) then stand the “panel “ on edge allow to dry. For wide panels lean 2 sticks against the wall to support the panel at a nearly vertical angle.

[@Eddie.Mootsen]

thanks. really well done. releasing clamps after 30mins releases pressure and weakens the glue. Personally I: put a few clamps on & leave them on overnight.

[@metetong2065]

I just LOVE theses kind of test base video where we get to conffont our habits to rigorous testing method and growing from that new knowledge

[@poodlelord]

This is why I use glue and brads to assemble stuff and just move right along. No need to use clamps at all for most joints as long as the boards are tried and true!

[@ajmuffinstuff1]

I'm going to blame that clamp removal discrepancy on preload. It's a fantastic topic and actually the way that screwing things together works. Theory: because the glue was under pressure, and then not it's change in compression messed with the firming up of the glue. The reason the clamped for 24 hours was slightly stronger was because it's under pressure (preload)

[@SeraphsWitness]

You need more subscribers, my guy! I can't believe I hadn't seen your channel until now.

[@globyois]

I love Titebond III. However, I have believed - from my woodworking experience [I used to be a luthier] and am now a woodcraftsman - that it is weak unless it is left undisturbed for 24hrs. After then, it is an excellent bonding agent, and as you have shown, only 4hrs is necessary for reliable strength. But good to have your scientific experiments to draw from, really appreciate it. Great work, thanks.

[@prsearls]

Most of my glue-ups are segmented rings for wood turning. This is useful information to me, especially allowing the joints to cure for 24 hours. This will speed up my assembly process while still producing a strong, safe bond.

[@Marty59143]

Saved me a pile of testing , thank you. I am also sharing because I think someone who takes the time to do testing is a valuable asset to any wood workers out there.

[@WoodcraftBySuman]

Appreciate you! 🙌

[@samscheef2494]

Love your scientific approach to woodworking issues. Very professional and informative. Keep up the good work.

[@FisherCatProductions]

This is among the most valid tests of ANYTHING I've seen on YT. The most surprising result was that the "hand" clamps were actually stronger at 24 hours than the 30 minute clamps were at 24 hours. I suspect it's because heavy clamping squeezed most of the glue from the joint, while the hand clamp joints retained significantly more. Without the added benefit of heavy clamping overnight, the 30 minute test squeezed out most of the glue, relaxed the interface at a point when it was still pretty weak, and had substantially less glue throughout the 24 hour period. As others have said, a much more useful result would now be to test clamping at 1, 2, and 4 hours to see how they compare after 24 hours drying time. That represents what we all would consider doing, as no one wants to tie up their clamps for a day, but we would go longer than 30 minutes if we got reasonably stronger joints. EXCELLENT video! (BTW, that is the only glue I use, and I know from experience that 30 minutes is not long enough for structural projects. I always go at least 2 hours, or more if I don't need my clamps back.) [50+ years playing with wood]

[@alvagoldbook2]

Great video, and I always appreciate anyone who tests conventional wisdom to see if it really holds up. Some years ago I was doing a project of making wood covers for baseboard heaters. It was all made out of poplar but required a ton of glue ups. But all of them are under low stress. I found that just holding the pieces together with my hands for 5 minutes was sometimes sufficient. 4 years later none of these glue joints have failed. Typically, I prefer to leave major glue ups in a clamp for 8-24 hours. But for minor things, where the wood will be under low tension and not see serious abuse, then shorter clamp times work just fine.

[@SpencleyDesignCo]

great video suman!

[@WoodcraftBySuman]

🙌

[@Tobsen660]

My explanation for the 30min test would be, you press the glue so thin that when you release the clamps it springs back a tinny amount and the glue loses contact in some areas. When you use your hands only there is no springback and the glue can bridge over these areas . Very interesting stuff and usefull for everyday glueups. My takeaway... If using clamps, leave them at least for a few hours. I often release clamps after 30minutes, I never had a problem so far but your test lets me rethink.

[@Tobsen660]

Would have been interesting how the 10min clamptime would have compared after 24h. Might have been stronger then the 30min if you maneged to get it out of the clamps with out moving it.... Mortise and tenon for example, where you use clamps to pull it tight and then, after the open time, release the clamps. All and all, if you work clean I don't think there is a real diferents at all.

[@ilaion11]

For the 30 min clamping, 24 hour drying, because the glue is not yet dry, and the clamps did pushed most of it outside the joint, when you unclamp them, a small gap would form from the released 200psi of pressure, and that becomes a weak point, not to mention there is no much glue left. Because you didn't applied so much force on the hand pressured ones, enough glue stood between them and no air got in. On the other hand, what I would do before putting pressure, would be to let the glue get sucked in for 5 minutes, so the glue penetration would offer more support for the final body of glue inside the wood, even if that is only 1mm. I would just test this to know for sure, but I lack the means... Nice video BTW, first time here!

[@kthoennes]

Great video, thanks so much for taking the time -- very useful and interesting, but with a "real life" competing for your time, impressive you were able to do such thorough and careful testing, and then the video editing.

[@kevingeaney7741]

Thanks for a very good video. I glue up segmented bowls and vases etc with a glue joint approx 20mm wide, then I turn them on the lathe down to a wall thickness of 6mm 1/4inch and I don't have failures . But I glue things in an un conventional way.. I apply the glue to the surfaces and let it sit for a minute to soak in, if there are any dry spots I apply more or just spread it with my finger. Then I clamp up tightly. I don't have to worry about starving the joint of glue because the wood had time to absorbe it before clamping. I clamp for an hour, and I'm very careful to avoid temperatures below 12°C I bring the glue into the house overnight. By the way, this joint will GRAB very quickly, so you must have the parts lined up and the cauls and clamps ready in advance. If you disturb it after it grabs the joint will fail.

[@unperrier5998]

When you remove clamping after 30 minutes, you're breaking the bonds that the glue has started to form. In particular the glue is able to pull itself out of the wood fibers. That's why it's weaker than no clamping at all, because no clamping has not been disturbed and was able to form good bonds, although these bond did not get as deep into the wood fibers because there wasn't enough pressure (which is basically how much force is applied per unit of surface)

[@PureNrGG]

Edit* I probably shoulda finished the video before commenting haha. In any case, I'd be interested to see the differences anyways! Amazing video! What I'd be interested to see is this same test, except instead of trying to break the joint immediately after the clamps are removed, let the glue fully cure To avoid confusion here's an example. Clamp the wood for 5 minutes, remove clamps, and let glue cure for 24 hours. Come back and test the joint.

[@WoodcraftBySuman]

Agreed. It would add more value for sure. Just didn’t have the time or capacity to double up production schedule for this video.

[@PureNrGG]

​@WoodcraftBySuman I edit my comment if you didn't see. I should be more patient and watch the full video before commenting haha. In any case, I completely understand. I have some limited content creating history and I know first hand the limiting factors of being small and just not having enough time to do everything you'd like to do! Still, amazing video. Youve just gained another sub for what it's worth 😊

[@WoodcraftBySuman]

@@PureNrGG haha thanks!

[@professorbellorum]

I think it's a fluid volume versus pressure thing. When you apply the clamps, you squeeze a lot of glue out of the wood in the joint area. If the clamps stay till the glue cures, then that small amount of glue is still plenty to do the job, but if you remove the clamps after only 30 minutes when the glue is still uncured, the wood decompresses, and suddenly has the capacity to absorb more glue. But you squeezed all of the glue out of the joint, so there's now actually less glue in the joint bonding to wood. Contrast this with your hand placed wood, you never squeezed the glue out of the wood, so there was plenty of glue present to fill the joint area. Good bond.

[@feasterfamine836]

Excellent tests! For decades I have suspected that clamping is mostly insurance of the tightest possible joint for a given glue up and this seems to confirm :)

[@AntonioKuilan]

This is how a science of woodworking video is done. Thank you for being a hero.

[@ajosepi1976]

Just found your channel. Last thing I clamped up was clamped for a week because I forgot about it. 😂😂

[@WoodcraftBySuman]

Yo let me test that real quick 😂

[@mrpete5482]

So, you've made the world a better place. Thank you, Suman. + Loved your product link 😄😄😄

[@WoodcraftBySuman]

Haha thank you! It always amazes me how much some folks try to push to make a sale.

[@pro-woodworking-tips]

Thanks! I have had bosses insist on running things through the planer after 15 minutes, but I always had other thing to do in the meantime to let them sit for a while longer. About an hour into the glue up, when the glue is somewhat still soft What I have been doing is removing clamps one at a time to remove the glue and then replacing them from the panel. So instead of releasing any pressure is to keep the clamp about ½ an inch above the wood to be able to scrape the glue off. One thing I have been doing for years now is to let the panels sit for a week to allow any water from the glue to evaporate off the wood. When first glued the panels have a swelling like a mountain ridge and if you were to plane or sand it flat, it then dries leaving a valley.

[@darthstewie76]

This is honestly one of the best videos I’ve seen. Very informative. Keep up the good work!

[@psdaengr911]

My guess is that machine-clamping for a few minutes forces more glue out from between the boards than hand pressure and relieving the pressure allows more evaporation around the perimeter of the joint. The first leaves less glue to penetrate the wood during setting through the opened cellulose fibers into the walls of the adjacent intact fibers and increase tensile strength. The second allows the glue in the joint to cure at different rates, possibly making the glue at the periphery more brittle. You don't have the tooling to do it, but an offset shear test would be a better test of the strength of the joints than bending.

[@paulgendron8416]

I'm impressed. These were very good tests. I worked in a physical test lab for a wire and cable manufacturer for about 10 years and found your test setups to be very consistent. I did find that due to you using a chain fall the rate of separation varied from test to test. The better way (and I realize you had no access to this) would have been an electric chain fall to maintain a more consistent rate of separation. Also the wood should have been milled using a planer and jointer to ensure more exact dimensions and a 90° corner. I'm sure there would be a few other preparation variations, but overall you did excellent preparation. Good work. Oh I almost forgot, it's important to have all the equipment used to be calibrated. Again you most likely have no access to this as well. But you used what you had.

[@0num4]

Bravo, sir! This is an excellent approach to the scientific method--you control for the things you can, account for extremes in deviation, and publish your results in an easy to understand way while acknowledging constraints. I'll definitely be reducing the clamping time between phases now that I understand this. I mostly make picture frames and smaller jointed items anyway. If something is clamped for 24+ hours, it's not a big deal, but I won't worry about the joints being too weak after 2-4 hours, so long as no additional stress is added in that time.

[@michab4083]

I love your testing setup & method, but the more interesting question (for me) would have been that of strength after a total curing time of (say) 24 hours for various clamping times, i.e. the comparison of different clamping times, but identical total curing times. Typically, you want to reduce clamping time because you want to proceed with your project, but nobody would expect or require final glue strength after a curing time of 1 h or even less.

[@TwZlr.]

I love your perfect explanation of a well executed scientific process. From observating your experiment, I am smarter now than I was before.

[@Qu4NtuM]

I've been making panels out of pallet wood. Planed faces, some bowing, heated but not too warm shop, Titebond 3. I have have a limited amount of clamps etc, so I can only do 1-2 panels at a time. I leave them in clamps for about 90min. After that they are pretty solid, but I can still easily scrape the squeezeout off. Next day they are good and ready to go in the planer. I have done about 30 boards like this and so far no problems.

[@juhs]

Amazing video! I'm a clampaholic and not ashamed, if there's room to get another clamp on it I'll squeeze it in.. If I'm out of clamps I'm happy to have an excuse to run to harbor freight 😂

[@ndeleonn]

I am a retired scientist who now does woodworking. This was an excellent attempt at quantifying the strength of different types of wood glueing. However, the final conclusions are a bit premature because it is not comprehensive: you need to take into account and consider all of the variables. These variables include types of glue, types of wood, wood grain, wood density, wood thickness, span of wood being broken etc. . Nevertheless, this is just about the best study of wood glueing I have seen on KZbin. Well done.

[@WoodcraftBySuman]

Thanks Nelson! Yes it’s important to keep in mind that my goal here is not an academic exercise for publish-worthy data. It’s really to demonstrate some of the principles in a quantifiable way for a general woodworking/diy audience to take away a few high level knowledge. To your point, more variables could be added but adding another type of glue (as an example)would compound the testing 2x; something I do not have the capacity at current level of family and professional responsibility. I did control for wood species, thickness, and span of wood being broken. It’s hard to control for grain which I alluded to in the video. I did use boards from the same stack (and presumably same tree). Appreciate you watching!

[@ndeleonn]

@@WoodcraftBySuman yup … understood. Your study was excellent for the intended audience.

[@BMSculptures]

Amazingly detailed video. This is going to save me so much time (and clamps) for future projects. Thank you Suman!

[@WoodcraftBySuman]

Thanks Blake! I can’t wait to see the bull weave sculpture!

[@TommyT888]

Great video. Very informative. The non-clap results were very surprising to me. I'm going to think twice when I do my next picture frame...I usually struggle with a complex set of clamps trying to distribute equal pressure on all sides