Way to dissolve the evil brown glue?

[Agent24]

I have a ceramic capacitor that I wish to read the value of. I can't do this because it's covered in evil glue which is obscuring the markings. Also I do not trust the glue to not interfere with measuring it on a capacitance meter.

Is there something I can dissolve the glue with that will hopefully not remove the paint from the capacitor as well?

I normally scrape the glue off with a blade but that is not really an option here.

[mockingbird]

Re: Way to dissolve the evil brown glue?

My favorite "poor man's" solvent is charcoal starter fluid. You can also use kerosene in a pinch, but kerosene is a dirty hydrocarbon and the stench lingers.

[goontron]

Re: Way to dissolve the evil brown glue?

carb cleaner. or gasoline in a pinch.

[kasfamily]

Re: Way to dissolve the evil brown glue?

Heat gun helps too.

[rhomanski]

Re: Way to dissolve the evil brown glue?

For the corrosive glue Sansui used to use I remove it with acetone. It has taken the printing off of newer capacitors though. On the old Sansui's I really don't care because I'm in there to replace them anyway.

[popeye]

Re: Way to dissolve the evil brown glue?

heat it up to 120deg c it will just peel off then

[stj]

Re: Way to dissolve the evil brown glue?

acetone or xylene.
if you go xylene - do it outside, that stuff will damage your brain!!

also, know that you can melt plastics and remove paint with these - you WILL take the stripes off resistors for example.

i think most brake fluid is xylene based btw.
if it smells sweet - you shouldnt be smelling it!!!

[eccerr0r]

Re: Way to dissolve the evil brown glue?

brake fluid is typically glycol... xylene would be way too volatile/flammable for a high heat application such as brakes. But xylene is a great solvent - for nonpolar materials. Does nothing for water based material.

A lot of the times the glue is chosen such that any solvent used will also dissolve the electronics underneath. Pretty much only mechanical removal is the only option, if heating it doesn't help.

I would at least try carburetor cleaner, if you don't have VOC regulations near you, methylene chloride in the "cheap" formulation is a good solvent too, for nonpolar materials. Else acetone in the VOC regulated formula also works. Both these can eat some types of plastics.

Need to determine what kind of glue it is - that's the underlying problem. I haven't found anything that dissolves set epoxy...

[stj]

Re: Way to dissolve the evil brown glue?

my mistake, i meant brake / carb cleaner not fluid.

[stj]

Re: Way to dissolve the evil brown glue?

gel paint stripper slowly desolves epoxy.

[eccerr0r]

Re: Way to dissolve the evil brown glue?

I got some brake cleaner and forgot if it was the low VOC formula or not. Seems it's mostly heptane and other non oxygenated organics. Yeah, might have had xylenes in it.

Might have to try some paint stripper or equivalent, looks like some are made of methylene chloride/dichloromethane too, or even sodium hydroxide (all of these are nasty). These can cause damage to the circuit which is the main reason why I haven't tried...

[stj]

Re: Way to dissolve the evil brown glue?

how about MEK (methyl keytone) ?
another one for outside use.

[rhomanski]

Re: Way to dissolve the evil brown glue?

If you use MEK, wear gloves. I've watched 5 people die from brain tumors from using it.

The first was my lead mechanic in 1991. He took a weeks vacation, I asked on Monday where he was and they said, "You didn't hear?". Words I began to dread over the years. He lost his peripheral vision and was dead a week later.

[Agent24]

Re: Way to dissolve the evil brown glue?

Heat gun helps too.

heat it up to 120deg c it will just peel off then

I decided to try this idea first as being the least messy and least likely to remove the paint as well. I used my hot air rework tool on lowest (160°C) and pulled the glue off with tweezers. Worked very well, no damage to the capacitor.

I heard the horror stories about MEK in high school. Wouldn't go near the stuff...