Can we print it SOFTER? TPU experiments.

Following up on the first 4 videos in this series, in this one I explore whether or not it is possible to 3D print softer gaskets using TPU or flexible filaments. If you have not seen the rest of this series check out the links to see my attempt to test the limits of printed TPU in semi-scientific tests and in the real world.
The first 4 videos of the series:
Can you print 3D gaskets? Should You? - • 3D printed gaskets? An...
Will 3D printied gaskets melt? - • Will 3D printed gasket...
Can you heat treat 3D printed gaskets? - • Annealing TPU to incre...
3 ways to design a gasket for 3D printing - • 3 ways to design a gas...
Tools used in this video:
Sovol SV01 -amzn.to/3LwYxN0
TPU Filament I used - amzn.to/3RV0vLC
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 chapter:
00:00 Intro - comparing infills in TPU
00:38 Intro - why I am doing this test
01:55 Testing paper gasket hardness
02:52 Why a softer gasket?
04:25 How to 3D print TPU softer
05:38 Results of tests
06:20 Infill and walls considerations.
08:40 The finished valve cover gasket and printing specs
10:04 Gas (fuel) cap gasket
12:04 Long term fuel testing
13:08 Install of both gaskets

[@GABSPACE]

Perfect, thanks for turning your research into a video, saves us all some testing time.

[@theeddies]

Thanks!

[@overlord8880]

May I suggest adding a bolt, a nut, and two washers to the corner piece in gasoline jar? Just to give that extra simulation factor and to see if the are deformation, stickiness or tearing issues when you eventually remove it. Torque it to whatever Torque you feel is equivalent to your application. Great series on the gaskets by the way.

[@theeddies]

Sure I can do that. Thanks!

[@danharold3087]

On gaskets like this valve cover we can print thicker to to get more squish. I did not have much luck with the paper gaskets on that valve cover early on. Switched to RTV only. Looks like your having good luck with just the TPU gasket. This is great for setting valves where on has to install and remove and install the cover. Will be trying it soon.

[@theeddies]

That was my thought. I got this mower free because the valves had never been adjusted on it and it bent a push rod. I kept meaning to order or make some paper gaskets. Because it is hit or miss whether they tear every time you take them off and on. Best!

[@ABG_3D]

Thanks again for a great video 💪🏽 Keen to see the results of the valve cover gasket after a couple of weeks, however I doubt it will see pressures in excess of 14 psi. Will still be great to see the end result after a couple of mowing days though. I also started designing my own gasket for the throttle body application I mentioned previously and printed one in SBS to have a physical model in hand and testing my measurements while I await my TPU to be delivered. I might run into some extrusion issues though because I'm using a bowden style printer (Ender 3 v2) with an upgraded hotend, but sure I'll find a way around it. Submerging tpu in fuel will ultimately change the properties of the printed part in the long run yes, however by that time you can just print a new one and replace it, it's cheap enough 🤣

[@theeddies]

If I come up with a method to do a pressure test and have the time to do it I will give it a shot. I believe you said that the original gasket was paper? If so, I would go out on a limb and say the tpu printed 100% is going to hold up beyond the capabilities of paper. I am not sure what the fuel is going to do. My guess is it will have some minimal effect of like the one I tried for a couple days did. Curling up. I really doubt it is going to dissolve it or the like but you never know till you try.

[@ABG_3D]

@@theeddies Would be interesting to see what you come up with if you do decide to perform pressure testing as this will open up another can or worms for sure. That is correct yes, it is a paper/carton gasket, but after being torqued to 18ft/lb it lasts up until you remove the throttle body again 🤣 I agree with you here, this is really an unknown factor of what will happen, however, in my mind the worst that can happen is curling and a slight change in overall dimensions as per one of your previous videos. I think I will also do a fuel test once I have received my TPU by dumping some printed TPU parts in a container and top it off with some of our premium 95 octane fuel we have here in South Africa and I would need to find some ethanol (E85) to test with that also to be entirely sure. Thank you once again for your video's, you have sparked my interest 💪🏽

[@johnstrange6799]

When you consider how many methods and types of materials man has used to make seals, packing, gaskets, insulation, adhesives (and more) over the years, then TPU stands as good a chance as any of becoming another accepted gasket material option for certain applications.

[@theeddies]

I sure hope so or I have lost a ton of money investing in polyurethane futures on the commodity market :-)

[@theeddies]

Damn man, all the recent conversation threads are gone, lol. I had to come to an old video to find a comment by you to respond, lol.

[@johnstrange6799]

@@theeddies Well, at least you know I'm worth it. #Thiskidisgold lol

[@johnstrange6799]

@@theeddies You have any older music software sitting around?

[@theeddies]

@@johnstrange6799 Not that I can think of. I had an old ProTools and Cakewalk Sonar but last I tried to use them, they would not run on some previous Windows I had so I trashed them. They were hacked software anyway, lol.

[@nsmith0723]

have you tried using a much larger wall thickness?

[@machinenutdel6764]

Hi Ed. more excellent research, are the paper gaskets just paper, from my limited experience I seem to remember them having some form of coating ?

[@theeddies]

Yes, good ones are a mix of materials not strictly paper. more like fibers mixed with other compounds. I have just always referred to them as "paper gaskets" in general terms.

[@daliasprints9798]

While you're on the topic of TPU parts, have you thought about experimenting with TPU bushings for suspension parts? Commercial ones are often made out of very similar PU materials so I think there's a good chance it could work.

[@theeddies]

I have thought about it. I have been trying to come up with something to try it on. So far I have an over travel bumper for the front suspension on my truck that needs replaced. It is a big piece but not critical so that if it fails I still have a drivable vehicle. It is a bit involved to remove it so it will be a little while to get there. I have gotten some comments about people using it for the bumper in a motorcycle shock with success, that is also a possibility. I will come up with something eventually. There is no reason I can think of why you could not make perfectly usable suspension bushings with it, I just do not have the right use case right now. Though thinking about as I am writing I am wondering what kind of bushings if any my mower has in the steering linkages. Poor guinea pig mower.

[@kirillbez386]

Hey, I am curious are you still using the original gaskets that you printed? Have you done any others?

[@theeddies]

I did three different gaskets. Fuel tank, carb, and valve cover. They have all performed without any issues. I had some personal issues over the last few months and have not made any videos but I plan to make a follow-up before the new year.

[@happywags1301]

Apologies if it was covered but is the fuel you are using ethanol free? I ask only because of how much of a trouble fuel containing ethanol can be on small engines.

[@theeddies]

Ethanol can be a problem. Zero ethanol fuel is hard to find/inconvenient around me though.

[@nsmith0723]

have you looked into cura's ironing feature?

[@danharold3087]

It also exists in prusaslicer

[@theeddies]

I have tried ironing, but not with TPU. I am not sure what larger wall thickness would accomplish for a softer gasket. Thanks

[@juliusfucik4011]

In my experience all of the typical materials used for 3d printing are very resistent to things you would think do at least something. For PETG you can immediately rule out any product that comes in PET bottle 😄 So far only aceton works, but that stuff in high concentrations is not something I want to work with much. Not even outside.

[@Robinlarsson83]

I'm considering using TPU gaskets and seals for a few different things on my boat. Perhaps for some covers in the Saildrive (so will be sealing against motoroil, at low temps). But I may end up just using NBR O-rings there since all the gaskets in the saildrive is made like that. But I also want to try making sealing profiles for hatches and opening windows, TPU should be perfect for that. I've actually talked with sealing profile manufacturers that offered TPU as an alternative to extruding EPDM, I think they still extruded it but not sure. They could do much small runs in TPU than EPDM or Nitrile for example. Back then (a few years ago) I has no idea you could 3D print TPU and TPE :) Finally bought my first 3D printer yesterday, an Ender 5 Plus, so will be testing that out in the coming days :)

[@theeddies]

Nice. If it were me I would give it a shot on the hatches, I might do some sun testing with your brand of TPU for the windows before fully committing, but it sounds like a great use and I would really only worry about color fade if exposed to long term sun. But I cannot see any reason it would not hold up as well as EPDM. Let me know your experience with the Ender. I will be trying it soon. Thanks!

[@Robinlarsson83]

@@theeddies yeah, the hatches themselves will cover the seals from UV, but as you say, on opening windows it may not. As far as I know, TPU should be fairly UV resistant, EPDM sure is at least :) But I'll do some tests for sure! And I can always print new gaskets if needed after a few years or so :) Started up the printer and it all seems to work (bought it very lightly used from a 3D printing company), but fairly noisy fans and stepper drivers. I may just upgrade the controller to something with TMC2209 or similar and add a Pi and run it on Klipper fairly soon :)

[@sidneyking11]

Could you create a gas cap?

[@theeddies]

Sure. I make a product I sell with similar threads that is for lathes. It is a pretty easy print upside down. One could replicate this design though it is patented by Kelch. As far as material, we will see how this holds up to the vapors, and I suppose ABS or ASA would be ok. Not sure about PLA or PETG long term with fuel, YET.

[@lizardking8388]

TPU gaskets seem to be a good idea for gaskets that aren't exposed to high heat. Ever try 3d printing a mold that could be used to make RTV gaskets which could then support higher temperatures?

[@Mrpurple75]

How do you print so fast?

[@theeddies]

Direct drive extruder and lots trial and error. It is really only running about 50mm/s for TPU though. It just looks fast in the video. PLA, I run about 75-80mm/sec for stuff I don't care about finish. It is not the fastest by any means but pretty good for what is essentially stock hardware.

[@workingTchr]

I'm looking at TPU for a vacuum seal gasket and, given it's importance, I'd want to use 100% infill so it's solid. The trick will be finding a filament that is soft enough at 100% infill.

[@theeddies]

95A TPU will probably be soft enough but there are some softer varieties of TPU as well. NinjaFlex makes one that is around 75 I think. Best!

[@wktodd]

If you want softer you might try foaming tpu (I presume it has a controlled moisture content ).

[@theeddies]

So you got me there, I had not seen that stuff before, might be a bit too soft. Interesting though, I missed the video by CNC kitchen talking about it. He also talks about the same stuff that I do in this one. SMH, I don't know why that video did not come up in my research. Now this one is just a cheaper copy. Oh well! Mine has a lawnmower though, lol.

[@psgflier]

Jeese, that's almost $5 worth of gas you're wasting on that test!

[@theeddies]

Don't worry I will just put it back in the mower when I am done. Dissolved plastic and all, if it comes to that.

[@edwardchristie3934]

Endlessly?

[@theeddies]

Endless TPU videos?