Armed Polite Society
Main Forums => The Roundtable => Topic started by: zxcvbob on September 20, 2020, 11:34:44 PM
-
I bought some sulfuric acid drain cleaner to clean an Erlenmeyer flask that had crud stuck to the bottom that I couldn't get off with anything else. It did a pretty poor job at first (but it did kinda work), but then I heated it and it worked great. That was a couple of weeks ago.
A plastic carboy that I used to ferment some beer had a white streak on the outside that I couldn't wash off. I thought it was yeast from when the beer foamed out the top of the air lock, but I couldn't figure out why it was stuck so tight. Tonight I decided to use the ol' H2SO4 on it. The carboy is PET plastic, and that's acid resistant, right? I used a Q-tip to apply the acid (the acid ate the cotton off the end right away but the stick part still worked) and it seemed to be working but awfully slowly. I thought that was just cuz the acid was cold, but I couldn't use hot acid for this. After it looked like it was all gone I washed the carboy with some water, and the whole area turned white. I scrubbed it a bit and a lot of the white came off but it still looks like *expletive deleted*it. Since it's on the outside and doesn't go very deep, it's still usable it just looks awful. What happened? (rhetorical) PET doesn't contain any oxygen in the molecule for the acid to attack (along with 2 hydrogens), does it? I looked it up.
(https://upload.wikimedia.org/wikipedia/commons/thumb/e/ee/Polyethyleneterephthalate.svg/300px-Polyethyleneterephthalate.svg.png)
D'oh! :facepalm:
I thought it was just huge chains of carbon and hydrogen, but that's polyethene (and polypropylene).
PS, the original streak was probably from sulfuric acid when I opened the bottle and spilled a drop w/o realizing it. I opened it right there by where the fermenter was sitting.
PPS, sulfuric acid will etch the 420j2 stainless steel tip of your Buck knife when you use it to cut the plastic seal on the bottle.
-
Oops.
-
Ha, well now you know, and we know, so thanks for that. =)
Piranha solution (https://en.wikipedia.org/wiki/Piranha_solution) is excellent for cleaning most organic crap off glassware, although finding hydrogen peroxide in a useful concentration can be a chore.
-
Ha, well now you know, and we know, so thanks for that. =)
Piranha solution (https://en.wikipedia.org/wiki/Piranha_solution) is excellent for cleaning most organic crap off glassware, although finding hydrogen peroxide in a useful concentration can be a chore.
I'm aware of piranha solution, but can't find strong H2O2. But 93% sulfuric acid works just fine when it's hot. I think it becomes an oxidizer, plus pulling the water out of anything that has both hydrogen and oxygen in it. Just let it cool completely before you dump it in the toilet ;/
-
^And keep a bucket of water handy fir a quick-follow-up flush.
We used to use "chromic" acid, suphuric and potassium permanganate (an oxidizer, like H2O2) to clean burned-on organic crud. I don't remember where the chrome came from, though. I always thought it was a misnomer or they were referring to something else by accident.
What I reallly wanted to add is that a way to scrub the insides of various glassware was to slosh some kitty litter around in it.
Yes, it would seem that con sulphuric will steal H and O in the form of water from just about anything. It is nasty stuff, as if I were telling you anything new.
Keep that sodium bicarbonate handy,
-
Ha, well now you know, and we know, so thanks for that. =)
Piranha solution (https://en.wikipedia.org/wiki/Piranha_solution) is excellent for cleaning most organic crap off glassware, although finding hydrogen peroxide in a useful concentration can be a chore.
Walmart.
https://www.walmart.com/ip/H2O2-Liquid-Oxygen-34-Gallon/245174221
-
Walmart.
https://www.walmart.com/ip/H2O2-Liquid-Oxygen-34-Gallon/245174221
Wow. I had no idea they sold stuff like that. And the price doesn't look bad. (Liquid Wart Removers??)
Yes, chromic acid is a real thing, and it's another strong oxidizer. Chromium VI is nasty stuff. Not sure if there's a good way to reduce it to Chromium III for disposal.
-
A big vat of Piranha solution is my fantasy when it's time to clean up leaves in fall. :cool:
-
I remember from chemistry class using a solution of potassium dichromate and sulfuric acid to clean lab glassware. Worked OK.
As far as using it to clean plastic, if you do a little google searching you can find numerous chemical resistance charts which will help you determine whether or not a particular acid, solvent, or oil is compatible with a particular plastic.
Example:
(https://external-content.duckduckgo.com/iu/?u=https%3A%2F%2Ftse1.mm.bing.net%2Fth%3Fid%3DOIP.fv_zuVY4NXBFLVkhVwqC4wHaJX%26pid%3DApi&f=1)
-
A big vat of Piranha solution is my fantasy when it's time to clean up leaves in fall. :cool:
Total oxidation for everything! :lol:
-
Wow. I had no idea they sold stuff like that. And the price doesn't look bad. (Liquid Wart Removers??)
Yes, chromic acid is a real thing, and it's another strong oxidizer. Chromium VI is nasty stuff. Not sure if there's a good way to reduce it to Chromium III for disposal.
I used chromic acid a lot. Alodine, chemical converting aluminum parts for aircraft. Now I am allergic to stainless steel, hope I didn't kill myself off, guess we'll find out.