Help with shrinking metal

[G.Pope]

I have a few of the vent grates on the bottom of a vmc-81 that are a little distorted ( a little wave, no bends or kinks...just not straight enought) and need a little strinking. I have never done this and was wondering how you guys do this. I have a small MAP gas torch and a mig welder if either of these items help. The machine is down to metal so no problem with working on it.

Thanks

[sodaworks]

I normally use a hammer and dolly for stretched louver vents.