I deal with 'zinc pest' issues all the time in my restoration business, particularly with pre-war items. What saddens me the most is when potential clients come to me with their 700Es and 763Es steamers, that have deteriorated beyond repair and ask me to fix them- which, of course, I can't..
Other than 'replace the part' I have not yet found a way to actually repair 'zinc pest'. I don't think it'll ever be possible. And, as almost everyone in the model train community knows, new, old stock undamaged 700E & 763E boilers are harder to ferret out than a winning lottery ticket.
But I want to bring up a warning here, regarding post-war Lionel GG-1s, particularly the 1963 Tuscan 'decal solid-stripe' versions. I've seen more than my share of these locos with 'zinc pest' affecting the 622-type motors that GG-1s use, on the bottom motor casting; also many of the twin motor GG-1 power trucks are likewise affected, rendering the loco inoperable..
A word to the wise: Please use caution when purchasing one of these locos, as replacing two motors and two magne-traction power trucks can be very expensive.
The Lionel Corporation was in almost total disarray by 1963, so part assemblies and sub-assemblies may not have been manufactured at the factory, but out-sourced. Also, Lionel's engineering staff had been let go years before, so quality control definitely suffered. Before considering a purchase, look for those tell-tale hairline cracks in the GG-1 truck casting and run, do not walk away from any GG-1 that appears to suffer from 'zinc pest'. Unless, of course, the engine is for sale very cheap and you need it for some of the other parts that are not affected. Chances are, if one of the trucks or motors from the engine are bad, the others will be too. Sometimes a GG-1 that has only been mildly affected with 'zinc pest' will still run; but, guaranteed it will only get worse - and eventually it will be rendered inoperable!
Good luck to all.
-Len Carparelli
