as longs as its the same thickness, you wont see a big difference in weight. Also you can use a mig to weld stainless steel, you dont have to have a tig. Tig is nicer because you wont get splatter and its a bit easier to control your pool. With mig you will get splatter and controlling your pool is a bit more tricky because it just doesnt flow well. As long as you get spatter block and use it well, you will be fine. I weld stainless at work all the time and use a mig if i have to, no problems just make sure you are using 308 stainless wire
Stainless is around 5 or 6% heavier than mild steel. I forget the exact number. Mig welding stainless is a process alot of production companies use. But I wouldnt recommend it for someone that doesnt have knowledge of how to setup your machine. You can make a much worse mess than running Er-70 wire.
not to jack but if repairing a set of stainless steel headers would it be better/easier to use mild steel tubing or stainless steel tubing and a mig? i have to replace the u bend on the bottom side of an slp header and was wondering what j bend the get.
Calculate the total volume or area you're using of material and use density to calculate weight. Depending on what grade material you're using, the density will vary slightly. Generally speaking mild steel is ~7.85 g/cm^3, 304 is ~8 g/cm^3.
The weight should come out to about 1.875% difference if you calculated it.