Topic: Tips for welding sheet metal?

[NorCalToy]

Does anyone have any advice on welding sheet metal? Im on my 2nd bed bob and its a pain in the ass to weld the bed back up without burning through it.

Im basically tacking it in one spot and moving up 6" or so and tacking again and so on. with the welder on the lowest setting and a slower wire speed.

Will running a different (thinner) wire help? Wire speed?

[Ironloki]

how big is the welder being used? I have a 140 at my work that works well, find some scrap steel if ya can, make a small gap between the two, and practice.. i used .030 wire, and had the machine below halfway for power output. with the wire speed adjusted accordingly. oh and if ya can flop the bad on its side, and use gravity to your advantage, prolly wouldnt be a bad idea either. good luck!!

[THK Matt]

Lincoln 220v is what he said on the shoutbox.

[Toymin8r]

Run .025 wire on your welders lowest setting and slow the speed down really slow.    The only way to buttweld sheetmetal it to to what you are doing.  Spot welds every couple of inches. 

check out my build thread I just got done bobbing a bed.  http://board.marlincrawler.com/index.php?topic=68583.120  Starts on post #141

[TacoRunner]

Something I  learned the hard way, was simply to make sure the metal is as clean as it can be, nothing will screw up  a weld like contamination.

[superyota]

Havn't had a chance to try it yet, but i had a buddy tell me to put a piece of aluminum behind it.  supposed to stop it from blowing through and help it puddle up .  I've always just stitched it, about a 1/2 inch at a time.  working back and forth to help keep it cool.

[yota4x4sc]

basically u just need control of the welder..and runnin .023 wire will hwlp out a lot...just a bunch of tacks..and i dont run the welder on the lowest setting because u want it to penetrate the metal when u  do  a quick tack... i go like 3 or 4 settings on the volts up, thats on a lincolin 175 mig 

[Peterbuilt84]

If you can get a hold of a 110 mig to use that will probably work best. I used a lincoln sp100 when I made half doors and it worked pretty well.

[NorCalToy [OP]]

Iv got a Lincoln 3200 Weldpak HD

Its a 110v wirefeed and im running .030 right now. I may try picking up a roll of thinner wire. Im not using the gas hookup right now, only electric and I had read people saying dont use flux core for thinner sheet metal because it burns hotter...

[junya92toy]

Run 023 wire 75-25 gas, vert down and If you can use a copper bar on the back side of the weld

[Snowtoy]

Iv got a Lincoln 3200 Weldpak HD

Its a 110v wirefeed and im running .030 right now. I may try picking up a roll of thinner wire. Im not using the gas hookup right now, only electric and I had read people saying dont use flux core for thinner sheet metal because it burns hotter...

I have built 1/2 doors and repaired body panels with the same set-up you have, you just have to be patient and bounce around with your spot (stitch) welding.  .025 flux core wire will help out a little with the burn through, but you still have to stitch weld it.

[Peterbuilt84]

I'd definitely use gas. I started with flux core and that sucked, then used 75-25 with I think .030 and it worked pretty well. Thinner wire would probably help too.

[yota4x4sc]

the gas is very key if u want clean welds..  25 75  argon  co2 mixd gas

[2manytoys]

junya92toy nailed it.

.023 solid wire and mixed gas. Runs a lot cooler and cleaner than flux core. Also Co2 gas runs hotter than mixed gas and has more spatter.

The copper bar helps if you can do it. You still have to tack and stitch, and jump around to keep from warping it. Hammer and dolly helps too.

Like tacorunner said. It's gotta be clean. Contamination makes it difficult to control your weld and kills consistancy.

Be careful when you grind it after welding. You can overheat and warp the steel that way too.

[86moneypit]

Ive done some sheet metal work lately some half doors and my brothers bobed bed. I used miller 220V with .30 wire and 75 25 gas. for the bed i cut a splice from bobed part to put behind the two as a gusset and a couple self tappers. It worked great gives something to back up your spot welds. Just jump around alot its not to bad. The splice is the trick its made it so easy. 

[JZ]

I run .035 wire(it was free)and 75 25 mixed gas, just take your time and it will come out nice. make sure you your two pieces are straight as possible with out gaps.

[NorCalToy [OP]]

Both bobs iv done the cuts were far from perfect. which makes it difficult to line them up well.

But i was able to finish the bob up with the 110 lincoln .030 wire wi/out gas. Im not sure why it was easier on the 2nd gen bed than my 3rd gen bed but i could almost lay a bead on the sheetmetal. Had very few problems burning through this time

[zippo]

because you are getting better at welding?

[joshcraig09]

i am thinking of running my tig rig with the pulse i have welded some really thin sheet metal with it... just havent bobbed my bed yet... that is my plans any way... also i have used a bar of carbor for a backing plate that helps but prolly hard to get it in there and match the contour of the bed....

[NorCalToy [OP]]

because you are getting better at welding?

its possible, but im not sure because i havent even used the mig for at lesat a couple months since the other day when i finished the bob

[woodfella]

Go get a 1in copper pipe coupler. Smash it half way with a hammer. Grab that smashed part with some vice grips. Smash it the other dirrection so it ends up looking like a T with the vice grips holding onto the downward facing leg. Hold it up to the backside of the weld as your going. End thread

[NorCalToy [OP]]

That would work fine on 1rst and 2nd gen beds, but itd be difficult to use on 3rd gen beds because the inner wall of the bed inst removable

[miks85yota]

i use an OLD miller welder with 0.30 wire that'll weld anything from sheetmetal to 2" steel plate with gas and as long as u just keep the heat down and take ur time and let ur stitches cool every so often, u should be just fine.just my .02

[Sparkplug]

I just did a bob, didnt get pics, and now its got filler over it to make it look smooth, But, I welded the whole thing with my hobart 210, 220v welder, on setting 1, with .030 flux, no gas. I just stitch welded it, yes it was hard to do, but not impossible.

[theslayer85]

A tig welder also does not spread the heat nearly as bad.  It is a little tricker to weld with, well more getting used to it and learning it.  But tig welders are expensive, and not everyone has one just laying around.  I cut my fenders out and ended up warping the sheet metal a little.  the copper is a good backer for your gaps, the weld will not stick.  As everyone else has said practice, patience and space the welds.  The reason my fenders warped was because I didn't let my small stiches cool enough before going back and adding the next stich.  The side that ended up looking the best was because we couldn't get the welder to work right and could only get small tacks rather than a continuous bead.  Keeping the heat down is the key.  thiner wire and mixed gas really helps. 

[toyota41180]

I welded a bracket on the bottom of a hood and i used a wet rag on the top of the hood to keep the heat down and not burn a hole or melt the paint off and work for me that is just my