Ive heard about using paper, hairspray, painters tape, wax-paper or just printing straight to the bed. What is the consesus on the forum about the glass bed? Should I use it or not? If not, whats the BEST alternative?
I have used glass with hair spray and hair spray on the bed itself
The glass works good but the clips to hold it on (large paper clips) get in the way.
Please tell me if TL/DR in your response.
A glass bed will do well for dry printing of both PLA and ABS. Unless your printer is in the oven, the stock power supply WILL NOT heat the glass enough to properly print ABS. If you need some help with adhesion, try Elmer’s Purple Washable Glue Stick. Apply the purple stick right after you’ve started warming the bed. If you go over about 40*C, the glue will start getting messy. Just apply a thin layer… and get yourself a 4" blade scraper from the paint section of your local hardware store. That Elmer really knows how to make glue. Most of my prints are made with clean, dry glass, rubbed with 70% denatured alcohol right after I start the warm-up cycle.
If you’re able to attach a 24-27V power supply (150W) to the stock bed, you’ll be able to get enough heat for printing ABS. I’m able to manage a temperature delta of 102C with a sheet of 4mm cork, topped by the FR4 printed circuit board, all under a Velleman branded sheet of tempered glass, fed with a 27V power supply. The warm-up cycle is really short with 27V (about 3:30 minutes to go from 15-60C). Keep the bed well leveled (springs REALLY help) and ABS will stick to 100*C glass. Large parts may still need the glue. Things like Nylon, Polycarbonate, and Acetal are going to need more than just the glass bed top.
Some folks report success with Garolite, which I believe is the brand name for older printed circuit board material (G10). Printing directly to Polycarbonate apparently can help some materials (ABS?). Obviously, you won’t want to print similar materials on top of each other. Not only that, pay close attention to T-sub-g (Glass transition temperature) for the material you use as a print surface. FR4 starts transitioning out of its glass phase at 140C, which is why a stock heated bed shouldn’t be used above that temperature. Essentially, an amorphous material has a large range of fluidity that has a lower limit at the glass transition temperature. If the temperature of your heated bed is set just above the glass transition, then the bottom surface of the printed object is highly viscous, yet not quite solid. In other words, we’re making sure that the bottom of the part remains tacky. ABS has a glass transition around 105C. PLA turns to glass at around 50*C.
Tempered glass has a very high glass transition temperature (Wikipedia puts it at 564C), which makes it an excellent choice for a print surface. While Borosilicate glass is much more amenable to temperature changes, its much lower glass transition temperature of 288C makes it a borderline candidate for things like Polycarbonate that require an extrusion temperature of nearly 300*C for proper flow. I’ve considered the addition of an Aluminum sheet under the glass to ensure complete heat distribution, while maintaining the thermal mass of a glass top, and avoiding thermal conductivity of an Aluminum-to-Air junction. Either that, or I’ll make a separate thermistor board with four 100Ks in series parallel. (Yes, I notice the thermal impact of printing over the single 100K thermistor on the FR4.)
Update: I made a mistake on the T-sub-g value for ABS.
The glass is very flat compared to the bed alone, which really helps for good adhesion of the first layer. It is easy to keep clean by scraping with a razor blade.
The clips I printed out of PLA have loosened from the heat of the bed. When I print new ones I will use ABS. There are improved designs available… thingiverse.com/thing:673368 looks good.
Bang for the buck, the glass bed is the best upgrade you can make to your printer, IMO.
My printer came equipped with a ‘Buildtak’ Surface on the standard bed. (Google it)
I never had any object come loose during printing. Its perfect in my opinion, never had to try sprays or glues or whatever… My PLA objects always stick perfectly.
When printing on a glass plate, the surface that printed first on the plate will be perfectly smooth, this might be handy if you want a shining flat finish to your object on 1 surface.
The Buildtak leaves a somewhat dull surface, but since the rest of the object is never perfectly smooth due to the printing in layers, I don’t care.
I glued a glassplate to the stock PCB bed, to make it much more flat.
To print PLA I use some self-adhesive plastic window foil on it, at a temperature of 65 degrees.
Printing PLA directly on the glass never succeeded.
To print ABS I heat up the glass (without foil) to 98 degrees (the maximum with my 24V power supply)