jimwig (Hive Bee)
05-12-03 12:26
No 432833
      cleaning glass - revisited  Bookmark   

okay - i acquired recently two 5 litre four neck RB's.
both filled with some sort of solidified substance - probably a polymer (plastic) - knowing generally the nature of the source.

I have tried the following:
and a few I don't recall.

Still the solid remains. The glass is fairly clean just a loose globulous solid refusing to dissolve and just resilient enough to resist any cutting/grinding action to reduce the size.

Any ideas?
05-12-03 12:40
No 432837
      gunk remover  Bookmark   

has swiy tried boiling muriatic?
(Hive Bee)
05-12-03 12:42
No 432838
      what were u cooking previously?  Bookmark   

I remember reading in one of the mdma writeups, in one of the steps the goo comes out cleaning with methanol. 
otherwise put ipa in to the glass, boil the crap out of it with a fan blowing on top.

Just work it baby!
(Hive Addict)
05-12-03 14:59
No 432854
      round and round...  Bookmark   

A liter acetone and a pound table salt. In the flask. Stopper well fixed. Packed in a old blanket and up in the washing machine - with or without water doesn´t matter, just  fill with old blankets/socks whatever so it wont break and it should sit NOT in the center of the axis. Use the part of the program only where the washing powder gets washed out at end ("spülen").....left around. right around....
Hours later:
Praising wonders of civilisation or taking a more aggressive abrasive and try again. MEK might be worth a try also.


(Hive Bee)
05-14-03 18:18
No 433233
      round etc sounds good but---  Bookmark   

putitng a three hundred dollar item in a washing machine - gee I don't think so but thanks anyway.

hot muriatic - or anything above room temp has not been tried.

genrally this mess is definantly non-polar.

since I was given these along with the GlasCol to fit -I really don't want to lose them. Just mantel decorations they will become if uncleanable.

rudebwoy- the contents were well fixiated upon my acquisition and not of my doing - cooking or otherwise.
(Hive Addict)
05-15-03 00:15
No 433271
      a question of proper fixing  Bookmark   

putting a three hundred dollar item in a washing machine - gee I don't think so

It is a question to pack and fix the items properly - if this is done there is a minimal probability left that they will get damaged. Much less as trying to solve the problem on other ways with the included handling by the known prior point of failure - the human.
If you have an big enough shaker you can use this, but truely: The washing machine is superior. laugh

But it´s on you, as it is your glassware and I won´t try to talk you into something. smile

05-15-03 16:14
No 433408
      if you have a well source for nitroethane try...  Bookmark   

if you have a well source for nitroethane try that it dissolved the most plastics i know
(Hive Bee)
05-15-03 23:26
No 433488
      I have never done this. Its just an idea.  Bookmark   

I have never done this. Its just an idea.

What about adding an excess amount of Teflon to the flask, heating it up to melt and then see if it bonds with and removes the residue?

when we forget to pray for the angels, the angels forget to pray for us!
(Hive Addict)
05-16-03 07:12
No 433542
      even a only slight cold amount  Bookmark   

of telefon would work better IMHO.

TEFLON? PTFE? Inert, not adhesive to anything.
But the idea is new. And untried I bet. - who is first at the patentoffice?
(Hive Bee)
05-16-03 09:52
No 433568
      use a toothbrush and some elbow grease :)...  Bookmark   

use a toothbrush and some elbow grease :)

(Hive Bee)
05-16-03 13:47
No 433607
      the adventure continues  Bookmark   

--all boiling - nothing dissolved

I WISH I had nitroethane. along with the rest of the bees here.

It is the inside of the flasks that contains large clumps of polymers. A toothbrush and trained gerble, eh?

The precious little tetraflorethylene that lives with me will continue to do so.

But thanks for the thoughts.....
05-16-03 16:53
No 433628
      Pirahna Solution?  Bookmark   

This is probably too dangerous a solution because this stuff is explosive in the presence of acetone, but for the sake of adding an alternative I present some snippetts about Pirahna Solution from an online forum that I've had around, maybee found through the Hive or Rhodium...
"> >hi netters:
> >
> >Where would I find the recipe for making chromic acid
> >solution for cleaning glassware? 
> A nice alternative is conc H2SO4 + 30% H2O2 (in approx.  3:1 to 4:1
> proportion respectively). It does a great job on those glass frit
> crucible funnels! Be careful though, it spits hot H2SO4, so be sure to
> keep it covered.

     That's going from bad (carcinogen and environmental no-no) to
worse.  Some of the worst lab accidents around have been caused by
using this so-called "piranha solution".  Yes, it cleans glassware
really well, but it also reacts violently with many chemical residues.
If you do you use this concoction only generate small amounts at a time
and KEEP IT AWAY FROM ORGANIC SOLVENTS.  Do not make the mistake of
mixing this stuff with acetone (as you might accidentally do cleaning
frits).  Treat it with a VERY healthy respect -- cleanup time is when
we tend not to pay attention to things and is therefore when accidents
are most likely to occur.

     "Safer" alternatives are KOH/ethanol as suggested already and
NoChromix (a packet you add to a bottle of sulfuric acid).  Actually,
soap and water removes most stuff.

     I did have a former colleague who regularly used piranha solution
with an added dash of Clorox (5% sodium hypochlorite, i.e. bleach).  I
have to admit that it did clean well.  Plus it gave a really neat
greenish cloud of Cl2 to admire and breathe...

(Hive Bee)
05-16-03 20:02
No 433644
      peroxysulphuric  Bookmark   

Hit it with a strong caustic solution and then after a rinse with peroxysulphuric as calcium stated above. Pour a bit of 95+% sulphuric into the flask and then add a few dollops of 35% peroxide, it should get very hot and burn the polymer out, turning it to fluffy carbon.

I wouldn't say it makes an explosive mixture with acetone as it doesn't have the time to react into acetone peroxide but the heat will boil it instantly spraying solvent/acid out of the flask. Rinse well before doing this but it is perfectly safe as long as you let it react in a sink with a loose cover on it.
05-17-03 06:40
No 433708
      pirahna solution + acetone  Bookmark   

Here's the Cornell University horror story about mixing these two, it sounds impressive... I appologize if this has been posted at the Hive before...

"Date: 9 Apr 1997 14:00:06 GMT

In article <334A4298.C1C@lanl.gov>
"Rebecca M. Chamberlin" <rlmiller@lanl.gov> writes:


> However, using it in an R&D lab is asking for trouble.  A classic lab
> accident with piranha solution occurred at Cornell in 1986 or so.  The
> grad students in one lab used to rotate responsibility for cleaning all
> of their glass frits by running piranha solution thru them (using "house
> vacuum") into a filter flask.  One student made the mistake of leaving a
> trace of acetone in the flask.  When the piranha solution hit the
> acetone, it went BLAMMO and a million pieces of glass embedded
> themselves into her face.  Thank heavens she was wearing her safety
> glasses or she would most likely be blind now:  the lenses in her safety
> glasses were shattered but still intact in the frames.  The chemistry
> department took a photo of the glasses and used it in their "Are you
> wearing your safety glasses?" poster for years afterward.  Not
> surprisingly, the student decided to leave chemistry after her
> hospitalization. 

As it appears that Becky, I and others have not quite gotten the point
across, let me drive it home one more time.  While you can usually tell
a conversation among chemists has gotten lame when they start swapping
lab accident stories, it is important that you **understand** that the
risk of using this solution is nowhere near the reward.

What Becky is writing about is 100% true.  I saw it.  It happened.  It
could just as easily happen to you.  Read this and then ask whether a
clean frit is worth this.

I was the first one to get to scene of the above incident.  We heard a
sound like an M-80 (about a quarter stick of dynamite) from two labs
away.  We got there within about 5 seconds to find her on the floor
halfway across the room surrounded by a large pool of blood.  The
filter flask that she was using turned to dust; we never found a
fragment larger than about 2 mm even though it had been wrapped in
heavy black electrical tape.  The metal 3 prong clamp that held the
flask sheared off at the point where it was clamped to the latticework
in the hood.  A row of glass cabinets along one wall were peppered with
holes from the shrapnel.  The lab had one of those 100 mm diameter
glass drainpipes running vertically on the wall opposite the hood
(about 8-10 m away) -- the pipe cracked in the middle ...we believe
that it wasn't from shrapnel, but from the compression wave of the

The student was wearing rubber gloves, a thick sweater, a lab coat, an
apron and safety glasses at the time of the explosion.  The hood was
down part way and saved her from catching most of it in the face.  The
arm holding the frit caught most of the damage -- the glove was
completely flayed and her arm had several hundred small bits of glass
in it as well as several fairly large lacerations.  She had a wound
about 20 mm in diameter just next to her jugular vein.  At least one
piece of glass went through her cheek. She (and everything else) was
also covered with hydrogen peroxide and sulfuric acid; something that
we didn't realize until much later because we had no way of knowing
what had happened.  I think the bleeding stopped more because she went
into shock than from the pressure were were applying in two different

She spent the next six hours having tiny bits of glass picked out of
her arm, neck and face.  I'm told that you continue to have those work
their way out of your skin for the next several weeks after such an
incident -- that you sweep your good hand across the arm and cut
yourself on the glass sticking out of your own skin.  This student had
some nerve/tendon damage and lost a bit of the motion in one or two of
her fingers; I can't recall if she had any hearing loss or not.  All
things considered, she got off pretty lucky.  And yes, she did leave
the program a short time after.

Now consider this:  10 minutes later and the rest of my research group
would have left for dinner.  She was working ALONE in her laboratory,
"just cleaning up".  Maybe she could have gotten to the phone on her
own...when I got there she was trying to get up, but not very
successfully.  Ever try to stand up in a pool of your own blood and
sulfuric acid on a linoleum floor while dazed and injured?  Me neither,
but it certainly didn't look very easy.  Think about that the next time
you are working a late night alone.

The odd thing here is that if she hadn't been working alone there would
have been many other injuries in that laboratory.  We found one large
chunk of glass imbedded in a bookcase over someone's desk.  If the
owner of the desk had been there he would have caught this fragment
with the back of his neck.  I can not stress enough how **stupid** it
is to put a desk or glovebox opposite a fume hood (or having a desk in
a lab, but that's not always avoidable).  Look around your lab and see
if you have that configuration...it's scary.  And the next time you see
someone without their safety glasses on, help them find a pair or make
them leave.  It is one thing to be an innocent bystander, it is another
to be a stupid bystander.

BTW, the shattered safety glasses Becky is referring to were from a
separate accident at Cornell involving a vacuum line explosion, but
that's another story and I only know it secondhand.  Part of their
rather effective campaign to make you think about safety.

Let me just end with the question I posed at the beginning:  Were a
batch of clean frits really worth all this?

(Hive Bee)
05-17-03 10:02
No 433731
      tough cookie  Bookmark   

tried this last night

concentrated H2so4 into flask
30% H2o2 into the flask

the flask got HOT
let it stay in the flask with occasional swirling
about ten to fifteen minutes

result: nothing dissolved

(Hive Addict)
05-17-03 10:59
No 433738
      akkk Peroxides!  Bookmark   

Ether, tetrahydrofuran, hexamine, acetone the list of High explosive peroxide initiators is endless.. i wouldn't do this for anything!

Infinite Radiant Light - THKRA
05-17-03 11:03
No 433739
      worth a shot  Bookmark   

an old buddy of mine--who just happened to work for a majot oil corp AND whose area of specialty research was polymers--recomended using Methylene Chloride. Since we can't run any spec scans or x-ray specs he said "that's a bad mother pucker which should rip the ship out of the nastards"

----just truckin
(arrogant bee of the day)
05-18-03 00:13
No 433865
      Re: I have tried the following: acetone nitric  Bookmark   

I have tried the following:

05-18-03 18:52
      tried this last night concentrated H2so4 into...
(Rated as: insignificant)
(Synaptic Self-Mutilator)
05-19-03 12:50
No 434176
      Concentrated base or burn them off  Bookmark   

I'd recommend a highly concentrated solution of NaOH or KOH, becareful not to add it around the joints. Bring it to high temps with a bit of stirring, or let it sit at room temps for a few days.

If the stuff doesn't come off then, then FORGET IT. For all intents and purposes, it's not going to come off (because that stuff will normally take the glass off...)... if you treat it like so, you could likely use the flasks as is without further cleaning.

Or, if you're still not happy, you could take it to someone who works with glass and put it in a high-temp oven. Everything will just be burned off or with inorganics infused into the glass.
(Hive Bee)
05-19-03 16:21
No 434221
      more  Bookmark   

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.
(Stranger / Eraser)
05-19-03 23:05
No 434275
      Base bath  Bookmark   

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.
(Hive Bee)
05-20-03 14:13
No 434395
      Time to call in the professionals...  Bookmark   

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.
(Hive Bee)
05-20-03 17:11
No 434413
      can someone please explain the reaction ...  Bookmark   

can someone please explain the reaction involved with the prahna (H2SO4  +  H2O2) and acetone? what doesn't react with it?
(Hive Bee)
05-21-03 09:39
No 434577
      that's what my glass man here said.  Bookmark   

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?
(Hive Bee)
05-21-03 16:05
No 434629
      let your glassman do it then...  Bookmark   

Your glass guy can do it in his annealling oven. Let him, if you really want to get that flask & mantle in working order.
(Hive Bee)
05-22-03 13:06
No 434787
      i do, i do!+  Bookmark   

there's this logistics problem. I will say no more and thanks to all.