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Tried borosilicate glass

Posted: Wed Jul 01, 2015 9:43 pm
by Robin
Or Pyrex as we call it in the UK.

First the aluminium bed was not flat enough, one of the 2 holding down screws protruded a bit. I put a washer on and it would not screw in, turned out the thread was oversize and the screw undersize. I countersunk the bed and bolted it from above. Fixed.

The perfboard clips were not big enough, luckily the glass came with 2 bigger clips and a bunch of prints that I could not be bothered with.

I tried printing on it, no adhesion at all although the bottom of the print came out wonderfully flat.

Added a wash of ABS in acetone. This sort of worked but it was a bit unreliable and when I removed the finished part it was obviously a blooming miracle that it had worked. Zero effort required.

Then I added Kaptan tape and a wash of ABS in acetone and everything was fine.

So what was the advantage of using glass over using perf board?

Not a lot if you print tall thin stuff like me, but there are some...

If you are doing repeat prints you can apply the Kaptan so that initial, get the nozzle going, squirt misses it. There is so little adhesion you can flick it off with one finger.

The print head would normally extrude the tape down into the perf board and give you a dimpled surface. None of that.

The tape seems less willing to bubble when you remove the part. Possibly because the air cannot get under it so easily. It will bubble if you are rough, don't be rough.

Maybe it will be wonderful when I do wider prints. I did buy a thermally conductive adhesive sheet to put it down but that does not appear necessary.


Re: Tried borosilicate glass

Posted: Wed Jul 01, 2015 10:09 pm
by mr6k
I'm with you.
I have an original UP Plus with aluminum base plate. I had, after experimenting with a multitude of means to get the ABS to hold to the base, firmly come down on the side of Kapton tape on the solid base with a very thin wash of ABS dissolved in MEK, similar to Acetone. Having of course first removed the release agent that is on the Kapton tape. Just wash off with Acetone/MEK. I can get several dozen medium sized prints before needing to lay fresh kapton tape.

In terms of the acetone/MEK wash, I have a slab of ABS which was made from old abs duff prints dissolved in MEK, then the solution poured into an old tupperware box and allowed to harden. Slab easily removed from tupperware. I then soak a tissue in MEK, wipe it across the ABS slab a couple of times and then wipe the tissue across the Kapton, works each and every time.



Re: Tried borosilicate glass

Posted: Sat Jul 04, 2015 1:19 am
by FallGuy

I actually just use the glass and give it some swipes with a children's Elmers glue stick.It has a twist knob to push it out of the tube and I apply two even layers; first, one left to right for full coverage, then a second even coat front to back. The glue starts out purple, but as it dries it turns clear/white. I still pre-heat the aluminum bed to about 95 or so before I start to print, but I think I have heard some people have disconnected their bed heaters when using glass/glue. I have to use a small spatula to lift the prints off the adhesion is son good. In fact. because the adhesion was so good, I actually had a glass plate crack on me. I was printing what was for me a large part (not as large as what others have done though!) and so I prepared the glass as i described above and started printing. About 3/4 through the printing, i thought I heard something pop but didn't really see anything wrong, it wasn't till later did I realize the glass had cracked.

Because i had never really done "large" parts I had never needed a heated chamber to prevent warping of parts as they cool while printing. But in this piece the stress of it cooling and warping was too much for the glass to take since the print could not "pop" free from the glass and it broke. Looking at your picture it looks like your glass is thicker than the ones I got from Octave so Your will probably hold up really well.

Good Luck!

Re: Tried borosilicate glass

Posted: Sat Jul 04, 2015 7:23 am
by DrewPetitclerc
I use glass and glue stick all the time on all the machines at my work (4) and home (2), always get the part off before it cools completely or it will most likely break the glass, I always set the build plate to keep heating for 60 minutes after printing to give time to get back to the machine to remove the part.
Also this technique will ONLY WORK if your build plate is trammeled (some say level) to the nozzle to a very tight tolerance.

Re: Tried borosilicate glass

Posted: Mon Jul 06, 2015 8:44 am
by Robin
So which Elmers glue stick do I buy? If I type it in to e-bay it is all "from the United States", in the UK Pritt seem to have the market pretty well sewn up. You say "purple", there is washable purple school disappearing glue, is that the one?

Re: Tried borosilicate glass

Posted: Mon Jul 06, 2015 4:44 pm
by FallGuy

That sounds like the one. Here is a link to the one i use: ... uct_488126

It goes on purple, and then slowly fades to clear as it dries/warms up. Then after I have removed my part from the glass, I wash the glass with warm water and it turns purple again as it gets wet.

Hope this helps.

Re: Tried borosilicate glass

Posted: Wed Jul 08, 2015 10:01 am
by Robin
I just bought a 2 pack for £2.54 with free shipping. I think this might take a while :mrgreen:

Re: Tried borosilicate glass

Posted: Tue Jul 14, 2015 9:19 am
by Robin
Just got an email to say my glue has been dispatched.

On reflection I am guessing the extra weight added to the platform was the cause of my recent print problems which I put in a separate thread.

It seems the aging belt clamp next to the heater simply could not take the strain of accelerating an extra 128 grams :mrgreen:

Re: Tried borosilicate glass

Posted: Sat Jul 25, 2015 4:04 pm
by roller
I print straight on to glass. No Elmers and no ABS paint.

What I have found is not all glass is created equal and my first source of Borosilicate glass worked perfectly. I've since bought sheets that do not work and need Elmers. I don't know why some glass works and some doesn't but there is clearly some difference in the surface finish of some glass that makes it grippier. I wish I could identify this before buying but I don't know what it is yet. The best thing about the good glass is it grips well, you don't get variations in the surface finish due to variation in adhesives and when the glass cools the print simply pops off on its own.