PETG removing Black Diamond coating - What is the risk?

compman2

I am a new user with a JGAurora A5.  Thanks to the wiki I have been having a great printing experience.  I immediately flashed the community firmware and screen firmware when setting up.  I have done a mesh bed leveling per DaHai.  I have had to tweak temperature settings for Bed and Hot End for the provided filament, but have been successfully printing for a couple of weeks.  Watching the printer work is mesmorizing.

I have a new roll of PETG from MatterHackers that I want to start using.  I have heard of cases where the PETG prints pull up the Black Diamond coating from the heated bed.  My question is how great of a risk is it to print directly to the bed?  There is a Youtube video from DIY3DTECH showing the PETG prints coming off the bed with no problem.  Others recommend spraying the bed with hair spray before printing.  If this is a defect and effects only a few printers I would take the risk and print a small print near the corner of my bed and see what happens.  If it seems to be very prevalent then I will take precautions.  I have a version 7 machine with the notched corners on the build plate and attachment clips.  I want to avoid painters tape because it would most likely require a new mesh bed leveling with the tape in place. 

I would love some feedback on this.

Samuel Pinches

I think the risk is very high, especially for prints with large flat areas on the build plate. I've seen it happen to several users, and it has even happened to me before on plain glass with previous printers! Taking off the plate and spraying with hairspray (not over the printer...) is probably a good measure to help weaken the direct adhesion, but even that may not be enough for large flat prints, so be careful of those in particular. When removing PETG prints, avoid pulling straight up.

compman2

Would a better solution be to get another piece of glass cut and apply buildtak or PEI surface.  Do you know if the version 8 A5 uses adhesive to attach the glass to the heated bed or is it held on with only the 4 clips?

Samuel Pinches

You could definitely try that... buildtak might be better as PETG sticks very very very well to PEI. I don't know sorry... and even if I did know, it still could be different on your machine.

coffeeroast

I always spray a mixture of alcohol and water on the component and the bed after the print is done. Then, after a while, the petg gets off the bed alone.It seems that the mixture migrates under the component and so the PETG solves without problems.
For me there are no problems with the coating.

compman2

Coffeeroast what mixture of alcohol and water are you using?  I tried cleaning my bed with 90% rubbing alcohol and it seemed to eat into the surface a bit.  The bed got slightly tacky for a bit and it left a slight haze.  Since that I have avoided alcohol on the bed only windex.  I read somewhere to only use ethanol on the bed. 

coffeeroast

I use finished glass cleaner, with much less alcohol in the water. With methylated spirits.

https://www.frosch.de/Products/Cleaning/Glass-Cleaner/Bio-Spirit-Glass-Cleaner.

No problems with that.

compman2

So finally started printing PETG.  I am still in the figuring out process but getting prints.  I am using Aquanet Professional Hold Unsented hair spray as a coating on the bed before printing.  I haven't had any removal issues even with parts with good sized build plate contact.  I will say when the parts are removed you can see where the hairspray has been removed on the bed.