When dealing with gauge numbers. The higher the number the smaller or thinner the material. So if a break is good for 28 gauge it WILL NOT bend 18 gauge. Find a HVAC shop to bend it up for you
OOOOPS, sorry----That's what I get for being a woodworker all my life.
The reason I looked up what a siding brake would handle was I thought that kind of metal would be too thick for a siding brake, but then I ran into the trick metal-working number system
, and thought I was wrong in the first place---LOL. Oh well---Thanks for the correction Sparky.
Duhhhhh,
Bear