How to fix a badly twisted slab/board without losing much thickness

[@buffalojones341]

Subscriber 403 here. What a great tip. I feel like I’ve watched all the KZbin videos on woodworking, but I sure haven’t seen this idea before. Great tip.

[@ardemus]

The worked side of that wood is beautiful and fascinating to look at! There would be a market for that, filled with epoxy or inlays.

[@MyLifecraft]

Nice. I usually just force the warp out with straight pieces glued either around the perimeter, or on the bottom of the table. I have a kitchen table that was cupped, so I glued some 4X4’s on the ends and a year and a half later, it’s still flatter than ever

[@ajipaul8303]

I have a 60inchx30inch cupped slab with approximate 1 inch + thickness . any idea how can I glue 4x4 to straighten it?

[@MyLifecraft]

@@ajipaul8303 For slabs i would try to flatten it out with a plainer or surfacing jig 1st. a surfacing jig should get most of the bend or cup out. Then get some pieces of 2x4 or 4x4, place on bottom in a position where the grain on your 2x4's intersect, or cross with the grain on the bottom of your table, then use clamps to pull the remaining bend out, and glue them together.

[@RILRIL1]

Brilliant! I will absolutely be doing this to save some twisted but stunning 5/4" figured birch slabs.

[@James-go8ct]

Extremely helpful. I have an English walnut slab I am using for a clear epoxy build. It twisted slightly during drying. Can’t use c Chanel’s because it’ll be clear. Probably one or two other videos about this but non as in-depth. Thank you.

[@JonDurbin]

Appreciate the feedback, glad it was informative! Let me know how it goes.

[@kirn.creations]

The video I was looking for. Thank You Sir! Explained well and showing your technique helps put it in perspective. Subscribed🤙

[@ARMYStrongHOOAH17]

I'll be honest, I was skeptical in the beginning trying to wrap my head around your drawings. Awesome technique, beautiful product.

[@JonDurbin]

Totally understandable, I am no artist haha. Maybe next time I'll make a prop/demo piece from 2x4 so it's easier to explain/visualize.

[@ARMYStrongHOOAH17]

@@JonDurbin I think you explained it well I just couldn't figure out wedging it. I was imagining a wedge going al the way through the material.

[@braytonbailey3782]

Great video! I have 3 white oak live edge slabs and I was looking for a way to flatten them without taking too much off. This is perfect. They are cupped so I believe I can just work longways like you did. I was wondering are those small spacers wedges or just straight pieces of identical thickness.?

[@jnjdiversesolutionsllc3356]

Was thinking about doing this same technique to a walnut table I am currently building for a customer. I had never heard of it being done before, but making round faces with plywood gave me the idea for the slots. You’re awesome Jon, thanks for having a killer idea and posting it on KZbin. These are the things I wish people shown more often. Too many board planning videos and not enough skilled videos. Sub 500 here btw!

[@JonDurbin]

I appreciate the feedback and the sub, thanks!

[@deeseneviratne]

Such a helpful video, thank you Jon! I’m in the process of making and documenting my first slab table made from White Oak and after glue up and c channel, it cupped due to extreme heat while I was in laying bow ties (my workshop is outside and I live in Australia 🤷). Most of the cup straightened after the slab re-acclimatized but still a slight cup which I’ll use these stress relief cuts to help solve. Any merit in filling the relief cuts with epoxy after the slab straightens?

[@JonDurbin]

Glad you found it useful. I've seen others epoxy fill, but I haven't tried it so I can say for sure. Two potential downsides to epoxy: It usually shrinks when curing (not a huge amount, but it could be enough to pull the warp back in), and it adds quite a bit of extra weight.

[@Derwentmole]

Interesting. I thought of trying epoxy too but not going ahead with it at the minute. Be interesting to know how it turns out if you manage it! Let us know man. Cheers 😉👍🇬🇧

[@CoupleofBunkies]

never seen it done like that thanks and you gained a subscriber

[@brainwashingdetergent4322]

Nice technique! And again, killing it with the music selection!

[@JonDurbin]

Thanks!

[@Derwentmole]

Nice work, thanks for info and sharing. I’m about to flatten some large oak boards with the router. I cut them 2017 with the chainsaw Mill and they’ve dried well being weighted down, without much movement at all. I’m interested and anxious to see if the first one as a coffee table holds shape after getting into the house. I’m considering rebating angle section into the base as you have with the C-section….purely as I don’t have C section which I would have preferred. Fingers crossed. Cheers again. 🇬🇧🇬🇧🇬🇧

[@KieuPho]

Great solution! Pls continue this type of work. Thank You Sir.

[@rattlejake0422]

Certainly can't argue with the result! I confess to being curious about the longevity of this technique and if your wedging battens - which kind of seems similar to what you're doing here? - holds up over a long period of time (i.e., decades). Nice work, overall!

[@JonDurbin]

Time will tell! I will of course fix the table if something should happen while I am still capable of doing so.

[@FharishAhmedPortfolio]

Alright... This actually helped me out, way more than you know. I think this deserves a sub!

[@JonDurbin]

Glad you found it useful!

[@FharishAhmedPortfolio]

@@JonDurbin No worries, keep up the good work!

[@williambranham6249]

This is a follow up from an earlier comment. I watched another video by a professional who made a similar table. He used a similar technique with c channel although he did not use the type with slots nor did he rout the inset for the c channel a little longer and wider. After delivering the table it split as well as deforming the inserts and bolts. The humidity in the customers house was so low he used a humidifier. Over time the table was ruined. He feels his biggest error was in not using slotted holes in the c channel. Secondly, I find that weighing my project wood after cutting pieces but before dimensioning and checking weekly gives me good info on whether the wood has acclimated. Good luck.

[@JonDurbin]

I always cut slots in the c-channel; basically drill two holes and remove the center with a grinder, and I always make the inset wider and longer than the steel, for that reason. For this project, I dried it down to 7-8% (verified with Wagner Orion 950 moisture meter), then let it acclimate in my shop for about a month (kept at 45% humidity), then once complete I kept the table in my house for about 3 months waiting for the client to be ready for it, during which time the table did not warp or split at all.

[@bitsurfer0101]

I would like to see a C-Channel process video since I've never done it myself.

[@MrSeminole77]

nice content and replies for additional clarity- thanks and keep up the good work!

[@tfaf5149]

Is the table still flat?

[@jonwatkins675]

Appreciate the information. I’ll be in touch with questions.

[@Leightr]

Not at all "fine" woodworking, but I'll often buy from the "cull" pile at my local place (the warped lumber everyone else passed on) for building sheds, fences, etc to save money and I'll then just leave it in my shop with some heavy weights flattening it out and that's worked pretty well. I wonder if it's due to the stuff not being completely dry when I start.

[@Alicia-ig7cv]

I just removed peeling veneer on an antique buffett top. I did the wet towel and hot iron method. I took the whole buffet out in the 20 degree weather then back inside at 68 and its teisting on one corner that was loose on top. Hoping i can fix it right

[@JonDurbin]

I'm sure you'll get it fixed up!

[@colinellicott9737]

Cool solution - thx. Not sure I'll ever use it but good to know.

[@DaMaartenvdBerg]

Nicely done. As an amateur/woodworking noob I ruined a piece of wood by airdrying it near a heater, but I think I can fix it using this method. Question; Can I apply this technique without the steel frame? It's only a 16x52 inch board, plus inexpensive wood so is it even worth it?

[@JonDurbin]

It’s certainly possible to do without steel, but it would depend on the amount of warping, how stiff the wood is, etc. Personally, I would definitely try it on a cheap piece of wood! Making a mistake on expensive materials is pretty gut-wrenching, might as well practice with something cheap.

[@toxicburn1]

Damn those cuts look sexy! My ocd loves it :) Thank you!!!! for giving me an idea with my project!!!

[@davidhill7397]

Thanks for the video it helps out a lot . You saved my table.👍👍🥰

[@trep53]

Wow that was a interesting approach to flattening your slabs. How did you develop this idea/method? I’ve looked at slabs when shopping rough sawn lumber and the sky’s the limit on price so any effort to make a less perfect slab usable is worthwhile.

[@JonDurbin]

Mostly inspired by other woodworkers using a similar method, partly just from knowledge of how to do bent wood slabs and things like that.

[@bitsurfer0101]

It would be better if you could get the vocals louder and the music softer or cut completely.

[@riccardos.3427]

Great tips, I hope I can fix my twisted board; I have a question: do you wait for the slab to be flat after the relief cuts to install the wedges, right?

[@JonDurbin]

This is one thing I failed miserably at explaining in the video unfortunately. After I cut all of the reliefs, I clamped the slabs down everywhere so it would be flat before inserting the wedges. Relief cuts won't flatten the board immediately, so you need to flatten it under pressure, then the wedges actually apply the force that flattens the board.

[@riccardos.3427]

@@JonDurbin Thank you for the quick response!

[@DreamRiverDesigns-hx1ko]

@@JonDurbin Thanks for the video. So for clarity, the wedges are not wedge shaped, they're just straight pieces fitted tightly into the grooves? Then when you release the clamps, they prevent from the twist from returning?

[@Masterg400]

you sirt are a genious thank you for the indepth guide and explanation this is trully amazing

[@matthewjason5330]

I’ve been thinking about doing this but. I’m curious how this table has done so far if it split or cracked on top? Thanks

[@JonDurbin]

Not at all, still flat and doing great!

[@markhedquist9597]

Huh. Very interesting. Do the unfilled channels get filled with anything later? Epoxy or something? Also, I spotted a six inch jointer in the background. Is that an old craftsman? If so, I have the same one. $100 find. Also, I read some other comments and you mentioned moister content in your reply. I'm in the market for a moisture meter and wonder if you might recommend one.

[@JonDurbin]

I left the channels empty, but did make sure to seal them all really well with lacquer to reduce uneven seasonal moisture loss/gain. Yes, 1950's craftsman, still going strong! I have used 3 moisture meters: can't recommend the pin kind because they can only detect surface moisture and have caused problems for me. I've also used the General Tools MMD950 pinless meter, which is decent but only gives relative measurements. The one I use now is absurdly expensive but works beautifully, the Wagner Orion 950 pinless.

[@Flipping_Assets]

You work inside your house?

[@gordroberts53]

Brilliant!

[@williambranham6249]

VERY NICE RESULT! Did you have a concern while working or do you have a concern down the road that a crack might develop? Also were these air dried or kiln>

[@JonDurbin]

Thanks! The boards already had a few big cracks, so it was a big concern. I cut all of the stress reliefs first before applying any pressure, hoping any of the stress from pressing the board flat would apply across those cuts instead of the existing cracks or random spots, and I guess I got lucky! The boards were air dried for 2 years, just outside under a tarp, but they were still about 20% MC when I got them. I built a little dehumidifier kiln and dried them in there for about 3 months down to 7-8%. I added several splines and bowties across the various cracks, along with epoxy for the larger spots. Between all the reinforcements and the steel C-channel, I am pretty confident in the stability, but if something happens I will fix it!

[@TheBearGrylz]

I like your method, I’ve used it before. But after all those cuts and wedges, wouldn’t it be less work to just router sled the whole thing to straight? I guess you didn’t want to lose thickness.

[@JonDurbin]

Yeah, the opposing corners were both warped 2"+ from the surface, and it was only 2" thick, so just jointing it I'd have nothing left.

[@Brettly01]

so i take it you flatten out by clamping it flat and then use the wedges to stop it springing back when clamps are removed?

[@JonDurbin]

Yep, stress relief cuts while unclamped, then clamp and insert wedges.

[@russellrobbins791]

Do you think filling the relief cuts with epoxy after making the relief cuts and flattening the slab would work? Just curious but your results are great!

[@JonDurbin]

Possibly, but you'd have to make sure it was truly, fully cured (30+ days). The wedges actively push the cuts apart, whereas epoxy would just prevent collapse.

[@bradley3549]

That was my first thought when thinking about this. If I had the opportunity to try this I'd consider making the relief cuts, clamping the slab down either dead flat or with a little counter warp, fill with epoxy and let it cure. I wouldn't use a router though since I think all that pass really necessitates a thick pour slow cure epoxy. With a thin kerf circular saw a standard epoxy could be used I think and it would cure much faster.

[@user-dt9fo9cy8b]

That is great! Genius!

[@ewaldgerber956]

What glue do you use adding the spacers?

[@JonDurbin]

Tightbond 2 dark

[@szeredaiakos]

If you had any idea what a couple of steel bars do to a tabletop over the course of 5 years in a temperate climate you'd avoid it like fire.

[@H2Dwoat]

Hi, do you think soaking the slabs for several days before inserting the wedges would help reduce stresses in the slab as it drys? I have no idea by the way just asking.

[@JonDurbin]

Good question, it may help get the initial shape but then long-term would likely cause more problems, because you would be drastically changing the moisture content. Wood should be equilibrium moisture content for the region it's going to live in when working on it, so in this case the boards were already down to 7-8% before, then stayed in that range during and after. Boards tend to warp quite badly when they dry too quickly or unevenly.

[@mikean1123]

DUDE!

[@BeaulieuTodd]

I’m highly suspicious of gluing in perpendicular stock like that. It goes against everything that’s universally practiced with solid wood. Seasonal grain movement.

[@JonDurbin]

OK.

[@cancelchannel3394]

Just soak in water and lay out on a flat surface with weight on top

[@JonDurbin]

Even if that worked, which seems unlikely for slabs of this size, they would just warp again once dry...

[@cancelchannel3394]

@Jon Durbin not if slowly dried properly, seen it done, you just have to know the natural characteristics of wood "/

[@cancelchannel3394]

All that's necessary is to rehydrate the wood, this guy is ruining the wood due to ignorance "/

[@JonDurbin]

Agree to disagree my friend. The table is still holding up great (and flat).

[@50calpulse76]

The best fix for this is buy better lumber