butt welding on body lines

M

mblommel

True Classic
I have a peculiar rust are on the front right fender. Just the top part of the fender at the seam is rusted:

5441683109_766c8a22ff_z.jpg


I have a good patch panel on the way from Matt at Midwest. I was wondering if it is a good idea butt weld it in at the body line. I'm trying to minimize the repair area as much as possible. I've done some research on the internet about butt welding patch panels with the seam on the body/character line, but haven't come up with much. Any advice would be most appreciated.
 
Mike, I'm no pro but...

I've dabbled a bit and watched a lot...

I think I woulda bent my own replacement piece but since you have one coming...

You just need to trim it with about a 1/16th of an inch gap... I'd tack it down along the inner fender well first to hold it in place and then start on the ends with ONE tack.

PATIENCE is the key... then allow to cool between a couple more tacks, swinging from one end to the other. COOL again and jump back and forth with about one inch spacing between tacks. Then fill in between allowing time to COOL.

I think this is where HAMMER-WELDING the tacks might come into play here but it looks like a difficult thing on the corner line.

I'd have no trouble grinding the welds and then using a bit of Bondo. I would probably take a lot of time to do this also... but the area is really pretty firm and not prone to flexing... so you should be OK.
 
I was thinking along the same lines

Yea, I was thinking I could have made my own patch panel for the top of the fender. But... after looking at closer I figured $50 for a partial fender wasn't so bad. The X may have a lot of "flat" areas in it's styling, but most of the lines are all subtle curves.

I'm fairly comfortable with welding sheet metal. Mostly I was just wondering if I should seam the patch at the body line or not. After more googling it seems that most say to stay away from the body lines with the patch seam, so I guess I'll extend the patch down the vertical portion of the fender an inch or two.

I'll update with photos as I progress.

Thanks,
 
I'm no welder but...

I think the going theory on welding body panels is to do it in small sections to minimize warping. One stitch will cause alot of heat and warp the metal. Little 1-2" runs spaced apart and doing fill in welds after things cool down helps with the warping.
 
This is what I've heard too...

Stitching or stitch welding, skipping portions so that you get less warping.
 
Ok...

As a person who has rebuilt the front end of a 128 from flat steel, here is what you want to do.

Do not even consider running a bead on this, it will warp the metal.

Instead do a number of spot welds, one at a time and at least a couple inches from each other. Overlap each spot by just a bit and the finished product should look like a bunch of dimes just overlapping each other.

Make sure to get penetration as you will be grinding off a good amount of material as well.

Good luck!

Eric
 
I'm not sure you guys are understanding what I'm asking.:hmm:

I'm familiar with butt-welding sheet metal patch panels on car bodies. I understand that I need to make a series of small tack welds to minimize warpage. I understand you can't run long beads. I've done this sort of work before. I appreciate the advice, but trust me you are preaching to the choir on technique. :grin:

What I DON"T know is if it is advantageous to place the seam of a patch panel right on the body line of the fender. Based on what research I've done it looks like it is a bad idea, but I'm not 100% certain. So if anyone has placed the seam of a butt weld patch on a body/character line in the past if you could lend me any advice for or against I would certainly appreciate it.
:thumbsup:
 
I heard ya... and didn't mean to concentrate...

... on the stitch weld itself so much...

As far as stitching on the body line goes versus a flat portion of the panel... I THINK that the issue is the strength and the possibility of grinding through the weld that MAY be the problem. Not necessarily warping.

I said... that I THOUGHT that since the area here does NOT see any real stresses or flexing... that strength here would NOT be an issue... and in fact, grinding to flatten or smooth would/should actually be easier than a flat panel! I also thing the tendancy to warp would be less!

Here is the bottom line, IMHO... Try it... as you have another panel section coming or available... If you can't weld this to your satisfaction, then cut it all out and weld in the new donor panel on the flats.

Good luck... we'll all be sitting here waiting! HA!
 
I would stay clear of the body lines. It is tempting to use body lines because they are very clear markers as to where to cut, but you are very likely to collapse the body line some when you weld it together. As me how I learned this. :(

Cut in flattish open spaces and be careful.
 
I agree

Definitely don't do it along the crease, the metal is stretched at this point and is thinner and will burn through really easily. It's not the best metal to work with to start with and if you are welding in a used part both will be a challenge to work with.
Cut back at least an inch away from the fold, and follow Eric's advice with the spot welds and it should turn out great!
Cheers,

G
 
Thanks!

I appreciate the advice guys. I will give the body line about 1" clearance. And I will post pics as soon as I have some progress to report.
 
patch panel

OK, so I bought a partial fender from Midwest Bayless to fix my little rust issue on the fender.

Basically a pretty clean fender minus the rocker section:
5466288735_55ae9b93f0_z.jpg


But.... Even good replacement Fiat fenders have rust and bondo!
5466893720_466bf3e5a3_z.jpg


And unfortunately it was right in the section I need to use as a patch. The folks at Midwest are taking care of me, so it's all good. The partial fender was only $50 so not so bad anyway.

Luckily the X1/9 fender maintains a constant cross section most of the way down. I was able to cut a butt weld repair patch from farther down the fender. Heres the result after the first round of tack welds have been ground down:
5466894238_6ff3991e74_z.jpg


Now I just need to fill in the rest of the seam with more tacks and hammer it smooth. A little metal finishing and it should be a good patch. On the plus side the fender has a handy pinstripe below the body line that I will use as the seam when I patch the existing fender on the car.

Thanks for looking.
 
Not good, consider all alternatives

It is hard to do major rust repair on a car that you can replace for so little money. Just my opinion.
Bob T.
 
Bob,

I can understand where you are coming from, but only from a purely monetary point of view. Since I have the tools and expertise, a rusty fender doesn't make me consider junking an otherwise pretty good '74 with solo competition history.

Not all of us can live in California where perfect rust-free X's litter the streets!:p
 
My '81 had rust in that same spot (PS though). It was probably a replacement fender as that side had collision damage repaired at some point (1989). Bit of a weird place to rust, isn't it?
 
Good Point Mike

Mike,
The challenge and the process of working on one's car is certainly much of the allure. If this were not the case most of us would do something else, so your point is well taken.
Bob
ps, I wish the streets were littered with X's, as I too am looking for a '74 to build ( no smog testing required)
 
For those interested I got the patch panel fitting in pretty nicely and put in the first round of tack welds tonight:

5504627956_dfe6d732b6_z.jpg


The fit is pretty good. I will have some metal work to do, but overall I think it will be a pretty nice repair when complete.
 
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