One of my many projects is to restore the (large number of) 1930s steel, Crittall, casements in my house, and the wooden frames they sit in. The problems are that the windows have leaded lights and haven't been maintained so many have been nibbled at the bottom by the rust mouse, which lets-in the rot mouse. I've been getting the steel sand-blasted to get the paint and rust off, cutting-out the rotten bits (Rage2 chop saw
- brilliant!) and welding-in new sections using a couple of spare casements for sources of metal. The steel is a modified H section and about 4mm thick so I'm bevelling the edges to about 1/2 thickness and doing butt joints, either in-line or mitred at 45 degrees. The problem is that the steel seems to slightly "run away" at the edges of the weld, leaving a small pitt. When I look closely while welding it seems to be generating small balls (not MIG spatter) but I'm fairly certain it isn't galvanised. Any comments or advice from experienced MIG welder wielders?