White Glue and sandblasting for buildplate adhesion

[Stringman 2]

I wanted to pass along how our shop approaches buildplate adhesion with our four Ultimakers, after having used a lot of different methods.

First off, I roughen our glass plates. I was told to sand them, but I have access to a sandblaster down the hall. I go REAL EASY on this: a few fast passes with the sandblaster nozzle, turn plate 90 degrees, repeat, rotate 45 degrees, repeat, rotate 90 degrees, once more. I'm not trying to get every last bit of smooth glass worn away, I want to just barely frost or roughen it, evenly. Sanding would probably give you better control. Dust/rinse all the dust off the plate.

To prepare for printing, I get the plate wet, tip it for a couple seconds to let most of the water run off, then lay it flat. I grab my big bottle of white casein glue (Elmer's or similar) and dump a dollop about an inch across in the middle of the plate. Now I smear it over the entire plate with my fingers, mixing it with the water that's still on there, smoothing out any concentrations but not obsessing over getting it absolutely maniacally uniform. Set it aside and let it dry, which doesn't take long at all if you put a fan on it, or you put it on the heated buildplate.

This seems to give me excellent adhesion with almost any filament - PLA, PETG, nylon, Taulman 910 - those last two can be a real challenge - and yeah, sometimes ABS. Let a print cool completely and usually it releases very nicely (more on that in a moment.)

After printing and removing the models, I plop the buildplate in a sink of water to soak for a couple minutes, and then the glue can be scrubbed away easily with a pot scrubber or brush. While the plate is wet and clean, I grab the glue bottle and prep it for the next print.

Now, I used to use gluesticks on the rough plate, and that works OK, but it tends to build up if you don't clean it off every time. (I didn't.) I think part of why I'm getting consistent results with the Elmer's-Glue-on-wet-plate approach is because I'm removing the glue down to the bare rough glass after EVERY print.

For ABS, early on we caught on to the practice of either 1) dribbling some acetone on the buildplate and rubbing it with an ABS print fragment to create a haze/glaze of ABS plastic, or 2) I prepare some ABS/acetone slurry in advance and store it in old film canisters, ready to spread on the plate when I'm doing ABS. The stuff is messy and you need good ventilation, but it's really the only way I know to be super sure your ABS print doesn't lift. I used to only do this on smooth glass plates, but now I use the sandblasted sides for all prints.

Downsides: if you've had to pop a lot of prints off of your borosilicate glass buildplate, you've probably had chips pop out of the surface of the plate before. I think it is possible that sandblasting or sanding may make your plate more prone to spalling/chipping, but then again, I did buy a stack of cheap no-name buildplates from overseas, and I'm beginning to think they aren't actually tempered glass, so maybe that's to blame.

And while *usually* the white glue method releases quite easily, a few times it stuck so firmly that when I got my model off, it actually took some of the glass with it. Again, maybe my cheapo glass buildplates, I don't know.

Anyway, glue and sandblasting has been giving me really consistent results, such that I sometimes don't bother with printing a brim on models any longer.