What is Brass Rot?

I had a model I'd built in 1967 at the NRG show. As I was cleaning it, I noticed that the linen thread was rotting where it came in contact with brass eyes. I first thought that I'd left some silver-solder flux on the eyes, and this had attacked the linen, but then I spoke to Roger Cole who said that he'd seen the problem - he got around it by blackening all brass and then givin it 3 coats of clear varnish. He thinks that the oxidized copper can absorb moisture and form weak acids. Tom Fordham says he's seen it on some of the models he's restored at the SF Maritime Museum, both in brass and in copper.
{John O. Kopf}

I have not actually seen it, but have heard about the problem. It only happens when corrosion occurs on the metal, which will rot any rigging coming in contact with it. If the metal is given a protective coating, then corrosion would be essentially prevented. Another possible culprit might be trace residues of oxidation salts continuing the reaction. If this process is not thoroughly neutralized, the residual salts will attract moisture, forming an acid, and thus the eating away of any rigging line coming in contact with same.
{Phil Krol}

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