Patch panel tip.

[Nads]

When cutting out cancer, at least in small areas, utilize a cut off wheel. Dewalt makes great ones that fit in your trusty Chinese Harbor Freight angle grinder. Once the piece is cut out it can be used to make a template. The gap left from the cut off wheel width is perfect to weld in a new piece. The gap prevents metal warpage due to expansion and you get a nice strong weld.
I learned this after several years off using jig saws and tin snips and wasting years of my life.

[McGrath]

I use those at Work pretty regularly. They work Great, but you have to be careful with them. They will cut you so quick you won't even know what happened. They can also explode if you get one Hung-up. Safety Glasses are a Must.

[Anderson]

careful indeed. Those fuckers come apart, slice your skin, and scratch the shit out of any glass thats around.

but otherwise, thats all i use to cut out sheetmetal.

[lowsquire]

Ive found some ultra thin ones for my 5", they are about 1.5mm thick,awesome on sheet metal,with a little practice you can get cuts as straight as a shear,the thinness seems to help it stay straight...

[McGrath]

6" 1.5mm's are what we use. Dewalts are decent, but the best quality we have found is Metabo. They last longer and stay together better than the Dewalts. They are 1/2 again the price though...

[Paul]

and a face mask, not just glasses

[AHotRod]

Your right-on Nads!
and saftey is #1.

Glenn

[briggs&strattonChev]

for me it seems the cheaper they get the more they bust apart. I havent gotten hit by the shrapnel yet, but ive come close and ive heard about a guy that got part of one imbedded into his arm

[cadlights]

Mac Tools makes a reversable die grinder that adds more ease
to that job. Almost nothing you can't do with it. Great post.

[chromedRAT]

we use Sait disks in the bronze foundry, but, but possibly of a bit thicker diameter because we cut thick metal with them and fragging blades just pisses ya off. not sure of their price, but we have good luck with Saits.