Thin Gauge welder choice

[JASON123]

Hello,
I am getting ready to start finish welding a chopped 49' Ford I am working on. The sheetmetal is 18 gauge and I am burning through with my mig. I am considering purchasing a tig to weld the sheetmetal with and to also weld some aluminum frames for my motorcycle. I see the Dynasty 200 goes down to 1 amp output and the sync200 goes down to 5 amps. What amperage is ideal for thin gauge? Which machine would you suggest? Money is always a consideration and this is a hobby.

Thanks

[James Kirk]

Try this:

JW Harris "Twenty Gauge" Wire
.030" Cored Welding Wire

No burn through on thin sheet metal!

[Sundown]

What mig do you have?

[JASON123]

I have a Miller DVI that is running on 220 currently.

[bill5674]

hey Jason ,i have been welding 20 gauge with much success. .020 wire my passport and 75/25 mix.Set the machine low and if you can back it up with something to pull the heat away.you might have to use short two or three second welds .I know i have trouble on some inside corners,but on a flat bead it looks great. bill

[JASON123]

Hey Bill thanks..
What is best to back it up with? Copper or aluminum?

[bill5674]

i use either one .though i have some thin copper,i think it was used for roof flashing i find that it sticks to the work .if you can get some aluminium back there that will work too.When i am able to work on the bench i have a couple of 1/2 plate s that work .

[Sundown]

What mig do you have?

I don't want to talk you out of a Dynasty as I love mine, but I don't use it to do auto sheetmetal as a mig is better suited for this work IMO (I use my MM210 and C25). I don't have any time on a DVI but I am thinking that it should be able to do 18ga-22ga without much of a problem if you practice enough. Use .023-.025 wire & C25 gas ... small tack welds spaced as far apart as you can get them from each other until you close up the gaps. Very short stringers (1/4"-1/2") are ok as long as the fitup is very good, ie., no gaps. Take your time as heat buildup will cause the sheet to warp and its hard to get flat again. Hope this helps, it works for me. As Bill mentioned a copper, brass, or even aluminum backup is a good idea if you can get behind what you are doing.

[JASON123]

Thanks so much....

[Iron man]

What type sheilding gas do you use 75% 25% or pure co2? When welding things like patch panels quarters and such I use .024 wire with pure co2 and stitch weld it about every inch or so being careful not to get it too hot.