I remember my dad used to lay a piece of sheet metal behind a hole and pop rivet it in, slather it with bondo and call it good. I have watched a ton of shows and learned over the years that there are better ways of doing this. Cutting a piece to fit and welding the seams so almost no filler is needed was the method I wanted to use.

It seams over the last 15 or 20 years I have forgotten how or possibly lost some of my finesse. While attempting to secure the new panel I had cut out tonight, which did fit quite well to begin with, I was using a 110 mig but was far too impatient and kept burning through. So I got out the oxy acetylene and gave that a shot with no better results. Today I ordered OPG’s part number PAN02K compete seven piece truck pan kit and I’m actually a little concerned that I might not be able to get it in.

Can someone please give me some pointers on the best method(s) for fixing & reattaching new metal? I’m talking about specifics, what type of rod, heat setting, brazing tip sizes, that type of thing…..

I too am a new welder, so I can't give you much advice as I've only been welding a couple weeks. From my experience as a beginner, I think you have your settings on the welder wrong or are welding too slow.

But I am in the process or welding in new floor and trunk pans I've had good luck with .023 dia wire. I'd weld about a half inch then go to another side weld half an inch letting each weld cool before I went back to prevent warpage.

I use a 75/25 gas mix and 1/2" stickout to reduce heat. (this is all using a MIG welder)

For Oxy/Acet. you have to be careful with the heat. You will need a 0 or 00 tip and the smallest copper coated welding rod you can get. It took me lots of practice to learn how to adjust my tip flame. I got it down pat now. Low pressure and small tip. Hopefully this link will help you out. It talks about MIG and OXY/Acet.

Welding sheet metal on cars (http://clubs.hemmings.com/clubsites/chevylist/tech/hammerwelding.htm)

Oh yes and patience. You may have to learn that.

Marty

Thanks for the ideas and for the link, I hate to even admit this but last night I was using galvanized sheet metal. I’m sure that was my biggest problem. I will check my tip size and I’m running about 12 lbs on both bottles (is that to high?) You mentioned “copper coated welding rod” is this copper rod with a special coating or a different metal with a copper coating? -- The rods I have now are gold on the inside, I think they are brass with a white coating.

I picked up a 4’ by 4, sheet of 18 gauge cold rolled steel today to make the new patch panels from. I’m thinking 20 gauge might have been better? 18 is way thicker that I thought

Thanks again and anymore advise will be gratefully accepted

I use 1 psi on both oxy and acetylene. 12 is way too high. Should be below 3 psi. I use an 0 tip. The welding rod I use is R45 Low carbon steel filler rod. I think it is 1/16 inch. This has a copper coating to protect the steel and keep it clean.

I thought that the panels on the old cars were 18 gage. I don't know for sure maybe it is 20. I am using the old fenders for my patching. Same steel, so not too hard to weld together.

The rods you have are for brazing. You don't want that for good welds. You can work the R45 after welding, because you will get some warping and shrinking. A hammer and dolly can fix that in a jiffy. The brass will crack and not fuse together as good.

If you have to weld a butt joint, back it up with a piece of brass. Also, you don't want to try and run a bead on sheetmetal. You weld it by stringing together a series of spot or tack welds. Weld one or two in one location, then move to another part of the panel and weld one or two more, move again, and so on until you tie all the spot welds together.

If possible, when welding in floor panels, try to plan the job so that your joints are joined at the legs of the support structure underneath. You have to cut the spotwelds at those locations anyway when removing the old section of floor panel. Cut the old sheetmetal right over that lip and then use the lip to back up your welds.

You guys are great this is just the info I was looking for!! graemlins/thumbsup.gif
I got a little a head of myself and removed the old pan already. http://members.cox.net/renslove70ss/trunk.htm
I’m fine on the latch side of things but I may have went to deep in the back by the seat. O-well it needed to go one way or another. With the right settings & rod I’ll figure it out.
I really appreciate the help, thanks again

You bet ya. I forgot about that tack weld part. Thanks Randy for adding that.

Good luck Darren

Saw this demo'd at Spring Carlisle. I really thought it did a great job. I was going buy one to do my floors.

http://www.cobratorches.us/

Eastwoods has them but I think you can go direct and get them cheaper. For ~$20 you can get the video and if you buy the torch, it's credited towards the price. If you want to know how to weld sheet metal, this video will teach you.

About 20 years ago I was quite proficient at it. With the advise I have received here things are working much better now.
thanks again

Originally posted by 70 nialator:
Thanks for the ideas and for the link, I hate to even admit this but last night I was using galvanized sheet metal. I’m sure that was my biggest problem. Just surfing posts,
Please correct me if Iam wrong but welding galvanized metals is a bad thing.I was told, perhase incorrectly, that when you weld galvanized material it gives off a nice toxic gas. Is this true? If so, well a reduction in lung capacity worth a Chevelle anytime.

John C.
Pensacola FL
65 wagon project.

Just FYI . I have purchased a ton of parts from OPG and never had a problem until now. I’m not bagging on OPG they are taking it back and seamed quite concerned about what I described as far as the condition of the piece.

The PAN02K is made from about 22 or 24 gauge steel (about the same consistency as a heavy aluminum foil) the drain plugs are fake and not separate pieces & the tank brackets are NOT welded on as described on the website. This coupled with it did not go back as far as I needed and the poor packaging, severe damage caused while shipping has me a little upset…..