Nail Varnish

[col]

I was reading something in a guitar magazine about amp repair where they recommended that all solder joints be covered in clear nail varnish to prevent them 'drying out'. Should this apply to DIY pedals too? What actually happens when a joint dries, does it mean that the metal oxidises or forms large crystals and how does nail varnish perevent this?

Col

[petemoore]

This is the first I've heard of that.
 I've never seen it used either.
 If you ever decided you wanted to reflow the solder joints, this would make it difficult/impossible to do.
 I suppose it would look 'kool, but I'm sticking with the solder 'finish'.

[Eric H]

You'll see nail polish on the solder connections in old hand-wired Marshall amps. It was a quality-control measure to show that the joints were inspected, and correctly done. The dry-joint thing is hogwash

-Eric

[Torchy]

The solder used in old equipment did not have rosin core, and the flux turned acidic on contact with the air over a period of time. This would gradually lead to joint weakness and an increase in electrical resistance. The varnish was to prevent oxidation of the flux in the joint. With the introduction of neutral rosin-core solder, the varnish (as Eric said) continued as a q.a. measure (and looked damn pretty too )

In the RAF we used to varnish screw-terminals for the same reason (oxidation and a crude thread-lock).

[The Tone God]

Sometimes the varnish or a dye of some sort is put on things like bolts and screws to serve as an indicator that someone has tampered with equipment and therefore violated the warranty.

Anyways nail polish, especially in DIY uses, would be a waste. You could just spray varnishing the board in seconds.

Andrew

[jmusser]

That's been my only experience with it to. I have seen something like nail polish or varnish, usually used on screw heads, to see if you've been into the works. I would imagine because of warranty. One thing I have seen though, was whole PC boards dipped in a varnish type stuff, back when I was in telecommunications. I asked around about this (because you had to scrape the mess off to do any mods), and they said it had to do with stopping a fungus that would actually grow on the boards, if they were installed out in the tropical locations. That sounds weird, but I now work in the Natural Gas industry, and there are actually bacteria that live inside the pipeline! When you cut pipe apart or work on compressors, it comes out looking like gray/black soot.