Conformal Coating

[ic-racer]

Anyone know if HAD used Conformal Coating on the back of his PC boards? Any guess as to the type? Silicone?

[UltraHookedOnPhonix]

Anyone know if HAD used Conformal Coating on the back of his PC boards? Any guess as to the type? Silicone?

I doubt Dumble used a conformal coating on the back of the PCBs. I think he just tinned the Copper traces as evidenced by the Dumblelator that Funk posted a while back. This way the Copper traces won't corode with age. By the way, conformal coatings, at least the acrylic lacquer that MG Chemicals offer (part #: 419B-340G) is, "very flammable".

Here's a picture of the relays I'm using for my ongoing BM build which I've tinned the traces on. I did this on all of the PCBs in the amp.

[IMG602]http://i205.photobucket.com/albums/bb17 ... Tinned.jpg[/img]

[Aurora]

Most types of conformal coatings are highly flammable while in the aerosole state,- as the solvent is usually of higher order, like toluene or similar. Also the drive gas in spray cans are often butane, propane or something similar. Once dry they are usually safe and good for the job intended - preventing corrosion....

[dr. who]

Anyone know if HAD used Conformal Coating on the back of his PC boards? Any guess as to the type? Silicone?

He sure used a lot of silicone on the top of his pre-amp boards

[ic-racer]

I doubt Dumble used a conformal coating on the back of the PCBs. I think he just tinned the Copper traces as evidenced by the Dumblelator that Funk posted a while back.

Ok, I did not see that one. I'll have to track it down.

Otherwise, unless someone else posts something better, I'll tin mine like you have shown.

Hey, nice layout on the PC traces


What size eyelet did you use on those boards?

[UltraHookedOnPhonix]

I doubt Dumble used a conformal coating on the back of the PCBs. I think he just tinned the Copper traces as evidenced by the Dumblelator that Funk posted a while back.

Ok, I did not see that one. I'll have to track it down.

Otherwise, unless someone else posts something better, I'll tin mine like you have shown.

Hey, nice layout on the PC traces


What size eyelet did you use on those boards?

I used Keystone #23 eyelets. Pretty sure that's what the D-man used for the relays. Tiny little $%@#! though!

Thanks, I'll never hand draw another PCB again. Results came out nice but it was very time consuming as you have to put more than one layer of Sharpie ink on in order for the etchant not to eat through prematurely.

Another reason I think Dumble tinned his PCBs is from the 97 ODS picture below, where you can see what appears to be solder flux that's settled on the edges of the Copper traces showing through the semi-translucent FR-4. Looks exactly like the aforementioned Dumblelator in which we know the traces were tinned. Also by doing this, I think the current carrying capacity of the traces is increased, no?

[BobW]

Conformal Coating is an overall PITA. Repairs require heating away the coating to de-solder. Since most amps are played and kept indoors, the coating is a moot point. Our amps aren't used in a MIL environment.