Shower Glass Print Bed

[Gary Schwartz]

I've tried mirror (shiny side up & shiny side down) with & without Kapton, & Home-brew ABS "paint", plain glass with & without Kapton & ABS paint, HBP alone, and not happy with any.

 

Lots of research led to the conclusion that the printed object needs a mechanical & chemical bond with the print bed.  Mechanical provided by non-smooth surface, allowing extruded plastic to get a "finger hold".  Some have recommended sandblasted glass or sandblasted mirror.  I had trouble finding a sandblaster that would produce a uniform "grippy" surface.  Also, inconsistency from one to another could result in inconsistent results.  So I gambled $13.00 on a piece of Matte Shower Glass.

 

I bought it from a bathroom specialty store that handles tile, glass, & all sorts of stuff.  The man who cut the piece for me made it a point to describe it as "Matte" glass.

 

My initial trials with ABS at 205 C hot end failed ... the print lifted at the ends.  At 230 C, & 110 C bed, and a light application of home-brew "ABS Paint", I couldn't be more pleased with the results.  As long as the bed is hot, I simply cannot remove the part.  I've tried using pliers, twisting, turning, rotating, tried wedging it off with a blunt-nosed X-Acto blade ... can't budge it.

 

After cooling, it comes off with finger & thumb.

 

Preparation for the next print involves only smearing a bit of ABS paint on the surface.

 

An example of its performance is printing the cubes (Thingiverse 23791).   These have a very small contact patch with the bed, and the printing process tries its best to break it loose.

 

I highly recommend Matte shower glass. 

[Ross Mosshart]

Have you tried BPT? I swear it's a magical experience...

[John Yang]

I also swear by blue painters tape (BPT). I use it on top of a 1/8th
inch thick aluminium plate on top of the hbp. The bed rises to about
95 and using brim on the latest slic3r helps keep the print solid to
the bed for abs. To remove I use a putty knife to slide under and pop
it off. I've ground a bevel on only one side of the putty knife so it
slides in easily. And if the tape rips, I peel off the strip and put
a new one on. And the aluminium plate means I don't worry about
cutting the traces when removing a print and I get an even heat spread
and added thermal mass once up to temp to keep things on the bed even
with light breezes. The cost is very low for the high performance you
can get.

[Gary Schwartz]

 

Yes, I've tried Blue Painters Tape on glass, but not on aluminum plate.  Not happy with it on glass.  If matte glass fails me, I'll give aluminum a try.  I can see where its thermal properties would be a plus.  If you want even better heat transfer, use fine wet/dry sandpaper to remove the lettering on the PCB.  This essentially eliminates the air between the PCB & the Al plate.

[Rayne Lang]

Hey, do you guys use BPT right on top of your heated build platform ever? I dont wanna do this and have my tape stick and never come off

On Tuesday, September 4, 2012 12:53:31 PM UTC-4, LJ wrote:

[Aaron Double]

One thing that I have found is it really matters what acetone and or rubbing alcohol you are using. Best to get it at a painting supply store and not a pharmacy. CVS 91% rubbing alcohol was a complete fail.

Aaron

[John Yang]

I have my hbp oriented so that the traces are up and next to the
aluminium plate. I've also applied heat transfer paste between the
plate and the hbp to make heat transfer better. I used the sliver
heat paste used for cpu heat sink attachment. In the orientation that
I have mine built, I would not take sandpaper to remove the
soldermask. Even when the traces are down, I think removing the
soldermask and/or silkscreen might be a bad idea since I'm not sure if
the large copper pour on the back side of the hbp is connected to
ground or not. The traces right next to the alu plate with the heat
transfer paste inbetween make for fast heating.

[Gary Schwartz]

Hmmmm.  Now on my list of experiments is: Aluminum plate scuffed up a bit with fine grit paper on random orbital sander, then a thin application of "ABS paint".

 

While on the subject of heat transfer (at least peripherally), I think we lose a significant amount of the heat produced by the PCB to the surroundings.  For example, the bottom of my plywood build platform is hot when my HBP is at 105.  This means that I'm losing heat there.  If the edges of our build surface are warm/hot, we're losing heat there as well.  Reducing these heat losses means faster warm-up, and more uniform temperature across the surface.  And, as mentioned in earlier post, sanding off the lettering on the HBP will speed up surface warming.

 

When my build surface is REPORTED as 105 C, that's what the thermister reads.  My IR temp gage says 100C at center of build surface, and it falls off to ~ 90C at edges.

      Gary
Make Better Things
Make Things Better

[Gary Schwartz]

I must have tried it, but don't remember the results.  Must not have been good since I've gone on to other methods.

      Gary
Make Better Things
Make Things Better

 

 

 

 

[John Yang]

I insulated the bottom of the hbp with some cardboard covered in metal
vent foil tape. The shiny metal should help rediate back a little
heat, and the air pockets of the carboard give a decent insulation vs
direct physical contact to the plywood. you could use any insulation
below and help the heat go only where you want it. I've got some
foamcore set aside that I was going to try the next time I have to
tear down the bed for maintenance.

[Gary Schwartz]

John,

 

I agree that no sanding should be done with plate oriented as your's is.

 

I also stand by my recommendation to sand it if lettering is on top side.  I've had no problem with my sanded HBP, and I was pretty aggressive.  I see some copper at the edges.

I've done a lot of digging on heat transfer, and become convinced that heat-conducting paste is effective because it displaces the air between the surfaces.  The best heat transfer occurs when the two surfaces are in intimate contact.  When I tilt my glass up ~ 30 degrees, he HBP follows as though it were glued, then will drop off.

      Gary
Make Better Things
Make Things Better

 

 

 

 

[Gary Schwartz]

Foamcore: good thought.  Will it withstand 110C?

I'm considering 1/2" blue rigid wall insulation.

[David Buggs]

Get a tube of thermal paste, the kind used for mating CPUs to fans.  That would eliminate any pockets between the HBT and the AL, it is a mess on fingers but wipes off cleanly if you change your mind.

Buggs

[sto...@gmail.com]

So sad you've got the issues. Just about anything works well. Alum., glass, copper. I understand ceramic tile, steel.... I've used OEM HBP, OEM belt, painters (bpt) tape on copper, bpt on glass, kapton on belt and copper. Temp is important. And what is often not correctly done is to level the bed and to adjust the height. I use a sheet of printer paper or a stcking under the print head at the point it lightly drags as I pull it out then set the Zheight. I also use a dial gauge for leveling the bed to roughly .05mm or better across the entire surface. I've not used the ABS slurry....

[Nolan Poe]

Sounds really expensive. I would personally try to remove the lettering before messing with thermal paste. That stuff is supposed to help with surface imperfections, not physical gaps.

[NCBob]

I've tried some of the other things mentioned here, and my latest experiment has been with laser etching a piece of glass. I did octagonal patterns on it, and the first quick test we did worked really well.

I just need to spend some more time testing it, and getting a piece of glass for my mendelmax and etching it and seeing how it does.

[Gary Schwartz]

Matte shower glass is already etched ... and available.

      Gary
Make Better Things
Make Things Better

 

 

 

 

[NCBob]

*shrug* I like that I can try different patterns and see how it effects the adhesion, and I don't want to use any slurry at all.  With the matte shower glass you still have to use slurry.

[Gary Schwartz]

Why is slurry objectionable?

[Bill Culverhouse]

On Thu, Sep 6, 2012 at 12:16 PM, Gary Schwartz <gschw...@gmail.com> wrote:

Why is slurry objectionable?

Heatbed boiling off acetone fumes inducing feverish nightmarish hallucinations?
(Kidding) :-)

-b 

[NCBob]

messy, pain in the butt to always need it to print. I'd much prefer to just start a print without having to clean the slurry off and apply a new coat.

[Gary Schwartz]

 

I've found no need to clean it off.  Merely a casual wiping of the build surface that was affected by previous print does the job.  About 30 seconds involved.

Never have to be concerned about damaging or replacing tape.  Bottom surface of prints is mirror-like.

[Gary Schwartz]

Could it also explain my intense headaches, black-outs, loss of memory, seizures, loss of appetite, and no longer caring for beer?

      Gary
Make Better Things
Make Things Better

 

 

 

 

[NCBob]

I want to be able to print just like we do with PLA and bpt.

I think that the glass will work and the etching let's me determine the best compromise between adhesion and easy removal.

Ymmv with the slurry depending on a lot of factors, with the glass its just the etch pattern and depth.

[Jay Couture]

Interesting how the matte glass gives a mirror finish. Do you have any photos for the quality you are seeing that you can share?

[Gary Schwartz]

Good question Jay.

While attempting to get a good photo of prints with mirror-like bottoms, it occurred to me that they were printed on a mirror with ABS slurry.

My prints on matte glass with ABS slurry have a smooth, but not reflective, bottom surface.  No waffle pattern or tape-gap ridges.  I get a very good reading of the quality of my first layer.

 

Sorry about my error, and glad you caught it.  If we're to progress, we need factual information.

 

As said in my previous life: "In God we trust, all others bring data." (or photos)

 

      Gary
Make Better Things
Make Things Better

 

 

 

 

[jay.c...@gmail.com]

Don't misunderstand, I really do want to see the quality you see and was not being facetious.

Sent on the Sprint® Now Network from my BlackBerry®

---

From: Gary Schwartz <gschw...@gmail.com>

Sender: make...@googlegroups.com

Date: Sat, 8 Sep 2012 10:28:48 -0400

To: <make...@googlegroups.com>

ReplyTo: make...@googlegroups.com

Subject: Re: [MakerGear] Shower Glass Print Bed

[Gary Schwartz]

Jay,

 

No misunderstanding.

Your request is valid, and one that should be asked and answered more often.

I've taken several photos of mirror-like bottoms, and will take some of matte glass print bottoms.  If they look representative in Photoshop, I'll post them.  If not, I'll take more.

 

Delay due to designing a project in Autodesk Inventor, which I'm learning as I go.