For those new to this saga, I'm practicing welding. No , I never
expect to approach an a/c, but I'd like to learn to apply a patch, do
a splint, etc. IAW 43.13.

I took some mild steel (.037) and bent it, then straightened it (cold)
as shown in the EAA 'Aircraft Welding' book.

Question: when the bend was straightened, two bulges on either side
of the bend still remained. Are those removed cold, or with heat? -
Mike