Yeah, I know this has been done before. But I have a newfound board from "the basement" that really needs help (see pic).

I've seen about the LET & Body Shutz approach, which isn't bad. But I'm curious about 2 things:

1. Whatever that tar/pitch/bakelite crap is on the backside - how do you soak it off without damaging the body of the panel or the topside electronics?

2. Those who've done the LET & Shutz thing - how's it lasted after time?

This one is dry & cracked on the underside - gooey & tacky up top (though it WAS stored upside down for 15 years).
Pat

i just chipped it out with a pocket knife and a screw driver. it cleaned up good, i'm gonna resolder the connections the epoxy the backside.

I just chipped mine out and after cleaning refilled with liquid electric tape(black) I first filled any holes with elec dope. works great!

Yeah, I know - you can do it with "other" stuff.

But, I'm a purist & want to know what the Factory used. I'd like to use it again - lasted 35 years!. Hell, I'll be 95 when it needs to be redone again! By then I can probably stuff it with dried Pampers!

After experimenting with all kinds of solvents (none of which seem to do anything),
I found (totally by accident) that the tar stuff chips up and scrapes off
fairly easily when its cold. (I was trying this during the winter in the garage).
The cold temperature hardens the tar and makes it very easy to scrape off.

So I would recommend putting it in either the refrigerator or freezer
a while prior to scraping it off.

I bought a few dental picks but it turned out that the best tool is a flat blade
screwdriver that is the width of the traces. Just push it into the groove
of the trace and slide it along as it chips off the tar.

Hope that helps.

--- bill

Interesting! I can see the cold FINALLY being of benefit!

I remember reading sometime back that dropping it on concrete from about a foot up does some good too.

Does anyone know what that original stuff was?

I think it may actually be tar. You could try remelting it. I would suggest the double boiler method.

Alittle thread hijack.

Has any one ever used potting compound in place of the tar?

Oh my... you're older than dirt!

(hit and run, hit and run!)

That is what I suggested in the first thread......

I would either try that or simply fill it with epoxy. Fiberglass resin would probably work just as well and I believe you can tint that any color you want.

Yeah, maybe - but MY dirt is cleaner than yours!! And, older! So, that makes you.... newbier dirt! So, there!
Pat

we have red dirt

OK, I've heard the term but not sure what potting compound is. Maybe I missed this is an earlier thread, but please expound (if just for me).
Pat

Bunch of potting compound info

Potting compound can be most anything but as of recent it's basically expoxy based (for the most part). Lots of manufacturers use it to hide simple components and keep ideas from beinf stolen but for the most part, it keeps components from rattling or vibrating etc.

It's basically what you're looking for but a more modern example. You might be able to get one that fits the description of what's in there now but, I'd be more inclined to use a black epoxy. It would probably look identical to the stock when it was new and it would retain that look.

Like anyone is really going to look at the bottom of your relay board at a CW contest..... Go clean something with a cotton swab.

Leave Pat alone... he can't help it