On Sept. 27 I asked if anyone knew of a product similar to one I had found on a Dutch site: a primer which, they claim, you can weld through and is particularly suitable for welding tubular stuff where you can't get at the other side of the weld to rust-proof it after it has been made. Michael Pergiel put me onto 3M's Weld-Thru Primer and I bought a can to try it.

Well, true, you can weld through it, but the stuff does get burned off at the weld and on the other side of the weld in an area about twice the size of the weld itself, and you have to repaint the welds. So, although it may be useful for lap-welds to mitigate rusting between the lapped surfaces, for butt-welds it provides little advantage over regular zinc spray, which is a lot cheaper. BTW, consultation with people who know more about welding than I has convinced me that the claims made for the Dutch product, *INOX SPRAY,* are, probably, overstated.

This has been a public service announcement for the benefit of all optimists like me -- just ignore them if they say you're naive and keep on hoping.
Bob S.