"Potting" Inductors

[BobM]

For those of you adventerous enough to open up your Apogee and begin improving the crossover with replacement caps, better resistors and such, I have found something that will improve those big hand wound, loose wire inductors. MG Chemicals (4228-55ML) Red Insulating Varnish.

Here's a link to the Allied Electric site for this stuff:

http://www.alliedelec.com/search/productdetail.aspx?SKU=70125546

Basically, just brush/pour and brush it on the coils and let it soak in and get through them to the middle. You will probably have to turn them over once the top is dry and do the same to the other side to make sure it gets all the way through, and brush the edges also. It dried fairly quickly, in about 2 - 3 hours. Some DIY'ers say you can bake the inductors for 1/2 - 3/4 hour at 150 degrees in the oven to help this get through the coils and into the middle. I didn't find it necessary since it seeped all the way through. I used 3 bottles of this on the 4 large inductors in my Duetta Sig's.

Yes, it smells, so use adequate ventalation.

This is a far better solution than silicon, which really does nothing at all to hold things tightly together and doesn't penetrate the coils either. I guess you could use regular varnish or polyeurathane to do the same thing, but this stuff is made specifically for the job and it is relatively inexpensive.

Certainly a cheaper alternative to Erse air coil inductor replacements.

Good luck,
Bob