UM2 "socks" - well it turned out to look more like spandex

[foehnsturm 967]

foehnsturm and tinkergnome

is the red silicone material I see just thin silicone sheet you punched a hole in for the nozzle and then attached it to the bottom?

 

Correct, it's 0.5 mm silicone sheet

[krys 206]

Hi folks,

Bump.

Is there any new news on this? The thread seems to have died mid conversation.

I am also interested in this, but I do not know where to start if I am going to DIY my own.

Was there a final verdict in what works best/easiest?

Any feedback would be much appreciated. Thanks!

[geert_2 431]

I tried the silicone socks with pushing on liquid silicone in a spoon (see pics above), but since that did not work, I dropped the concept.

Molten filament kept creeping in-between the nozzle and silicone, due to the pressure applied while extruding (especially when there is a little bit of overextrusion as on the first layers). The silicone was too flexible to prevent this. This molten material then perforated the silicone near the top, so that the melt spilled out at very undesired places.

So I removed the silicone again, and now I keep the nozzle clean by wiping it with silicon oil prior to printing, and immediately cleaning it after each print with a paper tissue.

[krys 206]

So I removed the silicone again, and now I keep the nozzle clean by wiping it with silicon oil prior to printing, and immediately cleaning it after each print with a paper tissue.

 

Silicone oil is an interesting idea. Hmm...

It got me wondering about some kind of silicone or whatever wiping cloth/thing. Something where hot plastic would prefer to stick to it and to brass/steel(/ruby), but maybe when cold, then plastic does not want to stick anymore. With a specialized wipe instead of paper tissue, maybe the oil/sock/sheet would not be necessary. It would have to be heat proof of course.

Then again, that would not address the curling aspect.

Anyway, thanks! You got me thinking in an interesting direction!

[geert_2 431]

The curling is greatly reduced - but not eliminated - by wiping the nozzle with silicon oil. The kind of oil that is also used for lubricating car door rubbers in winter, to prevent them from freezing up, and similar. I found it in a car shop.

The filament still starts to curl, but since it sticks less to the nozzle due to the silicone oil, it tends to fall back down soon.

For wiping I use a sort of quite strong paper tissue, as used in laboratories. I don't know the specs, since it is old, and I don't have references anymore. But any strong

and rough paper tissue should do, I think.

[foehnsturm 967]

Molten filament kept creeping in-between the nozzle and silicone, due to the pressure applied while extruding (especially when there is a little bit of overextrusion as on the first layers). The silicone was too flexible to prevent this. This molten material then perforated the silicone near the top, so that the melt spilled out at very undesired places.

 

That's more or less the issue with all silicone sock variants, even with the E3D one as far as I can see. It's difficult to make them thin AND rigid enough around the hole. I did some experiments with fiber enforced PTFE adhesive, which is insanely strong, even with thicknesses of 0.5 mm and below), and really non-sticky. But if you punch a hole the fiber ends will start to fray over time. If this can be solved it would be a very interesting alternative.

[krys 206]

That's more or less the issue with all silicone sock variants, even with the E3D one as far as I can see. It's difficult to make them thin AND rigid enough around the hole. I did some experiments with fiber enforced PTFE adhesive, which is insanely strong, even with thicknesses of 0.5 mm and below), and really non-sticky. But if you punch a hole the fiber ends will start to fray over time. If this can be solved it would be a very interesting alternative.

 

I am reminded of those adhesive rings you could get for 3-hold paper to fix broken holes.

What about some kind of high temp, high-ish shore value, reinforcing ring adhered around the hole to reinforce the fibers and give them a fixed/protected end point? It would have to be really thin though, and the adhesive would also have to be high temp.

I am not materials guy, but a reinforcing ring seems like an obvious first thought. I guess the devil is in the details.

Anyway, I am glad you folks are exploring this topic. I guess the idea is just not fully baked yet.

Keep up the really insightful work though!

[krys 206]

... Or, is there just a silicone/something coating we could just dip/coat the nozzle in?  If it is bonded to the metal, then there would be no seam for plastic to push under.

Some kind of silicone oil but with an adhesive?  I dunno, just thinking out loud.

Something less mechanical and more chemical?

But then again, non of this is wiper related.

[Labern 760]

The Nozzles could be coated in PTFE like what they put on non stick frying pans.

It's not an expensive process to get done.

[krys 206]

The Nozzles could be coated in PTFE like what they put on non stick frying pans.

It's not an expensive process to get done.

 

That is an interesting idea. I wonder if anyone has already tried it and/or figured out why it is a bad idea? I.e. I wonder why it is not already commonly used?

[Labern 760]

Yeah I have only been thinking about trying it for over a year now but not got around to actually doing it. There is a company not far from my place that does it. We used to use it in in the last campany I worked in. It's a slight insulator as well which I found at 200 deg the Teflon surface was about 20deg cooler. This will help stop the fans effecting the temp slightly.

Just like frying pans it is susceptible to scratches but I found the industrial coating stronger.

Good thing is you can have it recoated if it gets damaged.

[krys 206]

It would be cool if we could find a DIY way to do it, but I suppose getting it professionally done first as a proof of concept would be good.

Also, max temperature support would have to be a consideration. Some of us like to print @ 300C.

And lastly, if the coating did not completely cover the nozzle tip, say 0.5mm away from the hole, for example, then I do not think we would have to worry too much about damage. Just no more Scotch Brite (sp?) or steel wool for cleaning. Oh, and no coating around the driver/wrench contact area either.

Anyway, those are the thoughts your words triggered in me.

[Labern 760]

Yeah I was thinking the same.

It's easy for them to only coat a certain area. It's sprayed on then baked at high temp in a oven to cure it. It can withstand 300deg as we used to use it at that temp.

So to do a nozzle, you just need to cover the area's you don't want coated. This could be done with a small jig.

A diy process would be great if it did work.

[krys 206]

Yeah I was thinking the same.

It's easy for them to only coat a certain area. It's sprayed on then baked at high temp in a oven to cure it. It can withstand 300deg as we used to use it at that temp.

So to do a nozzle, you just need to cover the area's you don't want coated. This could be done with a small jig.

A diy process would be great if it did work.

 

Cool! Well, if you ever decide to pursue this idea, I will buy a nozzle or two off of you and alpha/beta test them for you.

No expectations, of course.

[geert_2 431]

Forgot to mention in my earlier post about silicone socks: another important thing with a silicone sock is that it may have a high friction (like most silicones), and it may rub off the first layer from the glass. Otherwise, using a strong adhesive silicone like Tec-7 might have been an option.

Concerning PTFE, I have tried PTFE oil from a spray can. Sprayed it on a tissue, and then wiped the nozzle. But that doesn't get baked on, and it does not stick to the nozzle. It actually gave worse results than wiping the nozzle with a tissue with silicone oil. I have no idea what baked-on PTFE would do; this could be an interesting experiment.

[rowiac 50]

For DIY coatings, Cerakote C-100 Micro Slick Dry Film Coating looks interesting. This is an air cured low friction ceramic coating used on vehicle engine parts, so it can withstand high temperatures.

Might be worth a try. Not sure if it's available outside of the US though.

[Labern 760]

Pla sticks to Ceramic

[foehnsturm 967]

@Labern,

you have a company nearby doing this, that's great! Curious about the results.

I always wanted to try this. Even wondered why no one is trying this for surfaces inside the hotend.

[Labern 760]

Yeah.

I will try to make sure I get one coated soon to test.