Welder question

[dfl701]

I need some help real quick. Theres a Lincoln SP100 mig welder on Craigslist for sale right now. I gotta call the guy tonight but he is wanting $100 for it. He says the torch may need to be replaced. So my question is...
Should I look into it if I can get the price down?
How much would a new torch be and whats he talking about? im a complete noob in welding stuff.
I have an Arc welder for heavy stuff and I just want to use this for sheetmetal and lighter stuff. Thanks guys

 

[dfl701]

i called and he said i could put the money down and try it out for a few days. said he doesnt think anything is wrong with it because its been sitting for a while.

 

[4X4HIGH]

I'm not the most knowledgable on welders but a mig isn't really good for sheet metal if you don't want it to warp all to hell. A tig is perfect for sheet metal and a mig is better suited for .125"-.500" depending on the machine you get. Pretty sure though that the welder in question is only good to probably .1875" (3/16"). You should PM Rene (trustyk5)

 

[dfl701]

I forgot all about PMing Rene. Thanks

 

[tRustyK5]

Sheet metal will warp no matter what you use. It's more about technique than equipment. TIG is a wonderful process, but usually puts even more heat into the material than MIG does.

A small MIG machine is great for patch panels, rust repair and smaller projects where the material isn't over 3/16" thick. Having a stick welder for larger stuff...it sounds like the MIG will compliment it.

For welding sheet metal, have a good look at how the factory put these trucks together. All the joints are overlaps with spots welds holding it together, the rest is seam sealer. If you're patching in a panel and you have to make a "butt joint", get the fit up good, then limit the welding at that butt joint to a full penetration tack every 1-2". Much more welding than that and it'll warp like crazy.

It'd be really nice if steel didn't distort after welding, but until they invent room temp welding we just have to try to understand it well enough to predict, and work with, the inevitable.

Rene

 

[dfl701]

thanks Rene. the guy sold it another me, grrrr. so im still on the hunt.
so what would be the best way to weld i some patch panels on the floor? im guessing like factory. let them overlap? im new to sheetmetal and welding and i spend lots of time searching this stuff, but its not like talkin to an expert

 

[tRustyK5]

Well, a floor pan situation warping isn't much of an issue as it's not really cosmetic like the outer body is. I like to fully weld floor patches, just keep moving from spot to spot adding a small stitch or tack weld until it's fully welded, then clean with the grinder. Overlapped patches can be a problem on a floor...moisture and debris can get between where it is overlapped and cause you to have to repair it again later.

Either way, a coat of seam seal over the welded areas is a good plan.

Rene

 

[dfl701]

ok awesome. just wanted to make sure i get it right. im on the hunt for another welder now. Thanks!

 

[dhcomp]

As much as its not necessarily for thinner sheet metal, it will work on everything but REALLY thin stuff.

Also, i would never pass up a $100 deal on a miller or lincoln or other name brand wire feed welder. I'd be all over a $100 MIG!

 

[dfl701]

As much as its not necessarily for thinner sheet metal, it will work on everything but REALLY thin stuff.

Also, i would never pass up a $100 deal on a miller or lincoln or other name brand wire feed welder. I'd be all over a $100 MIG!

yea i was! he worked nights and was suppose to call me. well he had to go into work and said call me tomorrow. ok i told him i wanted it! i call him the next morning and its gone.
oh well im on the lookout again