05-25-2008, 11:14 AM
Sorry Randal, but I have to disagree when it comes to the use of silicones in electronic equipment...
I used to use silicone to seal Philco tone controls and those small rectangular metal case condenser cans that mount with two tabs. I stopped when a customer returned a set because it had stopped working. The fault was traced to...a metal case condenser sealed in silicone that had failed. That day I switched to hot glue for tone controls, and to hold caps in place in those metal case condensers.
Another tech told me some time ago some horror stories of how electronic parts that had been sealed in silicone would later fail...and how the silicone had caused the failure by eating through the copper.
In addition to all this...black silicone may be OK for going around the perimeter of a speaker cone, but you should be aware that some black silicones have conductive material in them! A certain Philco (non) "expert" used to fill all of his bakelite blocks with this stuff, and he swore it was great. (Chuck knows who I am referring to, and no, it is not Chuck!!!) It's unbelievable to me. I would hate to be the one having to troubleshoot some of his radios later when they mysteriously failed!
(As a side note, there is no reason whatsoever to reseal a bakelite block once it has been rebuilt. It is a waste of time. No-one is going to look into them, and besides, by leaving them unsealed, you have made things easier for the next tech who may have to rebuild it again in another 50-75 years.)
Now, when it comes to JB Weld, I can agree that it is a true asset to any serious radio restorer.
I used to use silicone to seal Philco tone controls and those small rectangular metal case condenser cans that mount with two tabs. I stopped when a customer returned a set because it had stopped working. The fault was traced to...a metal case condenser sealed in silicone that had failed. That day I switched to hot glue for tone controls, and to hold caps in place in those metal case condensers.
Another tech told me some time ago some horror stories of how electronic parts that had been sealed in silicone would later fail...and how the silicone had caused the failure by eating through the copper.
In addition to all this...black silicone may be OK for going around the perimeter of a speaker cone, but you should be aware that some black silicones have conductive material in them! A certain Philco (non) "expert" used to fill all of his bakelite blocks with this stuff, and he swore it was great. (Chuck knows who I am referring to, and no, it is not Chuck!!!) It's unbelievable to me. I would hate to be the one having to troubleshoot some of his radios later when they mysteriously failed!
(As a side note, there is no reason whatsoever to reseal a bakelite block once it has been rebuilt. It is a waste of time. No-one is going to look into them, and besides, by leaving them unsealed, you have made things easier for the next tech who may have to rebuild it again in another 50-75 years.)
Now, when it comes to JB Weld, I can agree that it is a true asset to any serious radio restorer.
--
Ron Ramirez
Ferdinand IN
