Recommended: McMaster-Carr adhesive PE film

After mentioning that I had trouble ordering from McMaster-Carr LoboCNC very kindly sent me a sample of their adhesive backed polyester sheet to try as a possible printing surface. The stuff is cheap (roughly $3 for 27x20 inches) which makes it attractive for the new large bed printer I'm working on - kapton gets a bit expensive as the area goes up, let alone pei or other exotic surfaces. However, it's rather thin at .002", and LoboCNC reported the adhesive failed in his initial tests, so hopes were not high.

So far though, it's been pretty good! I put the test sample on a piece of glass and used it with the small printer (the new build is nowhere near ready), and I've been using it exclusively for the last couple of weeks. It's remarkably tough stuff, I started off treating it very gently, but gradually got more 'robust' with it. I've even taken to using the razor blade scraper to get parts off and so far there's been no problems. I haven't pushed any prints right out to the edge of the bed, so it's possible there's still a weakness in the adhesive waiting to bite me, but there's been no signs of problems with prints up to about 1/2 bed size (standard 200mm bed).

PETG adheres easily to the surface, no problems with adhesion or removal. PLA also sticks well, almost too well at times depending on model footprint. There does seem to be a slight issue about the first couple of mm of each extrusion tending to curl away from the surface - I've lowered my first layer speed a little and also reduced first layer thickness and the problem is now mostly resolved. ABS was initially a problem, with several prints warping away from the bed. However, after gradually increasing the extruder temperature for the first layer to 255C there was a sudden jump in first layer adhesion, and ABS parts are now very reliable. The weak point is nylon - I haven't been able to find any settings that will get nylon to stick reliably to the polyester sheet. As a work-around I tested that I can successfully print nylon parts on a raft of either abs or petg, which for the amount of nylon I'm printing at the moment is a usable solution. If necessary I could experiment with adding a water soluble glue to the surface for nylon (since I know nylon prints well on elmer's purple), which I could then wash off again to get back to a clean surface. At the moment I'm enjoying the clean prints and low maintenance of not having any gunk on the print bed

So, on the plus side, cheap, robust, works well with most filaments, I'd say very good for petg, good for abs, reasonable for pla. Negatives are the poor performance with nylon and a question mark over the reliability of the adhesive, oh, and McMaster's strange reluctance to sell to non-residents of the USA. Can't win them all.

And since no review is complete without photos:

A couple of pla tests:


Initial lifting with abs


solved by increasing first layer extrusion temp:


I haven't been able to get nylon to stick directly to the surface, but printing on a raft of ABS works fine:


Thanks again to LoboCNC for enabling this test!

Sounds interesting! I wonder if polycarbonate is what the secret ingredient of Printbite is? It certainly seems to have a similar mechanic that the printbite has where the melted plastic needs to 'settle' into the surface texture of the material

After sending JamesK some of the polyester sheet, I did a couple of PLA tests of my own - first on a tiny 2"x2" square and then on a full-sized sheet. On the small square, I tried breaking off the PLA part while the bed was still warm, and the acrylic adhesive just pulled right off the back of the polyester, leaving a gooey mess on my bed. After hearing of JamesK's success, I tried out a full-sized sheet, again with PLA. This time, I waited for the bed to cool completely, but the part was nearly impossible to pull off. When I did finally get it off, you could see that the adhesive had pulled off the back of the polyester sheet locally around the edged of the part.

Now, I tend to print PLA really hot ~230c and with a bed temp of 70c. It could be that if I lowered both of those, it would work pretty well. Or maybe even just lower the first layer temp. In short, though, I think JamesK is right that this film is best for ABS and PETG.

I've also looked into getting some polyester film with a higher temp. silicone adhesive rather than the acrylic adhesive, but I haven't found a source yet for wide sheets.

Isn't that strange. I don't think it's the bed temperature that's affecting the adhesive since when I print abs I've used set temps up to 120C which probably gives me around 100 at the surface. I'm guessing that the glue is just inherently not that strong, and I've been lucky not to get a part so badly stuck that the force needed to get it off separates the glue. If it was parting between the glue and the bed I'd be thinking it was a surface prep issue, but when it comes off between the glue and the polyester there's nothing you can do about that.

If you wanted to stick with it you could try lower temps for the first layer to try and reduce the degree to which it sticks. I've been using 60 on the bed, and then dropping it to 50 for the rest of the print. Edit: At the nozzle I've been using 240C for the first layer and 200 for the rest in the most recent prints. I was using 235C, but I increased to 240C as part of my attempts to stop the first couple of mm curling up. The other factor is the first layer speed which I have set to 20 mm/s but often manually slow down on the lcd while I check that things are looking ok.

But if you print moslty pla it's perhaps not the ideal surface. What do you use at the moment? I have some kapton that I never got around to trying, but it seems very delicate. I can't imagine it lasting for very long, which could get a bit pricey as well as annoying. Elmer's works well, but it does make a mess of the print surface.

Edited 1 time(s). Last edit at 02/08/2017 09:09PM by JamesK.

Quote
JamesK
But if you print moslty pla it's perhaps not the ideal surface. What do you use at the moment? I have some kapton that I never got around to trying, but it seems very delicate. I can't imagine it lasting for very long, which could get a bit pricey as well as annoying. Elmer's works well, but it does make a mess of the print surface.

I'm using kapton tape, but I'm very careful with it so it's been lasting 6 months or so. If I've got a part I know is going to be difficult to remove, I'll design a pry-notch into the bottom.

Edited 2 time(s). Last edit at 02/08/2017 11:13PM by LoboCNC.

6 months seems pretty reasonable. Clever idea to include a pry-notch into the design.

Another way to get the part to release easily is to freeze it with Freeze spray.
Spray on the edge, and it cools down really fast, wait a sec and it comes right off.
Compressed air in a can held upside down also works, but then it is empty pretty quickly.

Also, if using compressed air, be careful as most of those cans do not hold air, but propane. Kinda flammable!

Pity that film is not easy to get here in Europe, at that price.

Quote
Lykle
Another way to get the part to release easily is to freeze it with Freeze spray.

That's a cool idea.

Sorry, couldn't help myself.

I should get myself a Feeze can, embarrassed to say I haven't owned one in probably 20 years. Not doing as much electronics as I used to. Fortunately I'm not having too much trouble getting parts to release now that I've dialed in the first layer temperatures and speeds a bit better. And the first test piece of the film is still holding up great.

It's frustrating when you can't source stuff at reasonable prices, I have similar problems with metal stock. Our American friends may not appreciate how lucky they are

Ha you made me laugh, once again.