How to make a very sticky glass printing bed without any additive

thingiverse

The problem I tried to solve was that my new perfectly flat printing bed in borosilicate glass wasn't sticky at all for PLA filament. I didn't want to use sticker papers anymore because the rendering of the surface of objects in direct contact with the glass is so perfect! Then, I had an idea - cross sand one face of this glass sheet with 600-grit sandpaper. If thin scratches are almost invisible and not visible at all on printed objects, they immediately produce a huge effect, giving strong adherence to the PLA filament on the glass surface. I exclusively used this sanded glass sheet since then, and it worked great every time, always remaining very sticky for PLA provided the glass sheet stays at least 50°C. I use 228°C for the PLA filament, and 60°C for the printing bed. Heating at 60/70°C produces a huge adherence without needing any glue or whatever else - just the bare sanded glass sheet. And, once the printing bed becomes cold, every printed object, regardless of its surface size, spontaneously separates from the glass surface. No efforts or tools needed - just remove it like you would take an object off a shelf. I don't know if it's important, but I've been avoiding touching the surface with my fingers to prevent oil residue that could reduce adherence on the scratched glass. Anyway, there's no need to touch it because objects spontaneously separate from the printing bed once the glass surface becomes cold. A very interesting and positive side effect of this spontaneous separation is that there's no need to readjust the level of the printing bed once it's even - no possible disalignments at this step. I simply wanted to widely share this successful try, because I know many are in deep trouble with this adherence issue. To date, I haven't tried with any other kinds of filament using this printing bed. I'll update later. If you can give an update based on your own attempts with this solution or a similar one that may be helpful for others, please add it to the comments. The uploaded file comes from another project and is useless - just here to allow publication of the present information. I hope this tip will be as helpful (life-saver?) for you as it has been for me. Have a good day!