sheetmetal welding question (pos. a dumb one)

I am about to chop my top and have a question.
Once I cut the top and drop it down do I treat the weld as any other butt weld and start at the top and stitch back and forth?
I have done plenty of butt welds on thick steel but not a butt weld on 18ga sheet metal. I know I can only do sheetmetal an inch at a time, but it just seems like I will go right thru.
I am problably over thinking this but I am hoping to do this right the first time.

I pretty much spot welded it back together. Just doing a couple spots and alternating sides and blow them with are air line to cool them off.

If you are mig welding it - just lower your amps and turn your wire speed down accordingly - make sure that you have plenty of tacks[even over do it a little,maybe] It would help if you have some form of a non ferrious backer such as copper,brass or aluminum, I have used a steel strip as a backer that I tacked inside ,but I also put in interior panels and you couldn't see the strips. And as you said - only stitch a little - at the most , 2 in. to minimize any warping and do it at different locations on the body till you have it all welded up. And if you have a little blow thru - that's what grinders are for. Good luck - just take your time and you'll do just fine.

Touch

Boltbreaker said:

I am about to chop my top and have a question.
Once I cut the top and drop it down do I treat the weld as any other butt weld and start at the top and stitch back and forth?
I have done plenty of butt welds on thick steel but not a butt weld on 18ga sheet metal. I know I can only do sheetmetal an inch at a time, but it just seems like I will go right thru.
I am problably over thinking this but I am hoping to do this right the first time.

Click to expand...

Breaker,
I suggest you practice a lil 1st! It takes touch to keep from burnin' through. It took me a while but I finally became an expert on weldin' up burn through holes!!!

I turn my welder down on the lowest power setting with .24 wire... that has really worked of me. Practice 1st is the best advice I have for ya though... don't practice on u're top chop and avoid those stupid butt weld clamps if possible.

dmw56 said:

I pretty much spot welded it back together. Just doing a couple spots and alternating sides and blow them with are air line to cool them off.

Click to expand...

I use a series of spot welds like DMW says & hardly ever try to run a real line.

BoB

Thanks guys.
I know I can always get good advise from you guys.
I am going to practice a bit and then have at it.

Good luck!

Breaker,
Good luck & remember... u can always put a small piece of copper sheet or a penny behind any burn through hole to weld it back up. I've even taken a 1" strip of the part I removed & welded it behind the area to be welded back together to make it easier to stitch back up & prevent burn throughs.

BoB

If I use copper on the back side, how do I hold it back there? I have heard this method before but never understood how you attach dis-similar metals.
Serious question, I'm not shaq you know?

The copper will not stick to the steel, allowing you to fill a gap, or weld a little hotter than you could without it. (tip: old pennys are real copper, the newer ones are not)

You would have to have someone hold it for you from the inside - and be sure to give them a heavy set of welding gloves with a heat glove inside.

10-4 about the copper ideas and helpers.
I got my door hinge hardware from MACS today. Once I set the doors this weekend I should be able to start laying out the chop.

You could use some Cleos to hold the copper or small pop rivets. Just dont use the gun on the rivets. Just push them in to hold the copper. Or reach through the back window and hold it.

i use a piece of copper plumbing pipe and flatten on end and the bend the remaining tube up, it give you a handle, works great.

fatdog409 said:

i use a piece of copper plumbing pipe and flatten on end and the bend the remaining tube up, it give you a handle, works great.

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great idea.
Thanks.