Removal of conductive paint from glass - Page 1
Forum section: electronics / general

author: dexters_lab
author_rank: Unknown
timestamp: September 22, 2016, 08:47:26 am
content: i have a photomultiplier here i'm trying to remove some brown/red conductive paint from and it's proving difficult, what i thought would be a 5 min job isn't.the pmt is junk, i just want to remove the red paint from the back and the neck to make it more ornamentalso far the most productive method has been to just use a sharp blade to scrape it off but i have also tried:white spirit, ethanol, petrol, cellulose thinners, IPA, nitromores paint stripper and various other solvents i found but nothing touches iti do have dichloromethane, but that would probably decompose the plastic plug end and probably detach the blue filter that's bonded to the front. I would also rather not waste that much of my dichloromethane!any suggestions?

author: daqq
author_rank: Super Contributor
timestamp: September 22, 2016, 09:43:59 am
content: Acethone applied targetedly by a small swab?

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: September 22, 2016, 09:49:26 am
content: Few other things to try:* Give it the ultrasonic cleaner treatment. It might take a while before the paint will start flaking off.* Perhaps give it an acetone bath for a good couple of days. Warning, do not allow acetone to make contact with plastic parts! Only immerse the glass bits.* Bath of potassium hydroxide or sodium hydroxide (aka caustic soda). The former is harder to get but it is much more potent. Warning, highly corrosive, it will destroy aluminium. Turns your nails into soap. Handle with tick rubber gloves and good eye protection.

author: Psi
author_rank: Super Contributor
timestamp: September 22, 2016, 10:05:10 am
content: maybe you need one of these

author: daqq
author_rank: Super Contributor
timestamp: September 22, 2016, 04:06:14 pm
content: QuoteBad bad idea... if nothing else it's a glass tube with delicate bits inside. You'd probably end up with a broken bulb and lots of photomultiplier bits in the cleaner.

author: AntiProtonBoy
author_rank: Frequent Contributor
timestamp: September 22, 2016, 04:19:51 pm
content: Yeah you're probably right, although I would've thought that ultrasonic cleaners work at water/solid interface where cavitations are produced to dislodge material on the surface. Takes a lot of energy to break glass, whose resonant frequency must be close to one of the harmonics of the ultrasound.Quote from: Psi on September 22, 2016, 10:05:10 amThis thing is hypnotic. I want one... for, um, reasons.

author: rdl
author_rank: Super Contributor
timestamp: September 22, 2016, 04:27:52 pm
content: Quote from: dexters_lab on September 22, 2016, 08:47:26 amMost paint would have be affected, at least a little, by one or more of those.I wonder if it's actually paint? Maybe it's some kind of glaze or ceramic that's actually heat fused into/onto the glass surface.

author: firewalker
author_rank: Super Contributor
timestamp: September 22, 2016, 04:35:46 pm
content: Hydrofluoric acid and/or Piranha solution?Alexander.

author: PartialDischarge
author_rank: Super Contributor
timestamp: September 22, 2016, 04:40:39 pm
content: Quote from: firewalker on September 22, 2016, 04:35:46 pmHF will eat the glass, he needs nitric acid in around 30%-60% concentration.

author: Cyberdragon
author_rank: Super Contributor
timestamp: September 22, 2016, 06:13:18 pm
content: Quote from: AntiProtonBoy on September 22, 2016, 04:19:51 pmThere are several of these machines available, just look for laser paint stripper.http://www.cleanlaser.de/wEnglish/produkte/high-power-cl-1000.phpJust don't burn the house down.

author: dexters_lab
author_rank: Unknown
timestamp: September 22, 2016, 06:45:22 pm
content: quite a few suggestions there, thanks!i think i will try some acetone first off, cheap and easily available

author: _Andrew_
author_rank: Regular Contributor
timestamp: September 22, 2016, 06:56:10 pm
content: Have found in the past when using cellulose thinners to clean of old anti corona lacquer from crt's the thinners were more than happy to start removing the conductive paint as well.

author: tggzzz
author_rank: Super Contributor
timestamp: September 23, 2016, 06:57:58 am
content: I dismembered a broken CRT, and found part of it was opaque ceramic, not glass.FFI, including pictures, seehttps://entertaininghacks.wordpress.com/2016/03/09/rescuing-a-broken-tektronix-465-crt/

author: dexters_lab
author_rank: Unknown
timestamp: September 23, 2016, 11:03:41 am
content: Quote from: Alex Eisenhut on September 23, 2016, 01:22:05 amyea, the knife blade works ok, it's very very hard though and the rounded edges of the glass make it hard work to get off.Quote from: tggzzz on September 23, 2016, 06:57:58 amit's paint for sure, you can see where i have removed some of it in my picture