Potting to protect printed circuits ?

NO, dumbass. When one takes on a potting operation, one doesn't just dopily stumble into the process like you would.

The CLEANED assembly MUST be baked at 60C for at least 45 minutes, and even a vacuum helps. Once potted, a vacuum is ideal to remove air in the potting matrix. Prior to potting, the vacuum boils any water trapped in the hygroscopic PCB strata.

I cannot believe some of the stupid crap some of you dopes pop off with here.

General Electric makes several RTV silicone based 2-part potting materials as well, that are "more serviceable" than the polyurethanes, which adhere like glue (that's a good thing where that type gets used).

The term is SHEAR, Johnny. Hard potting a PCB assembly ... has only been brought up by the one dope that would be stupid enough to do it... YOU!

Not all epoxies and not all "hard setting" potting materials are exothermic.

Still, most of us intelligent folks were actually referring to the materials that the industry commonly DOES use, not your petty little nightmares.

You are worse than Obama!

Ball Incorporated in Denver area makes spherical "circuit assemblies" that are a hairball of parts.

Potting operations are easy as long as one thinks through the process first, and develops a build plan, and then debugs that plan during early execution cycles.

Board re-spins cost considerably more than a nickel, chucko.

Any time you want to meet, pussy boy.

Cool. Post your name and address, and I'll be there.

Otherwise, you remain a coward.

John

I know it cost more, but not x10 or x20. The board already has die encapsulation elsewhere, so SMT parts encapsulation should not cost much more.

G'ahead, re-read my post with comprehension as one of your objectives.

Dimbulb has no comprehension.

A variant of that is the old cordwood construction scheme, where parts would go between two circuit boards, like being the contents of a sandwich. Used for the military loooong before SMT parts. Transistors and ICs would "hang" below the top board, and sit on the bottom board, with resistors, capacitors, etc being the pillars that also make as spacers. So, with SMT parts, the spacing is a lot less and presumedly only wires would go between the boards.

A lot like the cordwood system that i previously mentioned.

I'm not talking so much about the cost of potting, I'm talking mostly about the cost of installing the piggyback parts by hand. Any second-operation process gets enormously expensive very quickly.

We frequently do ECOs on our customers' boards, and the cost of swapping four or five components, or cutting and jumpering a couple of traces, or piggybacking stuff as you're thinking of doing, very often exceeds the original assembly cost.

And impossible to repair.

Thanks! Rich

Sure sounds like "messy and expensive" to me.

John

Only with a total dweeb like you doing the analysis.

Assemblers... even proto-assemblers are cheap. Re-spins are not.

You sport about 1/1000th the brains of the man I once knew named Smitty. You be pretty shitty... Smitty. You be lame.

Standard assembly process, standard clean process.

The only thing added is a bake step and or vacuum. Then off to potting area, where only finger paint retards like John Larkin cannot perform operations without getting things "messy".

It ends up costing about $2 per cubic inch, labor and all.

You are pathetic, Johnny.

You're absolutely clueless, AlwaysWrong. Though you may be cheap, people are *expensive*.

Not quite like DimBulb's mommy; shitty, but not pretty.