How to remove white adhesive compound/glue from components?

[halleffector]

Please consider the following image:



What is the white compound called? Simply "glue", or something else?

Most importantly, how can I easily get it off? This is a tightly packed power supply which has among other things a vertical daughter board soldered directly into the main board. It would be nice to get those bad capacitors out of there without needing to desolder more components than necessary, and the white compound is a big show stopper for that.

 

[jpanhalt]

"Something else." Most likely a room temperature vulcanizing elastomer (RTV) or silicone. Hot melt is sometimes used for that too, but doesn't usually flow like that.

Removal is usually by just pulling and scrapping (i.e., mechanical). There are silicone removers that denature the silicone. The ones I have checked all contain sulfonic acids, which is a strong acid (like sulfuric) attached to a long carbon chain that allows it to penetrate the silicone. It might work for RTV rubbers too, but be sure it is washed off well.

Beware of the so-called silicone removers that are not like that. If you get most of it off, I have used naphtha or mineral spirits with isopropyl alcohol (1:3) to removes the last vestiges of silicone. The naphtha acts as a lubricant in that mixture to keep the rubber particles from sticking as they are rubbed off.

I wound recommend mechanical removal followed by clean up, if necessary.

John

Edit: Here's the silicone remover I use: **broken link removed**

Mossenbach's (at HD and others) is garbage.

 

[Nigel Goodwin]

It would be nice to get those bad capacitors out of there without needing to desolder more components than necessary, and the white compound is a big show stopper for that.

You simply just cut the silicon around the component (using a knife or side-cutters - I usually use side-cutters), then unsolder it and pull it out - I've replaced hundreds (if not thousands) of capacitors that were stuck down using silicon rubber.