Borosilicate glass bed reversible?

I have a Taz5, and I bought the new dual v2 extruder. When I was testing and trying to adjust z height (and the z height of the second extruder to the first) I did a stupid and scratched my glass bed because my second extruder height was so far lower than the first. It actually looks like it etched the first layer of the print onto the glass. Fortunately I did not damage the extruder nor break the glass…

Now I have everything adjusted and level, and the prints are coming out great, except that I’m getting the etched impression on the bottom of my prints because the glass is scratched from that big fail.

I’d like to get a flat glass surface again. I’ve read that the glass can be sanded safely, but I think if I do that, I’ll need to sand down too much and end up with a less than perfectly flat glass surface.

So before I buy a new glass bed, I wanted to know: Can I just remove and reverse the glass? Is the back side also suitable for printing?

Chances are you just damaged the PEI surface covering your plate. This can be sanded using 1500+ grit sandpaper, and then wipe it down with a water and isopropyl alcohol solution to get the dust off. The glass plate has a silicon heater attached to the underside, and it will not be able to just be flipped.

If the PEI was severely gouged, it may need to be replaced. This can be a little tedious removing the adhesive, but it is much less expensive than buying a new bed assembly. You can find directions on the Mini (same process for TAZ but bigger) here: https://ohai.lulzbot.com/project/mini-replacing-pei/maintenance-repairs/

Hope this helps!

Oh, I had no idea that’s how the bed was put together, thanks! (Yes, I’m completely brand new to 3d printing) Now I see why they recommend sanding it down.

I’ll do the sanding it down first, as you recommend.

And thanks a lot for the link to the PEI replacement instructions, now I feel like a fool for thinking that the glass was dipped in some substance (liquid PEI? :slight_smile: ) and I could just flip it over :slight_smile:

There is such a thing as liquid PEI resen, so it’s not an unreasonable guess if you didn’t know better.

The school I’m working with had a problem with the first print they tried on their Mini. The put a few gouges in the PEI sheet, and about a 1/4" diameter hole melted all the way through the sheet and the nozzle was grinding around on the glass. Despite all that, the glass was fine. We just needed to replace the sheet (and get the tool head unclogged).

So if you’ve just got a minor gouge, I’m sure your glass is fine.