Help wanted for rear fender repair, - Getting closer. Need welding advice on reattaching Options

[_stickykitty79_]

I used this tool a lot to get the right spacing and curves. Compare the good side to what you are working on.
https://www.amazon.com/Big-Horn-19062-Plast...C169&sr=8-9

we use these on our clay models for automotive design, works well, good reminder for me to pick one up for my resto also

[seanpaulmc]

I used this tool a lot to get the right spacing and curves. Compare the good side to what you are working on.
https://www.amazon.com/Big-Horn-19062-Plast...C169&sr=8-9

Thanks, Bob. This tool was super helpful with my CAD designs. I picked it up shortly after seeing you post about in your build but it’s taken me a while to get to it.







The fit on the hammer formed patch seems pretty good. I’m pleased to move forward with it.

[seanpaulmc]

And like Bob said, take measurements from the good side and use on the bad side, so I did some additional CAD work today in preparation for the future fender grafting.

[Montreal914]

Looking good! (IMG:style_emoticons/default/popcorn[1].gif)

[930cabman]

I am also in this boat with the drivers rear quarter. Looking good, I would recommend taking your time to get things correct. Theres alot coming together in this location

[friethmiller]

Sean, what kind of welder are you using? It looks like it might be flux core. I know the metal is thin but try bumping up your heat just a bit to get better penetration.

[volksaddict]

CAD = Cardboard Aided Design? (IMG:style_emoticons/default/biggrin.gif)
Just kidding, your attention to detail is great!

[seanpaulmc]

Sean, what kind of welder are you using? It looks like it might be flux core. I know the metal is thin but try bumping up your heat just a bit to get better penetration.

Fred, you are too right, but it’s not welder, it’s the ‘welder’. User error for sure!
To confirm your astute observation here is what the back of this patch looks like now that the donor has been disassembled…



I haven’t been welding in a few months and was having difficulty getting it right. After blowing a few holes in it I turned it down and wound up with the snot seen in the first picture.

I’m grateful for your feedback and advice on how to make it better. There’s plenty of practice ahead in repairing the donor pieces. I’ll take all the feedback I can get.

Cheers,
Sean

[friethmiller]

Yep, I could say the same thing about some of my work from my last build. Hell, you can see this in a few of the pics I posted on this thread. I’ve learned to use a metal gauge to verify thickness, setup the welder based on its recommendations, and then make small adjustments till I get the desired results. Also, the gap between the metal is very important. You can’t expect good penetration if there is not a gap. Things shift and expand once you start tacking the patch in place, too. I use a cutting blade to re-establish that gap when that happens - before continuing on. Keep at it. Keep trying to get better, learn from others, use YouTube, etc.

[seanpaulmc]

friethmiller[/s]' date='Jan 4 2026, 08:43 PM' post='3239523']
Yep, I could say the same thing about some of my work from my last build. Hell, you can see this in a few of the pics I posted on this thread. I’ve learned to use a metal gauge to verify thickness, setup the welder based on its recommendations, and then make small adjustments till I get the desired results. Also, the gap between the metal is very important. You can’t expect good penetration if there is not a gap. Things shift and expand once you start tacking the patch in place, too. I use a cutting blade to re-establish that gap when that happens - before continuing on. Keep at it. Keep trying to get better, learn from others, use YouTube, etc.

My penance practice has been the repair of this donor quarter / tail section.



Thanks again for the advice.

[friethmiller]

Thanks again for the advice.

You bet! I enjoy watching your progress. (IMG:style_emoticons/default/beerchug.gif)

[seanpaulmc]

Progress has been made. Mistakes have also been made. Would like your advice before I try putting this quarter panel back on.

See pictures.
1. Should I try to weld both vertical seams with the panel in place on the car? Or,
2. Should I weld and dress the patch off the car before attempting to reattach the quarter panel?





With option 2 I realize I’ll have to have a really good finish on the patch in order to to use the panel alignment clamps.

Thanks in advance for your feedback.

[Montreal914]

So, I am not a pro, far from it... (IMG:style_emoticons/default/rolleyes.gif)

If I was in this situation, I would attache the slim piece to the rear piece on a bench. I would clamp a copper block as backing and for local flatness (colinear) joint. Obviously, gazillions of one clic spot welds with full cooling after each weld.

Now, I am sure the real pros will give you the good advices.

Good luck! (IMG:style_emoticons/default/smash.gif)

[friethmiller]

I’ve done this sorta thing before. Either option if fine. If it were me, I’d only tack the small sliver on the patch and then tack the patch to the rear quarter. It’s a matter of heat distribution to me. Once the patch is tacked to the rest of the fender, you now have a greater area to take the heat. Another thing I’d recommend for a fender would be to go slowly and allow the welds to cool without a bunch of compressed air. Rapid cooling will cause the butt weld to pull inward. It’s not the end of the world if this happens where you can hammer/dolly it back but there can be places where access is limited and it’ll take addition work/tools to pull out these lows. Think “slow finesse” not “brute force” here and you have a shot at good results. Good luck!