by Doug Coulter » Sun Oct 03, 2010 9:38 pm
Good point, Joe. Yes, probably it should be removed, and maybe replaced with something lower vapor pressure and more inert (copper, say). Iron is not so great in vacuum, once clean (which vacuum will do) and then exposed to air, it rusts fast -- then believe it or not, the rust decomposes in vacuum and slowly gives off oxygen. If it's going to get hot, Zinc is going to make quite a mess. This hasn't come up in the ones I've done so far -- the model A plug isn't plated (it's gun-blued!) and the other one I did was submarined into the flange I had it in, so wasn't exposed too much. Lucky it's easy to get rid of -- weak HCl is the ticket there.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.