What is "lead sickness"?

First of all, it has NOTHING to do with the toxic properties of lead!

Model fittings which contain lead have a bad reputation of frequently "decaying" after 10-20 years. Current thinking is that the cause is the presence of Antimony in the alloy. This metal is used to make the molten metal more fluid. Apparently, it crystallizes out of the melt as the metal solidifies; the result is that on the crystalline level dissimilar metals are in contact (if they didn't separate, the metals would be mixed at the atomic level). The result is that in the presence of water (or other chemicals) a galvanic reaction is set up (a tiny battery is formed) which causes chemical reactions to occur; the lead oxidizes into lead monoxide PbO, accompanied by the formation of antimony hydride SbH₃ (stilbine) which is a gas and escapes into the atmosphere. Most "soft" solders and "type metal" contain both lead and antimony.

An alternative is "Britannia metal" which is 93% tin, 5% antimony, and 2% copper.

"Traditional" Pewter can contain up to 7% antimony, 20% lead, 4% copper, and the rest tin. Modern Pewter is sold as "lead free", and so probably doesn't have the problem. (This description is based on a letter by William G. Webb in Model Shipbuilder #87.)
{John O. Kopf}

For some reason, many lead compounds commonly used in making model ship fittings deteriorate after 5 to 20 years, actually turning to a powdery substance. Therefore, almost every maritime/naval museum I have had contact with specifies that no lead alloys may be used in construction of models.

Preferred substitute is called "Britannia Metal," and no, I don't know the make-up, but Bluejacket, among others, advertise parts in this metal.
{RAlcorn824}

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