Welding Sheet Metal

pinchvalve said: I use whatever wire was available and on sale at Lowes. I have never considered size or properties at all. All I do is keep it clean and dry (Thank GRM articles!). Can using a specific wire help me out at all or make the job easier?

...Umm just to clarify. Are you always buying flux core wire? This is the only wire you should be using if you haven't got gas. I can see why you might be frustrated if you're using plain wire.

Gasless welding is not ideal for sheet metal, but it will get the job done. More spatter and you must clean every weld before welding on or near it again.

Cheers

motomoron wrote: Rather than butt welding sheet metal, spend $43 on: An air flanger/punch ...Which is used to make a recessed lip to sit your patch panel on. Welding to this is SO much easier than butt welding panels edge-edge, and you'll introduce less distortion. Also - in addition to flanging you can punch 3/16" holes and plug weld the panel in with those. And, as everyone else has offered, .023 -.025 wire helps and I'd consider Co2 to be mandatory. I use C25 (25% Co2/75% argon) in my machine, but I did a whole car - years of bead - w/ C02 only.

Flanges and plug or spot welds in automotive apps are rust traps, at least in some parts of the country. I only butt weld on automotive body panels.

DILYSI Dave wrote: Using gas and .024" wire will make the job eleventy times easier.

Kenny_McCormic wrote: You can weld sheet metal down to 18 gauge or so with .030 flux core wire, it just takes a lot of skill. Using .023 solid and gas will make it much easier. You are using a #10 shade, right?

What these guys said. If you are welding thinner metal, use a thinner wire.

I don't know the specifics of how to do it properly (I still suck at sheet metal) but I know that some people hammer the weld a bit while it is still warm. Hopefully someone with more skill has given the specifics

When welding thinner stuff than 18 gauge with flux core, just tack around randomly until you have about half an inch between tacks. Leave it at that. Nine times out of ten, this is stronger than whatever metal was spot welded in originally. You will never get a bead worth anything with fluxcore on metal thinner than 18 gauge or so, even doing thick on thin, I know this the hard way. One Yugo strut tower looks like crap, the other looks like a pro did it with limited equipment.

Why not use panel glue no warping

NOHOME wrote: I fit panels with zero gap if at all possible. I never understood the gap thing since all it will do is introduce warping as the bead shrinks when it cools.

In my case (and it's probably me screwing something up) welding in a patch with zero gap means I wind up with the metal bowed up, the metal tends to warp toward the heat source. If I have a gap of around .030 or so and skip around like I mentioned, I don't get the bow. Now, during welding yes I do have to sometines resposition the panels with a small body hammer etc.

I use the flanger on flatter patch panels, I trim away most of the flanged perimeter tho, works for me

Thanks for all the advice. I do use flux core wire, and I am going with butt welds due to the rust issue here in the NE. However, I do not have access to the backside of the weld so those clamps are out of the question. I can secure it with Vice- Grips and magnets pretty accurately, so I think I will be OK. I am not sure the added cost of CO2 ($350 to add the kit and a bottle) is worth it for this project, but something to look for used on Ebay for sure.

ditchdigger wrote: Silicon Bronze welding wire http://www.usaweld.com/023-Silicon-Bronze-Welding-Wire-p/58223.htm Lower melt point, easier to grind, doesn't pull back like steel fillers so it minimizes warping yet unlike brazing, paint and fillers actually stick to it. Perfect for sheet metal repairs. Not cheap though.

I bought a roll of this recently for ~$20 and it works great for sheet metal. Need 100% Argon as the shielding gas - with trimix it splatters like a mug.

$50 a roll? Guess it would be worth if it lived up to claims. Gonna have to look into this.