Welding Thin Metal

Rat Rods Rule

Help Support Rat Rods Rule:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

32Bowtie_Rat

Well-known member
Joined
May 24, 2013
Messages
66
What is the best way to weld thin metal?

I'm getting ready to start some metal work for the interior structure of my 32 Chevy but afraid of over heating & blow out.

Any suggestions on type of wire? Amps I should be using?

Any info or links will help [;)
 
Depends on what machine you have, for the settings. Smaller wire is better, because it takes less amperage to weld with smaller wire. Interior structure, like square tubing, or sheet metal less than 22 gauge? Pulse welding works well for thin metal. Basically spot welds stacked. Move around from spot to spot, so as not to overheat one area. Practice on some similar scrap before you start in on the project. Most modern wire feed welders have a chart for settings, that will get you close, then adjust for your welding style, and specific machine.
 
Boneheads a professional welder, I'm a pro at doing things the wrong way so take my advice lightly. :)

Do you mean you're going to be welding square tube structure to the old sheet metal? Something like that? Tack welds and patience keep the heat down - long welds will warp.

Get some body steel from a 80's car and practice on that. I had to practice a bit to keep from blowing through that stuff. Or take a piece of something that has pinhole rust through and practice filling the holes back in. I got a lot of practice making metal on my rockers.

The thinner the metal, the more important it is to KEEP IT CLEAN. Impurities in the weld area like dirt or rust will cause sudden blow through. Gotta clean the backside too or it will blow when the weld penetrate to it.
 
That's exactly what I'm talking about... Welding the square tubing inside the body. I'm afraid of a blow out. I have a lincolon electric 180 mig welder... I really like it so far & have got lots of use out of it.

I watched an episode on rat rod tv with the essex build & was curious to know why they put a piece of sheet metal on the opposite side of the car body & held it in place with a c clamp when they were welding. What is all that about?
 
A backing plate serves two purposes.

1) Keeps your wire from poking thru, a desirable benefit when filling holes.
2) Serves as a heat-sink, reducing warpage.

Use a dissimilar metal (copper or aluminum) so it doesn't stick to the weldment.

.
 
So if I use a backing plate, thin wire (what size through), low amps & keeping the heat mostly to the thicker metal.... I'm guessing should be okay right?

What about letting my square tubing take the direct heat & letting the puddle overflow so it will tac itself onto the thinner metal rather than applying a direct weld??
 
.023 wire. You have the right idea. Hit the heavier material and let the weld "lap" onto the lighter stuff.

You're only making small tacks, not continuous welds. Finding the correct settings is 95% of the challenge. Like the guys said, destroy some scrap until you find the sweet spot.

.
 
I was all about .023 wire for thin sheet metal until I got the Autoset Miller, now I have a pretty easy time working with the .030 wire even on the thin stuff... But yes I do pulse welds, a few tacks in a row and move on to another area..
 

Latest posts

Back
Top