Author Topic: cleaning glass - revisited  (Read 4314 times)

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jimwig

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« Reply #20 on: May 19, 2003, 04:21:00 PM »
yep used DCM also but not much. Can't locate that 5 gallon carboy right now. heh heh

the nasty bases will probably etch the glass- don't you think. But a little etching wouldn't hurt. They are huge.

And just to be clear it's not "on anything" - its rather a mass sitting in the flask grinning at me. the glass itself is nice and clean - which is why i was searching for a "solvent" in order to dissolve (solvate ) the shit out the top.

Thanks for all the good help.

Atropos

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Base bath
« Reply #21 on: May 19, 2003, 11:05:00 PM »
Strong KOH dissolved in methanol... The classic base bath.

As for etching, take it out periodically, and check the junk you are tryig to remove.

Overnight almost always does the trick, without much etching, but watch any ground glass joints.

calcium

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Time to call in the professionals...
« Reply #22 on: May 20, 2003, 02:13:00 PM »
For lack of anything better to do, I called my friendly neighborhood scientific glassblower to get an opinion on this 5 liter flask. He said he would ash it (ramp up to annealling temp, then back down) which hopefully would reduce the polymer mass to removable ashes. He would follow with a hydroflouric acid wash and expect to return a clean flask for $30.00 USD. Don't try this at home, kids! I explained that the lump was an unknown polymer and he was confident that it would go away. The last resort would be scoring and removing the flask bottom followed by reblowing the flask bottom on a lathe. It's possible that my neighborhood supports better glassblowers than other neighborhoods. Just my two cents. That's what the man told me.

heavenadisaster

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can someone please explain the reaction ...
« Reply #23 on: May 20, 2003, 05:11:00 PM »
can someone please explain the reaction involved with the prahna (H2SO4  +  H2O2) and acetone? what doesn't react with it?

jimwig

  • Guest
that's what my glass man here said.
« Reply #24 on: May 21, 2003, 09:39:00 AM »
that's what my glass man here said.

take it up to about 600C - things carbonize and come off as CO2. then clean it up and presto brand new!!!

BUT i don't happen to have an oven that's big enough to do this.

My oven (kiln) is small - about 10x10x10 or so inches.
Will fire pottery (around 2300F - ?) but not large pottery.

Have tried the pirhana solutions but got scared and stopped after about 30 minutes. Don't ask why just felt it wasn't making any visual progress.(Probably the name)

 Should I just leave it in there for an extended period of time or possibly heat it up?

calcium

  • Guest
let your glassman do it then...
« Reply #25 on: May 21, 2003, 04:05:00 PM »
Your glass guy can do it in his annealling oven. Let him, if you really want to get that flask & mantle in working order.

jimwig

  • Guest
i do, i do!+
« Reply #26 on: May 22, 2003, 01:06:00 PM »
there's this logistics problem. I will say no more and thanks to all.