HOWTO remove silicone w/o scraping?

Arcturius · 12-01-2002, 01:36 PM

Does anyone know of a method to remove silicone without cutting or scraping it off? An electronics-safe solvent would be ideal.

(I need to redo the 'winterizing' on a board of mine with tighter tolerances...)

Since87 · 12-01-2002, 03:36 PM

Toluene is the solvent in the silicone conformal coating my employer uses. It can dissolve the silicone without harming electronic components. You don't want to breath it though.

Arcturius · 12-01-2002, 05:03 PM

Quote:

Originally posted by Since87
You don't want to breath it though.

No kidding; I have some model aircraft glue that contains toluene. The warnings cover the entire backside of the tube (about 1.25"x5", 8pt font...)

Do you know of a brand name or product type so I could look for it locally? I found it available online in a pint can: http://www.riverraiders.com/accessor...aftrepair.html
but I doubt I need that much (and I'm impatient, so I want to get it locally.)

Also, how do you handle it where you work? I found some people recommending neoprene gloves be used, but according to Cole Parmer, toluene has a devastating effect on neoprene.

I also found something interesting in my searching, a chemical compatibility database:
http://www.coleparmer.com/techinfo/ChemComp.asp

Thanks in advance!

Since87 · 12-01-2002, 06:40 PM

The production people use plain old rubber gloves and a ventilation hood. For the most part there is no need to come in contact with it, because they are just dipping circuit boards and transformers in it, and then hanging them up to dry.

Be warned if you do this, it is just going to turn the silicone into a gooey slimy mess. You can do this to get stuff unstuck, and to get rid of blobs, but you're not likely to get the stuff completely off this way.

An "orange stick" is a good way to scoop the goop up. (A wooden stick with sort of a chisel tip you can get at the drugstore.) An orange stick reduces the risk of scraping things up.

I don't know for sure where to get it. I think you might be able to get it at a Home Depot type place, although they're likely to sell it by the gallon.

Arcturius · 12-01-2002, 06:49 PM

Ok, thanks!

Can O' Beans · 12-01-2002, 11:03 PM

We used toluene to remove silicone at an electronics manufacturer I worked at.

And about the breathing... Guy used to fill the smaller containers out of the large barrel. He would soak a rag in it, then huff it when he got back to his workstation. That guy was beyond burnt-out

MadDogMe · 12-02-2002, 04:28 AM

Man!, we used to pull stunts like that when we were wild eyed spikey hair punkrockers!(circa 1984),but only when the stars were out(oh me oh my!, there's a light_in_the_sky!), but I would'nt wanna go there now!, and at work?, urrgggghhhh!. how old was this dude?...

Brians256 · 12-02-2002, 12:52 PM

I am very surprised that toluene dissolved silicone! It really works on RTV sealants?

As for huffing, "A fool and his brain cells are soon parted." I think Benjamin Franklin was the original quote-meister who said that a fool and his money are soon parted. However, I like my update to it.

Since87 · 12-02-2002, 01:12 PM

Quote:

Originally posted by Brians256
I am very surprised that toluene dissolved silicone! It really works on RTV sealants?

I can't say for certain. My experience has been with silicone conformal coatings dissolved in toluene. Toluene will definitely dissolve the conformal coating again after it has "dried". I don't know whether RTV cured silicone is substantially different from the silicone used in conformal coating.

bigben2k · 12-02-2002, 01:20 PM

I don't think anythink would dissolve RTV silicone sealant, but Toluene might be worth a shot.

Arcturius: tell us more! Is this a thick layer of silicone goop, or is it conformal coating?

Keep in mind that toluene might dissolve a number of other plastics on a motherboard, including the PCI slots, the IC chips, the CPU socket, etc... I would like to think that they are safe, but can't say for sure.

crane · 12-02-2002, 01:27 PM

Naptha will soften cured RTV sealant... it can be found easily in the little container labeled "goof off". It sure isn't electronic safe as it attacks plastics with a vengeance.

EDIT=Sorry...its Xylene,not naptha in goof off.
Its all Methyl Ethyl Badshit, if you ask me.

Arcturius · 12-02-2002, 08:02 PM

What I'm most concerned about removing is some white silicone that was used as a glue for neoprene on the back of the board. The neoprene is somewhat torn, and it is blocking repair work on the wires for a Palomino die temp reader, and it's also a little thick for some of the plans I have for this board.

Ideally, I would like to clean up around the socket as well, but I've mostly gotten that cleaned up with a razor blade and a soft plastic scraper.

I would like to have it all pretty and clean again though.

bigben2k · 12-02-2002, 08:13 PM

I would try a Dremel and wire brush, but only on a very low speed setting, and I'd test it first.

I believe that there's a plastic wire brush for the Dremel.

If that's not an option for you, I'd stick to the razor blade. You could try a toothbrush, but I doubt it would do much. Maybe... if you trimmed the bristles, so that they're stiffer, you might get lucky.

Since87 · 12-02-2002, 08:31 PM

This link shows suitability of various materials as o-rings for use with toluene.

Both neoprene and silicone are listed as "poor" candidates as O-ring material. (Maybe meaning both will dissolve.)

12-01-2002, 01:36 PM	#1
Arcturius Cooling Savant Join Date: Aug 2001 Location: Chippewa Falls, Wisconsin Posts: 294	HOWTO remove silicone w/o scraping? Does anyone know of a method to remove silicone without cutting or scraping it off? An electronics-safe solvent would be ideal. (I need to redo the 'winterizing' on a board of mine with tighter tolerances...)

12-02-2002, 01:20 PM	#10
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	I don't think anythink would dissolve RTV silicone sealant, but Toluene might be worth a shot. Arcturius: tell us more! Is this a thick layer of silicone goop, or is it conformal coating? Keep in mind that toluene might dissolve a number of other plastics on a motherboard, including the PCI slots, the IC chips, the CPU socket, etc... I would like to think that they are safe, but can't say for sure. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

12-02-2002, 01:27 PM	#11
crane Cooling Neophyte Join Date: May 2002 Location: so cal Posts: 82	Naptha will soften cured RTV sealant... it can be found easily in the little container labeled "goof off". It sure isn't electronic safe as it attacks plastics with a vengeance. EDIT=Sorry...its Xylene,not naptha in goof off. Its all Methyl Ethyl Badshit, if you ask me. __________________ dirt rules Last edited by crane; 12-02-2002 at 05:59 PM.

12-02-2002, 08:13 PM	#13
bigben2k Responsible for 2% of all the posts here. Join Date: May 2002 Location: Texas, U.S.A. Posts: 8,302	I would try a Dremel and wire brush, but only on a very low speed setting, and I'd test it first. I believe that there's a plastic wire brush for the Dremel. If that's not an option for you, I'd stick to the razor blade. You could try a toothbrush, but I doubt it would do much. Maybe... if you trimmed the bristles, so that they're stiffer, you might get lucky. __________________ WBTA (Water Block Testing Alliance) Nordic Hardware WC 101

12-01-2002, 03:36 PM	#2
Since87 Pro/Guru - Uber Mod Join Date: Sep 2002 Location: Indiana Posts: 834	Toluene is the solvent in the silicone conformal coating my employer uses. It can dissolve the silicone without harming electronic components. You don't want to breath it though.

12-01-2002, 06:40 PM	#4
Since87 Pro/Guru - Uber Mod Join Date: Sep 2002 Location: Indiana Posts: 834	The production people use plain old rubber gloves and a ventilation hood. For the most part there is no need to come in contact with it, because they are just dipping circuit boards and transformers in it, and then hanging them up to dry. Be warned if you do this, it is just going to turn the silicone into a gooey slimy mess. You can do this to get stuff unstuck, and to get rid of blobs, but you're not likely to get the stuff completely off this way. An "orange stick" is a good way to scoop the goop up. (A wooden stick with sort of a chisel tip you can get at the drugstore.) An orange stick reduces the risk of scraping things up. I don't know for sure where to get it. I think you might be able to get it at a Home Depot type place, although they're likely to sell it by the gallon.

12-01-2002, 06:49 PM	#5
Arcturius Cooling Savant Join Date: Aug 2001 Location: Chippewa Falls, Wisconsin Posts: 294	Ok, thanks!

12-01-2002, 11:03 PM	#6
Can O' Beans Cooling Savant Join Date: Aug 2002 Location: Pa - USA Posts: 264	We used toluene to remove silicone at an electronics manufacturer I worked at. And about the breathing... Guy used to fill the smaller containers out of the large barrel. He would soak a rag in it, then huff it when he got back to his workstation. That guy was beyond burnt-out

12-02-2002, 04:28 AM	#7
MadDogMe Thermophile Join Date: Aug 2002 Location: Just shut up ;) ... Posts: 1,068	Man!, we used to pull stunts like that when we were wild eyed spikey hair punkrockers!(circa 1984),but only when the stars were out(oh me oh my!, there's a light_in_the_sky!), but I would'nt wanna go there now!, and at work?, urrgggghhhh!. how old was this dude?...

12-02-2002, 12:52 PM	#8
Brians256 Pro/Staff Join Date: Oct 2001 Location: Klamath Falls, OR Posts: 1,439	I am very surprised that toluene dissolved silicone! It really works on RTV sealants? As for huffing, "A fool and his brain cells are soon parted." I think Benjamin Franklin was the original quote-meister who said that a fool and his money are soon parted. However, I like my update to it.

12-02-2002, 08:02 PM	#12
Arcturius Cooling Savant Join Date: Aug 2001 Location: Chippewa Falls, Wisconsin Posts: 294	What I'm most concerned about removing is some white silicone that was used as a glue for neoprene on the back of the board. The neoprene is somewhat torn, and it is blocking repair work on the wires for a Palomino die temp reader, and it's also a little thick for some of the plans I have for this board. Ideally, I would like to clean up around the socket as well, but I've mostly gotten that cleaned up with a razor blade and a soft plastic scraper. I would like to have it all pretty and clean again though.

12-02-2002, 08:31 PM	#14
Since87 Pro/Guru - Uber Mod Join Date: Sep 2002 Location: Indiana Posts: 834	This link shows suitability of various materials as o-rings for use with toluene. Both neoprene and silicone are listed as "poor" candidates as O-ring material. (Maybe meaning both will dissolve.)

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