Old Tyme Body Work

Here's hoping there's a couple of old body men, or master welders on the forum list. My Mig crapped out with my car 90% done. It is beyond repair, and I am not going to buy another. I still have half a quarter panel to replace. Should I use mild steel rod with my acetylene rig, or should I braze with brass rod? I know I have opened up old body work that had been done both ways.

Subscribed to see what the responses are. A lost art....

JW

If you're used to mig welding, I'd buy a used one, finish the job, and dump it. I don't know about you, but once I get over a learning curve, I don't feel like starting a new one. Just my 2 cents.

If you must braze it, use brass rod.

All Gas weld need flux. The flux on the back of the panel will cause the panel to rust pretty quick unless coated from the back. One reason you always see old body work bubble. Also the first coat of filler on seams should always be a waterproof fiber strand. Very important to seal the seam. Bondo / plastic won't do that. That is why all seams on cars they used lead unless under a vinyl top. Vinyl top cars are always rusted at the seams and below when the top is shot. the filler they used was cheaper then lead.

As a professional welder for 25 + years and having restored my share of MoPars....
Brazing will get the job done, with that said I personally would not finish the car with it because of the above results are true.

go find or borrow a small mig welder and finish the job. I’m assuming you were running e70s with 75/25 or straight carbon dioxide. There is a lot of truth to the “old ways.” Of doing stuff.... there is a real reason it’s “the old ways.”
And how dare you not share some pics! Lol!

I agree with the comments above. I used to use oxy/acetylene and then once I got mig with gas there is no way I would revert to the old way. Borrow, rent or own short term a mig setup to finish your job.

You will have to have good heat control to prevent warpage if you braze. go Find a MIG machine.

Used MIGs around here are the same price as new .

I would rent or borrow a mig to finish the job.
There's no way that I would use an oxy/acetylene torch to finish the job, there will be way too much warpage.
That is of course, you can't get to the back side of the panel and immediately and hammer and dolly the weld zone every 1/2'' or so which is also known as ''hammer welding''.
When you ''hammer weld'' you are actually relieving the stresses caused by warpage and making the weld more solid as well.......think of power forging and how it works to get a mental picture.
I would recommend against using a brass rod on thin mild steel, especially an external body panel.
How brazing works is almost like glue, it is joining two dissimilar metals together by when the torch heats the metal it expands and the brass flows into the pores and when it cools, it locks the two metals together. (kind of like velcro)
Unless it is done perfectly, it is quite weak and will still warp the sheet metal considerably.
And to top it all off, I have never seen a panel that was brazed on last long term because the use of dissimilar metals won't allow expansion and contraction to be the same at the ''weld area'' and any filler or paint will crack and peel off. And it's not a strong system either because of the tensile strength of mild steel is more than double than that of brass.
It was used a lot in the '60s and '70s before mig welding was popular in body shops.
It was fast and easy, and not many people were caring about the strength of the repair, as long as it held and lasted for a year or so. And then they would trowel on the bondo to fill in the warped panels that were as wavy as the Pacific ocean and call it done.

This is my 2 cents worth, and BTW, I am a journeyman welder that has seen a lot of cars over the years in the junkyards crashed, rusty, or whatever, and this is how I base my claims.

Glue is another alternative . Body adhesive like is used in modern auto assembly .

MIG it!