Glue stick for PLA

[Jin Choi]

Glue stick has come up here often. Many people find it great (as I do), for others it doesn't work so well. I have some new observations on its use.

There are two reported downsides to glue stick: it goes on gloppy and thick, and it sticks too well for PLA making it difficult to remove parts. I think I have the same solution for both issues.

The glop issue, I believe, is caused from trying to apply to a heated bed, or from residue from previous prints. If you have this problem, try only applying when the bed is cold, and wipe down the plate with a wet paper towel. Usually I let it dry off before putting down glue. It was when I got impatient that I observed a potential solution to the second issue.

If you apply glue stick to a damp glass plate, it goes on light and slick, and when it dries there is just the lightest film on the bed. For PLA, which doesn't shrink much, this turns out to be much better than a full throated dry application. First layer adheres like a champ, but it doesn't require prying or freezing to get off. PLA doesn't require much adhesion, and will print just fine on a squeaky clean glass plate, but I find it tiresome to be cleaning it all the time.

[jimc]

Im glad you posted this jin. I almost forgot, i tried the glue stick again the other day. I applied one coat on a cold plate like you said. I was printing abs though. It was the elmers purple one. I couldnt even make it past the first layer. It might as well been a stick of wax. The lines of plastic just fall iff that stuff....i dont get it. Some rave about and other have problems but i dont see how there could be such a big defference. Maybe abs had something to do with it but ithers have said how awesome abs sticks to it. I cant figure it out :/

[Jin Choi]

That is a poser. I don't understand how you can be having such a different experience using the same glue. I found it even better for ABS because there were no issues with detaching afterwards.

One thought is, I noticed your temperatures all tend hotter than mine, both at the extruder and at the bed. Perhaps there is something in the chemistry that makes the difference between 100 and 110C. ABS glass transition temperature is 105, so maybe that has something to do with it.

My only suggestion would be to try more than one coat, drop the bed temp to 100, and then give up when that fails.

[Steve T]

I've also had great results with the school glue to a cold plate for PLA but terrible adhesion with ABS (cheap) even when applied to a cold plate, then heated to 100c, 235c @ nozzle. Although the Aqua Net works excellent for my ABS, hot or cold plate. I have a hunch its due to the differences in the ABS chemistry. If there's more of the component that helps with adhesion to the vinyl in the glue it will work great. Or as in my case just lower grade ABS.

.

[jimc]

i am going to do some more testing with it jin. its got me puzzled now which usually sets me off on a mission to figure out some answers.

[Toby]

i think i've just been converted to elmers.  i've been printing several long thin, curvy parts and on 6 prints got 2 failures due to curling on the plate, even with two coats of hairspray.  so i tried the diluted elmers approach (actually i'm using weldbond white glue but i assume it's the same.)  the proportions were about 1 part glue to 2 parts water, applied with a small paint brush and smoothed out with the roller.  

the three prints i've done on it all stuck beautifully.  after cooling they were still stuck firmly to the glass (unlike hairspray), but were removable by hand with a little force.  the key is the ability to dilute the glue.  i think this method is the surefire approach.  just do tests with glue at different dilution strengths until you find the one that works for you

[Levi8than]

I've had very good luck with elmers on PLA.  But no luck on ABS.

The glue stick is a little too strong for me.  I've had better luck with with 10:1 diluted liquid glue (I used elmers washable school glue) directly on the glass applied via a paint brush.  Apply when cold, allow to mostly dry before heating the plate.  If I heat the plate too soon, or apply while the plate is hot, rather than a very thin later, I get bubbles and brush strokes.  I store it in a mason jar and cut the brush so it fits inside the jar during storage.

For ABS the elmers didn't do much for me.  I've had better luck with the acetone + abs scrap slurry.  Downside is that if your slurry color doesn't match the color of the the abs you are printing, the bottom of your print gets discolored.  Direcly on the glass (washes off with acetone), or on top of the tape doesn't make a difference in my case.  Also, I don't store my brush in the bottle of acetone for fear of it dissolving. :)  And same story.  Apply cold and give it a chance to try.  If you apply hot you'll get bubbles and strokes.

[Sean Coston]

I recently printed a wall switch plate with PLA recently on bare glass at 60C and all of my corners lifted up.  I'm still a newbie, but have had several really successful smaller prints on bare glass.  Now considering going to the Elmers glue.  You apply the glue to a cold bed, but do you still heat the bed with glue to 60C for printing PLA?  Also, I had printed the wall plate with 100% infill (trying to make it as durable as possible).  I suspect that may have been a cause for the corners lifting as well -- the new layers going down and causing retraction on the edges slowly and incrementally.  Have others seen this with high infill ratios?

Sean

[Toby]

Yes, you still heat the bed to 60.  At least that's the way I've done it.

I've also suspected that higher density contributes to PLA warping.  It seemed counter-intuitive to me but maybe it creates more stress at the corners from the greater mass shrinking internally.  Also, the taller the model the more likely it seems for curling to occur at corners.

But that diluted elmer's is great stuff.  I think by adjusting the strength and making sure your bed level and z-height are good, you can eliminate curling in pla altogether.

[Bryan Boettcher]

If you were having successful prints on bare glass, why not stick with it?

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[Toby]

The problem was his larger print wasn't successful.

[Levi8than]

Even for large prints, I've had very good luck with elmers for pla.  As I wrote before, dilute to 10%, apply with a brush while cold, give it some time to dry before heating the bed.  This coating will last for 2 or three prints.

Removing your large prints may be a pain.  If so, I use canned air upside down it'll spay the liquid propellant out and cool the plastic faster than it cools the glass bed, so your part will just pop off.

Be CAREFUL with this, don't splash yourself in the face it could be VERY bad.