Will 3D printed gaskets melt? TPU tests

In this video I do an experiment following up on my first video about making TPU gaskets. I answer some questions and explore more about this material to see in what applications in can be used. I soaked it in fuel for 2 days to see if it would expand and do some rudimentary temperature tests on it to see what kind temperatures it can withstand.
If you have not seen the first video here is a link
Can you make 3D printed gaskets - • 3D printed gaskets? An...
and the follow up to this video
Heat treating TPU gaskets - • Annealing TPU to incre...
and another follow up
3 ways to design a gasket in for 3D printing - • 3 ways to design a gas...
Tools used in this video:
Sovol SV01 -amzn.to/3LwYxN0
Creality Ender 3 Pro - amzn.to/3iNQPld
TPU Filament I used - amzn.to/3RV0vLC
UNI Multimeter with temperature sensing
amzn.to/3O9tU2e
High temp probe
amzn.to/3v5zeuH
Mapp gas torch head
amzn.to/3EatvIl
The previous links are affiliate links, the channel gets a small referral fee if you use them and buy anything, it costs you nothing.
Video chapters
00:00 - Intro and explanation
00:21 - First experiment (does TPU absorb gasoline and swell?)
04:32 - 2nd experiment - Temperature resistance TPU (glass transition)
10:05 - Summary of findings from this video

[@ihatejoze]

I made a 90° elbow out of TPU from my valve cover to the intake system for the PCV on my car. Under hood temps are fairly high (not sure on the exact number) and it’s regularly exposed to oil and has held up well for nearly a year now. The orange color it was has darkened due to the oil exposure but it’s still doing it’s job

[@davib8963]

If heat is a concern, it is very effective to print molds in PLA for casting two part tin cure silicone into. A simple two part mold can be created to make gaskets like this. Could even use TPU to make the mold if you want to be able to bend it when demolding, which might be helpful for weird shapes.

[@theeddies]

Good idea, thanks!

[@james10739]

That's not a terrible idea but generally you are replacing paper gaskets so with all that effort you probably would just cut one out of paper or cork but also I'm not sure how thin you could easily get but I'm sure there are some good uses for that method

[@jaykoerner]

@@james10739 if you're going to this effort I think the proper solution is a vinal cutter tbh, and just cut out paper or rubber gaskets with the plotter, if your sole use is making gaskets the plus side is it's cheaper and faster to buy into, downside is probably blade life but blades are cheap

[@jonjohnson102]

@@jaykoerner most maker spaces will let you use their cruict machines for free or for a monthly fee, which gets you access to a shit ton more. (If they have a criciut)

[@pebrede]

Your experiment is valid, with the suggestion that approximately 100c is the re-usable/non deteriorating operating limit. I would suggest for long term testing that the clamped thickness and rebound would add to the vital statistics when subjected to a max temp of 100c. The tractor experiment will certainly provide valid data. A valuable data set and of extreme interest to many. Good luck and take care.

[@theeddies]

That is exactly why I like doing these in stages because at every stage I get good suggestions of concerns I have yet to consider. I can clamp the gasket between 2 pieces of aluminum at a known torque, and heat the aluminum up to a known temp. and see if there are any changes. I need to control the heat better for that. Maybe an old toaster oven that I use to dry paint on small pieces would work. Thanks, Eddie

[@karlosss1868]

Very helpful... thanks. I ended up making a gasket for a lawnmower carburettor & works perfectly.

[@danielsweeney8164]

Your tests and detail very helpful and to a level of satisfaction so that I don't have to do the same tests. Great stuff, liked and subscribed!

[@theeddies]

Thanks Daniel. I have not completed the 6 month follow up video but all the tests on my machine were successful.

[@tylersoares8120]

So detailed! Thank you for being the researcher you are. I just stumbled onto your video thank you sir, I have subscribed.

[@theeddies]

Thanks, all the best!

[@sebuls]

"Something happened to my first temperature probe, i think it was when i set it on fire" Classic.

[@chuysaucedo7119]

Good stuff ! Thanks

[@AaronAlso]

Don't know if you have one, but 15psi in a pressure cooker is about 250F. (depending on altitude) It would be nice if TPU could be used as a seal for canning. Would have to survive 60-90min at this temp&psi. If it can survive several cycles like this, it will be sufficient gasket material for 95% of applications.

[@TheKnacklersWorkshop]

Hello Eddie, Interesting tests and I would suggest very valid... Maybe the only one I would add would would be soaked in petrol and two-stroke oil whilst under compression as that is what they would be in whilst being used... Take care. Paul,,

[@theeddies]

Thanks Paul. I will keep that in mind, I have a couple other tests coming as I have time. And one of those involves putting the gaskets under measured compression. Best! Eddie

[@Just1GuyMetalworks]

That's some "good to know" info right there 😊.

[@theeddies]

I do strive for the "good to know" info as opposed to the "who the hell cares" kind😄

[@Just1GuyMetalworks]

@@theeddies lol, amen to that! 🤣

[@bulletproofpepper2]

Kool thanks for sharing!

[@theeddies]

Thanks for watching Sam.

[@siccamade5150]

I've tested tpu with brake fluid and it's held up for a month now!

[@theeddies]

Nice, good to know. Thanks!

[@stiffybrian]

Thank you so much for this test. I'm printing airbox to carb pipes for a motorcycle. I don't think they will get hot but will strap a temp probe to them on a run. The negative pressure in the pipe will want to collapse them which wouldn't be appreciated.

[@theeddies]

If you have a good amount of wall thickness, collapsing should not be a problem. TPU should be stiffer than rubber for the same thickness.

[@SebbyRuiz]

Did you ever end up doing this? Buddy wanted me to prototype some velocity stacks for him out of TPU and would love to know if they’ll melt before I go ahead and do it

[@angemichelbach5064]

Thanks!

[@theeddies]

You are most welcome, thanks for the tip!

[@kimber1958]

thanks

[@theeddies]

Thanks, Kimber

[@machinenutdel6764]

Morning Ed. the real world test will give you some interesting answers

[@theeddies]

Yeah, the real world always finds a way to the best laid plans.

[@vygag]

i think it would be more important to know at what temperature TPU gasket starts to leak while it is sealing some parts. Like, would it hold up as sealing gasket for coolant pump on a engine? Being clamped between water pump and a hot engine for some time, would eventually tpu gasket deform and leak? how many cycles it would survive, if any.

[@CS-ym8mx]

You can add a drag knife or laser attachment to your printer and cut gasket that way as well.

[@theeddies]

I have a laser that I bought with my printer and never used it. Cannot seem to find the time to install it and learn it. The printers never stop, lol.

[@SianaGearz]

Amorphous, non-crystalline polymers are above glass transition temperature in normal use. I'm not quite sure what particular temperature you're looking for. Maybe heat deflection temperature?

[@theeddies]

Yes, I need to correct this in the next video (soon). I had this conversation with someone else and I decided that what I was measuring was likely heat deflection at zero load or basically when it starts to lose shape with no extra forces acting on it or right as it starts to melt. My testing says that is around 170c. But under load it happens much lower. Basically it would hold up a bolt torqued in my jig at 20ft lbs at 120c but that is really pushing it. Useable is still going to be a maximum somewhere in 100c range +/- for any usable torque range that I commonly use. If you are interested I will cover that in the next video as well as the effect of heat treating or annealing to increase its usable temp range. Thanks!

[@wktodd]

Interesting. I know pla will anneal or re-bond if heated to near the glass transition temperature and will then withstand slightly higher temperatures. I wonder if the same is true of tpu?

[@theeddies]

There is Bill bringing it with another test, lol. From my research on what little is out there it may be possible to get a bit more heat resistance by annealing it near the glass transition for several hours. Interestingly one article suggests that it will naturally anneal somewhat over time at room temp though the effect is slight. This stuff is alive. Possible drawback is it may harden as well. I need to come up with some way to test this I guess. I need a Shore Durometer.

[@theeddies]

Hello Bill, did you happen to see Stephen Gotteswinter video a couple days ago about tailstock drilling? He used a tiny coax indicator in it that I had never seen. Interesting design. Yours is more elegant though :-) Best! Eddie

[@wktodd]

@@theeddies hi Eddie, yes. You've just reminded me that I was going to take a closer look at it !8-)

[@tomspettigue8791]

What about doing this with a clamp tightly cinched down on it?

[@theeddies]

I did torque testing in this one kzbin.info/www/bejne/l5DJgmZmeLSEh5Y

[@hamood1234fool]

Can you please do this experiment? 1- Make a head gasket using TPU 2- Torque the bolt while the engine head is cold 3- Manually heat the head to 200c 4- Torque the bolts while the engine head is hot (perfect squeeze of TPU super seal) 5- Check for compression + run the engine for an hour.

[@theeddies]

Will not work. I have a video coming out in a day or so which will demonstrate it. But essentially at around 170c the gasket will start to melt and by 200 it will be running out, it will never hold any torque at that point. I could not get it to hold 15 ft/lbs at 170c You will be squeezing it out until you are left with metal to metal. Thanks! Eddie

[@whtkngofc]

TPU is hygroscopic like most 3D printed materials after printing . It will absorb water from the air and swell if left long enough .

[@theeddies]

Yes, I usually put it back in a bag after printing but I actually accidentally left this brand out for 2 rainy days and it still prints fine. Of course you can always dry it in the oven if it does get wet.

[@theeddies]

@Made By Nobody Famous Possible. Though I will say from my experience and from watching a few others investigate the hygroscopic nature of a bunch of filaments, I think this effect is overstated a bit. I know it can cause problems in the printing process, I have seen it cause popping and globbing problems with PETG but the amount of actual expansion both in weight and size is so small as to be nearly negligible. Thomas Sanladerer did some interesting tests with soaked filament and had trouble even measuring the difference between wet and dry in the real world. Again, I know it is hygroscopic, I am just not sure apart from the printing quality and (possibly some minor strength considerations in rigid plastic) that it makes much difference. Best!

[@johnstrange6799]

Not perfect for all applications, but still an impressive material for many applications.

[@theeddies]

Yeah the temp range narrows its uses quite a bit.

[@raybonz7939]

Saw your previous video an believe you were going to leave that carb gasket between the engine and carb for a while and see how it held up.. Have you done this and what were the results?

[@theeddies]

Still going good. I think I am up to around 10 hours on the machine over 8 mows including a few at outside temps above 90. I will have a follow up some time in August where I will take all of them off and take a look. Besides the carb gasket there is a fuel cap gasket and valve cover gasket. You can find those in the other videos. There are 5 in total. Thanks!

[@jamienoel]

​@@theeddies Is this between the engine and breather tube or breather tube and carb? I'm curious how it would hold up against the engine itself?

[@theeddies]

@@jamienoel Carb and intake manifold. I have another that is between the valve cover and cylinder head. It will get the hottest.

[@caesardgreatest]

Glass transition temp (GTT) is where it becomes elastic, so for TPU is way below room temp that's why it's flexible, below glass transition temp is where it turns stiff, solid, and brittle like glass. The temperature from solid to liquid is the melting point (MP), which sometimes comes in a range and not exactly points. What you're essentially measuring with the stretch test after heating with a torch is called the heat deflection temperature (HDT), which is it's resistance to alteration under load at an elevated temperature. TPU thermal characteristics are as follows: GTT: -24 deg C (that's below zero) MP: 220 deg C HDT: 74 deg C at 66 PSI Also, how are the gaskets holding up? It's been over a year at this point right?

[@theeddies]

I just did a a follow up - I will send you a link in a separate comment but links are not always delivered. If you don't get it, it is the latest video on my channel. As to your other points I actually corrected the nomenclature in a later more in depth video. Thanks!

[@theeddies]

kzbin.info/www/bejne/o3yUgGNoo51pfdE

[@caesardgreatest]

@@theeddies that answers that! Glad to know it all held up. Really when it comes to comparing to commercially available gaskets and o-rings, TPU is similar if not slightly superior to Buna-N.

[@santiagoblandon3022]

You can print too plasticized nylons or a softer nylon variant which are resistant to oil, fuel and have better temperature resistance than common TPU

[@theeddies]

What is the "softer nylon variant"? Most available nylons I am aware of are not going to be flexible in compression without maybe some clever infill design. I have not printed any yet, though my one printer should be able to handle most of the commercially available products I have seen. So am open to any suggestions. If there is one with Shore hardness in the A range, that would be a much better alternative. Thanks!

[@santiagoblandon3022]

I was thinking of Taulman, their PCTPE (which is a plasticized nylon) and their Nylon 645 which is quite soft. Also you could try some of these "easy nylons" most brands have. If you put them in hot water for a while, as nylon is hygroscopic, the water molecules get in between the polymer chains and plasticize it, turning it very soft.Although I could imagine that in a hot environment it will dry out and become hard again. There is also the polypropylene option which is very temperature resistant and it is as chemical resistant as you can get besides PPS. Formfutura and 3DXTech have PP, but I'm sure other brands too. Thanks for making videos on the topic :)

[@theeddies]

@@santiagoblandon3022 Thanks for the info, I will check them out. I have been wanting to try Nylon. Need to get or build a dryer. Best! Eddie

[@FriendshipLights]

So how does it work in an actual engine? That would be the great test

[@theeddies]

My latest video is the conclusion after one year.

[@theeddies]

kzbin.info/www/bejne/o3yUgGNoo51pfdE

[@FriendshipLights]

@@theeddies awesome

[@daliasprints9798]

If you look it up, the glass transition of TPU is actually below room temperature, even below freezing. This is part of what makes it not experience the warping PLA does when crossing Tg and cooling again.

[@theeddies]

That's actually very right. It would need to be solid (in this case frozen) before it can transition, so it has a long transition to liquid but starts at -42 is the number I am seeing. I used the wrong term in this case, thanks! I guess the term here would be its heat deflection at zero load. The point at which it will begin to lose its solid shape and become deformed. Would you agree that would be accurate?

[@daliasprints9798]

@@theeddies I'm not an engineer or material scientist but it sounds at least roughly right to me.

[@IceRhino44]

I swear I listened to you say "Multimeter" about 8 times. I'm gonna start saying it like that from now on

[@theeddies]

You mean mul-tim-a-ter instead of mul-tee-mee-ter? I have no idea why I say it that way. It just sounds better to my ears. Like altimeter is not all-tee-mee-ter. Welcome to the exclusive club, lol. Of course I just looked it up and apparently common UK pronunciation is mul tee. But most Americans say it that way as well it seems to me

[@joeking433]

Doesn't really make sense to me. Multi and meter are two defining terms brought together as it's a meter but it does multiple things. You would want the "meter" to be pronounced as the noun it is.

[@theeddies]

@@joeking433 I cannot tell you if it is right or wrong by the varied laws of English pronunciation, it is just the way I have always said it. It sounds better to me, it rolls off the tongue,, same with al-tim-eter. But I also don't say am-ah-ter for ammeter I would say am-mee-ter like everyone else I guess. As a side note I also say irregardless which really bugs some people. I had a minor in English Lit in Uni with a special emphasis on the works of James Joyce who also loved to mess around with words. If it is understood and I did not make it up it is fair game as far as I am concerned.

[@Sgtfroso1]

i think this is funny what engine are you running over 100c consistently you’ll worry about other things failing before the TPU does!😂

[@theeddies]

The lawn mower I tested these on would reach oil temps in the mid 90's. celsius during the last summer of 97F days. The TPU can take it, without failing but it is just on the edge.

[@severinleuenberger8336]

Has twezers still picks it up with his Hands hahahahahahah

[@grubbin6432]

I hear TPU is water sensitive. I hear it can absorb moisture.

[@theeddies]

All plastic absorbs moisture. TPU is certainly more sensitive to it but in my experience this only effects printability. The amount is so little it does not seem to make much difference to the part after printing. This is my experience and based on the some other results I have seen/read and all plastics react differently.

[@pr00009]

id say yes. sort of

[@theeddies]

I think you may find my coming follow up video a little surprising.

[@Ragnar.Lothbrok.3.14]

Find out what the glass transition temp is from the manufacturer and don't exceed that.

[@theeddies]

For certain higher end manufacturers that may work but I doubt most will have that info and different batches may have different temps. Most of the filaments I use have manufacturer recommended printing temps with a +/- of 10 or 15 degrees. If the glass transition has a similar spread I would rather do a quick test myself just to verify.

[@Ragnar.Lothbrok.3.14]

@@theeddies you might be surprised unless you're getting all your filament from China and there's a language barrier. The Tg temp is a pretty important one for any manufacturer. The print temps would be the melting temp (Tm) and that will be much higher than Tg

[@theeddies]

​@@Ragnar.Lothbrok.3.14 Most of my filament I am getting is Chinese made. I tend to buy from a few brands that I trust their consistency though. Like Duramic, give their TDS on their website. This is a brand I had never used but was running a deal so I gave it a shot and am pleased with it so far. I think it is called Rambery, lol. I will check with them and see what they say. Thanks!

[@edwardchristie3934]

Where is the fire?

[@theeddies]

You did not see my temp wire fire? 😁

[@cricketol]

torquing it between two plates and put it in a oven at 200 F to see what will happen

[@theeddies]

kzbin.info/www/bejne/l5DJgmZmeLSEh5Y

[@q9260]

Buy a sheet of gasket paper and cut out the gasket you need. Will save you a ton of work and repairs.

[@jack0cat]

I’m sure the gasket will not go anywhere in use especially for a water pump gasket it will never see them kind of temperatures in reality. Unless the engine is about to blow up. 🤣

[@1marcelfilms]

Submerge it for a year

[@antagonizerr]

Well here's the thing; You already know the absolute melting temp is 200 degrees C so it goes on to suggest that operating max is 50% of that. No 'experiment' needed chum.

[@theeddies]

Hello, I am not quite sure how you came up with that 50% calculation. Firstly, the melting point is lower than 200C. 200c is liquid enough to squeeze through a nozzle but it begins melting before that at around 170. My testing here as well as further tests which are coming show the gasket still performs well above 50% of "melting point" possibly even up into the 120C range. But it also depends on what pressure is put on the plastic gasket as this will effect its melting point slightly as well as its overall performance. There is also the effect of heating and cooling cycles effecting overall performance. Etc. I would argue there is plenty to test.

[@antagonizerr]

@@theeddies The 'actual' melting point of TPU is 145 degrees, not 170. But that's not even the point. The point is that it's the 50% tolerance rule in engineering. If the pressure point is 2000psi, then the operating pressure is 1000psi...if the weight capacity is 500lbs, then the operating weight is 250lbs. So I actually overestimated. Since the actual melting point of TPU is 145, then it follows that with the 50% rule, that operating temp should not exceed 72.5 degrees C. No actual testing needed. The melting point is a fixed variable, and the 50% rule is a fixed variable. You can, however, test for chemical resistance, but even that is a known, known. We know that TPU is not resistant to acetone because it's often used in smoothing and if you look at the data sheets, you see a list of other reactive chemicals.

[@theeddies]

@@antagonizerr The melting point is exactly the point, you don't even know what it is other than what you have apparently gleamed online, yet you are basing your 50% rule on it. There are no absolutes to be stated here as the formulation of the filament makes all the difference. Further my actual tests showed it can handle 20 psi of torque load at 120C (see latest video). The 50% rule of engineering is fine but we are not talking about a steel beam holding several tons of weight. We are talking about a flexible gasket holding a few PSI of air or oil pressure. It is likely not a problem but it also needs to be tested. There are countless papers (albeit behind paywalls) testing and confirming various TPU formulas, modulus, Shore, etc. Do you think they should just all use your calculations (200c or 145c) or whatever you read on a forum? I am doing these tests to satisfy my own curiosity and if someone quotes them somewhere on the internet I will be the first to say, "do your own testing before proceeding". And again not all TPU, just like not all PLA is the same, Just because one reacted to acetone, does not mean another will. I showed on video (2nd one) it had no effect on this brand but did effect the PLA I used. Other people say their PLA was not affected at all by acetone. Brand and/or formulation makes a difference. Dealing in absolutes is not helpful in this case as there are no real manufacturing standards at the hobby level as of yet. I cannot even get the company to provide me with a data sheet or tech specs for this brand. If I was buying engineering grade A1 tested material for 100's of dollars with known knowns I would use them but it is not the case here.

[@antagonizerr]

@@theeddies Lol, yup you're right and the data sheets are all wrong. Guess we should all just say, 'screw the manufacturer what do they know?' and just listen to you.

[@theeddies]

@@antagonizerr Since you just replied with some gibberish that states exactly the opposite of what I said in my previous comment, you clearly did not read the comment or understand it. Either way, have a good day!