Organikum - 8-2-2004 at 04:40
I have some nice thin porcelain cups which call for being abused as cell dividers in a electrolytic setup but........
...they are glazed and so useless.
How to remove the fucking glaze without a sandblaster? Dont say "gringing stone" or "abrasive wheel" I already destroyed two cups
by trying this. As soon the wheel brakes through the glaze it breaks the cup as the porcelain below is to thin and much softer than the glaze.
I also would like to leave some glaze at the rim for preventing electrolyte getting sucked up there.
Molten NaOH seems to have no effects at all on the glaze - perhaps it is just a question of time?
Glass etching paste/sandblaster in a can ?
Hermes_Trismegistus - 8-2-2004 at 08:40
These products are pretty common here sold by Armor Etcha and Etchall
I'm sure they'd send them internationally but maybe there are similar companies in your neck of the woods.
http://www.etchworld.com/cgi-bin/cp-app.cgi
http://etchall.com/
if you wanted to do it manually and have alot of time on your hands try replacing your grinding wheel with a felt wheel and abrasive pastes/fine
pumice (rock shops)
Friedrich Wöhler - 8-2-2004 at 09:32
Hallo, k. und k. Hof-Chemiker Organikum, 
I wonder absolutely that molten NaOH (!) or boiling in conc. NaOH-solution shouldn't take effect...
Then try an H2F2-based problem-solution. There are (expensive) hobby sets available for glas corroding.
2th solution could be H2F2 or NH4HF2 from a lab-store.
In the EU is a product available what a solution of zinkhexafluorosilikate in water is. This I use as base for fluorine chemicals.I cannot remember
its name now. Here is a supplier with another name of this product:
http://www.bornit.de/pages/produkte/merkbl/pdf_dateien/sdb/a... (pdf-file in German language).
Or search in google for German trading-synonyme "fluat" or "mehrfach-fluat".
Greetings to Mozart's country!
Tried it again...
Organikum - 8-2-2004 at 20:04
with molten NaOH and - oha! - this attacks the glaze after some time!
And produces such wurface tensions that the cups burst apart and then broken, they dissolve slowly. The unglazed inside first is understood. 
Ok.
Now I retry the boiling hot NaOH saturated solution overnight and will probably go to hunt down some etching fluoride here tomorrow - probably I will
buy an sandblaster after I have seen the price.... LOL.....
No, probably I will go to a pottery and have the stuff made what will be much cheaper and better as fucking around with this by myself.
Hmmm. some electrolysis diaphragms and a set of retorts and tubes for the high-temperature and chlorine stuff.
Sounds good.
oh yes
axehandle - 12-2-2004 at 08:27
Why didn't you just buy new ones? They cost next to nothing?
Glaze Remover
Turel - 12-2-2004 at 09:30
http://www.google.com/search?hl=en&lr=&ie=UTF-8&...
Organikum - 12-2-2004 at 09:46
axehandle, make your choice:
- because I like to experiment
- because I am stupid
- because I am stupid AND like to experiment.
as you like it.
turel:
This is NOT the glaze I want to remove which Google shows up.
axehandle - 14-2-2004 at 01:22
I believe it's because you like to experiment.
You have already proved to me that you're absolutely NOT stupid.
Unless the glaze is made of porcelain enamel, I would suggest sand blasting OR placing the pieces in a kiln at a high temperature, where the glaze
hopefully would settle at the bottom.
Otherwise there's always the obvious way: chip of the glaze (carefully!) with the risk of destroying the ceramic substrate.
thefips - 6-3-2004 at 15:28
Just take HF and your problems should be solved...
Mumbles - 6-3-2004 at 17:10
I think the point was to remove the glaze without damaging the ceramic substrate. I think HF would damage the clay.