On 21/10/2020 21:53, newshound wrote:
On 21/10/2020 21:39, wrote:
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?

I thought that all Crittall steel windows were hot-dip galvanised.

Correction, I didn't realise they actually started making steel frames
in the 1880s; Wikipedia suggests they started galvanising in 1939
(although I suppose they could have contracted that out).

I'm pretty sure mine are, but that's post WW2.