PEI print bed surface experiments

[mhackney]

I haven't determined that the gasket cement works yet! I'm going to try to pick up a can tomorrow and give it a shot.

The thing that I'm printing is a 200mm diameter flying disk of my own design. An interesting little bugger. And, it test the heck out of your printer setup and calibration too!

I'm still deciding what I want to adhere the PEI to. Either the aluminum dissipator itself, the glass or a separate piece of aluminum. I'm leaning towards the glass so I can just flip it over and use either glass or the PEI and I'm not sure how long the stuff will last. And the glass is nice and flat.

[Eaglezsoar]

Another option is a high temp adhesive that stays tacky and can withstand 500 degrees Fahrenheit.
It's called Permatex 80064 High Tack Spray-A-Gasket Sealant. I think I am going to go with it. Sounds like it will allow removal
of the PEI if you need to in the future. Spray the glass apply the PEI and maybe a small roller to smooth it nice and tight to the glass.
Only found 4 oz cans but that should be more than what we need. Amazon wants $9.41 with prime shipping.

[Batteau62]

With all the substrate experimentation you've been doing lately. I think you need to design and build a nice round vacuum table.(In your spare time of course ) Make it out of aluminum, could replace the heat dissipator

[mhackney]

I'd love to have a vacuum table for my milling machine! It's a great way to hold down fixtures. Noisy though.

I saw a big 5'x10' router at a sign shop recently that uses 3/4" particle board as its bed. I did not realize how permeable PB is! They had a big vacuum pump that pulled a vacuum below it. You could not pry off a 12" x 12" piece of plywood lying on it with the pump on. That was impressive.

[Batteau62]

I used to make them out of 1/2" acrylic at a specialty ad company I worked for. We used them to silk screen on. I have a lab pump. I use it to de-air castings/molds, it's fairly quiet actually. The one's at the ad company were in insulated boxes to muffle them. If I can find some aluminum, for not to much, maybe I'll give it a try?

[mhackney]

It would be a neat thing to have! Imagine just laying a piece of paper down, turn on the pump and print. Turn off pump, take off print and paper, add new paper and print. That would save lots of time on every cycle! Mix in PEI, Garolite, or whatever you wanted!

[Batteau62]

That's the idea Just needs some implementation

[Eaglezsoar]

I forgot to ask, what is a flying disk?

[cope413]

Could be wrong, but I believe it's a disk that flies

[Eaglezsoar]

Could be wrong, but I believe it's a disk that flies

ROFLMAO!

[mhackney]

That's it exactly. 200mm Round so it's big. Here's a screenshot of the CAD:

I just got back from the reelmaking workshop I taught for a group of disabled veterans today up in Maine. Great event, good guys. They loved my 3D printed reel.

On the way home I picked up some of the Permatex copper spray adhesive. I sprayed a bit on some plastic as soon as I got home to test out. I think this just might work! It goes on nice and thin and is nice and tacky. You only need to keep the PEI from lifting. This might make it possible to peel up the PEI later to replace if needed. I am going to push forward and attach it to my glass plate and see how it goes.

[mhackney]

Ok, now we wait...

Here's the spray and a double coat sprayed on the glass. I cleaned the glass with isopropyl alcohol first and applied one thin coat and then a second thin coat perpendicular to the first:
[img]http://mhackney.zenfolio.com/img/s10/v1 ... 7448-3.jpg[/img]

Ditto with the PEI:
[img]http://mhackney.zenfolio.com/img/s4/v63/p55541356-3.jpg[/img]

The instructions say to wait until tacky (30 seconds) and then assemble. I checked the overspray to make sure it was nice and tacky.
[img]http://mhackney.zenfolio.com/img/s10/v1 ... 9770-3.jpg[/img]

Now I have it sitting on a thin plastic (HPDE) sheet on my granite table with another sheet of HDPE on top, and two sheets of baltic birch (3/4") plywood with about 100 pounds of weight on top. That's about 1# per square inch. The spray goes on quite thin and I don't think much pressure is needed to get good contact. I don't know if this stuff cures or stays tacky. I'll research the website. I'm going to let this sit over night and then trim off the perimeter on the band saw with a very fine tooth blade.

[mhackney]

Did I mention that the copper spray looks really purdy? It does!

[Eaglezsoar]

I hope that your spray works out for you I'm going to try the Permatex 80064 High Tack Spray-A-Gasket Sealant although it won't be as purdy as yours.
Should be here on Tuesday.

[mhackney]

Yeah, my only concern with it is that it might not "hold" at ABS temps and allow the PEI to move/curl (although there really isn't any curl in the PEI sheet). This gasket adhesive holds a gasket between two hunks of metal bolted together so that is not an issue in a car engine. A spray material that cures would be ideally, especially a sprayable RTV silicone or even one that cures at say 100°.

[mhackney]

As soon as I wrote that I said to myself "self, you should really google 'spray can rtf silicone' and see if you get any hits." Guess, what, first hit:

RTV Silicone Sealant in a spray can

It comes in several temp ranges - both good to 450°F/232°C - and one of them is CLEAR!!! I really have to get some of this to try out! I also wonder what it is primarily used for? Cool stuff.

[Eaglezsoar]

That will give you something to fall back on in case the other doesn't work that well.

[mhackney]

Yes, and it just looks like cool stuff I am sure I can find a use for!

[Eaglezsoar]

The .03 PEI can it be trimmed with a razor blade or scissors?

[mhackney]

I tried scissors and it is too hard/stiff and didn't want o risk cracking it.

[Cleveralias]

Hey folks,

Dropping in to share my experience so far.

I ordered the .09 sheet last week and returned home to it last night after some travel. I regretted ordering the thicker sheet shortly after it shipped, but I have it now and at last check we had cleaned out Amazon of the .03 stock, so I might as well play with it. I have a 12x12 sheet of Mic6 aluminum arriving in a couple days with the thought of adhering the (or a) PEI sheet to it. The .09 sheet, if it matters to anyone, is smooth on both sides unlike the .03 sheet described earlier.

But I need to try this stuff NOW, so I figured I have nothing to lose testing PEI:glass with my magic glue stick. The glue stick is Elmer's Xtreme, which I've been meaning to mention as I haven't seen it come up and it works extremely (make your own pun) well. Parts stick to it very strongly - much more so than UHU or any others I've tried, and sometimes bordering on too well. If you're in the market for a glue stick, I'd highly recommend trying this one. Okay, so a nice coat of glue stick to clean glass and then I added a few drops of water and mixed up the glue to a thick paste, affixed the PEI, and left it with some weight on it for a couple hours. Then a couple cycles of heating to ~55* and kneading out any bubbles and I'm good to go. Probably would have been easier with a thinner sheet.

I tried printing in PLA first and man am I impressed! I made a thin, flat part roughly 75mm in diameter. It's a part I would definitely have used a brim for normally, for insurance if nothing else. It stuck perfectly. I got impatient waiting for the bed to cool and the part to release, so I turned my can of compressed air duster upside down and gave the part a .5 second blast. It ejected immediately!

Next I wanted to see what would happen at higher bed temp, and this is where things break down. I set the bed to 105* - I don't print that hot, but I wanted to see how it'd behave. The answer is not well. The glue probably softened up some and the thick sheet wants to warp significantly at that temp, and so it did. I would like to see if a thinner sheet would stay stuck at that temp if I get a chance.

So I'm going to go print some PLA I suppose. I think I may end up ordering a thinner sheet for whatever route I decide to go ultimately. If anyone has an idea for the thicker sheet and wants to experiment vicariously, I might be open to requests.

[Eaglezsoar]

I bought the .03 sheet of PEI in a 12 X 24 sheet. Has anyone figured out how to cut this stuff?
I want to cut the sheet in half but not sure how to do it without cracking it. Any ideas are welcomed.

[mhackney]

You can score and snap straight "cuts". It also cuts well with a very fine tooth bandsaw blade. I suspect a small diameter router blade with a template bearing could be used to cut circles.

[Eaglezsoar]

You can score and snap straight "cuts". It also cuts well with a very fine tooth bandsaw blade. I suspect a small diameter router blade with a template bearing could be used to cut circles.

Thanks for the info, I think I have the template bearing bit, that sounds like the best way to do the circles as long as I am careful.

[bubbasnow]

As soon as I wrote that I said to myself "self, you should really google 'spray can rtf silicone' and see if you get any hits." Guess, what, first hit:

RTV Silicone Sealant in a spray can

It comes in several temp ranges - both good to 450°F/232°C - and one of them is CLEAR!!! I really have to get some of this to try out! I also wonder what it is primarily used for? Cool stuff.

how is the glue working?