Cleaning glass so your parts stick

I'd like to share how I got PLA to stick to the glass on my heated bed. I was experimenting with different cleaners and nothing was working. I tried white vineger, mineral spirits, nail polish remover, straight acetone, windex, lemon, running the plate through the dishwasher, and scrubbing with a sponge and soap. No matter what I tried the parts refused to stick.

After much frustration I was looking online and found an article on cleaning microscope slides. This got me thinking that maybe the paper towels or rags used to clean the glass are reason the parts wont stick. My theory is that the cloth leaves a layer of lint / dust behind when you clean it and that is was prevents the plastic from sticking to the glass. No matter cleaner I used, the surface of the glass felt kind of slick.

So to test this I wanted to thoroughly clean the glass without using any paper towels or rags. I took the glass plate to the kitchen sink and placed it on a plastic cutting board about the size of the glass. First I gave it a good scrub with dish soap and the back of a sponge to remove any grease and dirt. Then, I soaked a paper tower with white vinegar and poured a nice splash onto the glass. I scrubbed both sides of the glass while it lays flat on the cutting board, and even wiped along the sides of the glass (the cutting board just keeps the glass from flexing when you scrub it). Then I rinsed the plate under fresh tap water to remove the vinegar. After that I gave the glass a good rinse with 97% rubbing alcohol on both sides. Lastly I placed the glass on its side, on a paper tower and leaned it against my printer to dry for about 15-30 minutes. The glass was very clean at this point and had no smudges or water marks. It also has that squeaky clean feel. So far my prints are sticking very well to my newly cleaned glass.

This also got me thinking that the reason stuff like PVA glue and the abs/acetone coctail work is because you brush them on and let them dry up. I guess the plastic forms a mechanical bond, but maybe they work because they are never wiped off with a rag or paper towel.

A couple of notes / common sense:
-Be very careful when handling your glass. If the edges aren't polished then they are very sharp and will cut you.
-Try to avoid touching the glass during and after cleaning with your bare fingers. The oils on your hands will keep your parts from sticking.
-Don't hold the glass while you scrub it- lay it flat onto a cutting board or something else flat.
-Don't use the bottom of your sink because that probably is not flat.

Edited 1 time(s). Last edit at 01/30/2014 11:01AM by stabbs.

Super interesting! I use paper towels to wipe on hairspray with VA/Crotonates/Vinyl Neodecanoate Copolymer (because I don't want to spray on the delicate machinery) and get excellent hold on PLA prints.

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ConceptFORGE
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I think that the layer you place needs to be very thin to work. thick layers will liley cause parts to warp because you are relying on the adhesion material for strength and it is flexible. very thin layers with excess wiped off likely have very little elastic properties and all the properties of material bonded to which is glass.

I've had better luck wiping acrylic on with paper towels and wiping excess off rather than letting it evaporate. I started making abs juice as well to try. that does not need to be wiped on thin. it works when on thick as well.

Edited 3 time(s). Last edit at 01/30/2014 01:27AM by jamesdanielv.

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jamesdanielv
I think that the layer you place needs to be very thin to work. thick layers will liley cause parts to warp because you are relying on the adhesion material for strength and it is flexible. very thin layers with excess wiped off likely have very little elastic properties and all the properties of material bonded to which is glass.

I've had better luck wiping acrylic on with paper towels and wiping excess off rather than letting it evaporate. I started making abs juice as well to try. that does not need to be wiped on thin. it works when on thick as well.

just to clarify I am printing directly onto glass with no coatings or treatments.

All this hard work

I use kapton and once in a while aceton to clean it.

The kapton on my ABS printer never needs to be cleaned and just works forever. The kapton on my PLA printer needs to be cleaned when I have printed on the same area for about 3 times, after that it starts falling off when I print on that area.

I know most people want to look for healthier solutions, but for me nothing has worked. Not even the lemon story I found in other threads (do I smell a troll there?)

stabbs,

are you using a heated bed? or is the glass at room temp?

Thanks

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NFireLabs - The World First Modular 3D Printer - At An Affordable Price!

Would acid etching the glass substrate be an improvement,
and has this been talked about before?

If the plastic does adhere well, it might be very difficult to remove.
I would think that would help prevent the edges from lifting, or warping.

One problem comes to mind, if the plastic grips the glass tenaciously it
might encourage spalling due to the object shrinking.

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ayouden
stabbs,

are you using a heated bed? or is the glass at room temp?

Thanks

I use a heated bed. I print PLA first layer at 55 degrees and drop it down to 46-50 for the remainder of the print

Quote
A2
Would acid etching the glass substrate be an improvement,
and has this been talked about before?

If the plastic does adhere well, it might be very difficult to remove.
I would think that would help prevent the edges from lifting, or warping.

One problem comes to mind, if the plastic grips the glass tenaciously it
might encourage spalling due to the object shrinking.

I have read many people have acid etched and sanded the glass, some with success and others without. The prints grip very well while the heated bed is on. When the print finishes and the bed cools down you can hear the part breaking free from the glass. I sometimes use a razor to pry the part up while the bed is still warm but you can definitely scratch or crack the glass doing this.

I use mirrored tiles from Lowes, and clean them with Ammonia based generic glass cleaner and wipe down with paper towels. I heat the mirror to 60-70°C and NOTHING lifts ever.

I would not be surprised if some paper towels have small amounts of surfactants applied to speed wetting and water absorption. These may interfere with adhesion. I have not had much luck with cleaning alone using paper towels either and it could be the brand I use.
But I'm very happy with glue stick so haven't had reason to investigate more.

edit: in fact there is a ton of stuff all over teh internets about surfactants in paper towels.

Edited 1 time(s). Last edit at 01/30/2014 03:09PM by swoozle.

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swoozle
I would not be surprised if some paper towels have small amounts of surfactants applied to speed wetting and water absorption. These may interfere with adhesion. I have not had much luck with cleaning alone using paper towels either and it could be the brand I use.
But I'm very happy with glue stick so haven't had reason to investigate more.

I hadn't heard of people using glue sticks. Are they the common arts & craft type sticks? How often do you need to reapply and do you use that with a heated bed?

I use a common washable glue stick (Elmer's?). It is purple and dries clearish.
I got the idea in these forums. Do a search on glue stick here and you'll find lots of info.

I usually have to reapply it every few prints but it wipes off easily with a wet paper towel and goes on quickly. If it is a particularly warp-prone part, a quick touchup between runs in the areas where the part is most problematic helps alot.
It seems to work better after it has been heated to about 100C.
I do use it with a heated bed both for ABS (110C) and PLA (50C). On cooldown ABS will pop off the bed on it's own. PLA usually does as well, sometimes needs a little tap. I've used it for nylon and t-glase as well with good success.