I have a '73 challenger. It has the horrible 70's sun roof cut into it. They missed the support. Can this be welded up? I'm a pretty good welder and have all the tools I need. Now I know I'll get a"just put a skin on it!" But that is over 600.00, so if it is possible to weld it that would be worth a shot. Has anyone actually welded one and had it come out ok. Thank you!

Anything is possible when talking sheetmetal replacement. Keep in mind the roof has a curvature to it, so a similarly curved piece will be needed for donor material. Some filler will be needed to block sand out really slick. After priming and painting it will look great. What I don't think you'll like is that once you start driving it, the roof flexes, the sun beats down on it, the filler shrinks, the repaired will show.
If it's just a driver quality car, go for it.

I welded over a sunroof in a Duster, then put a Vinyl top over it. It turned out GREAT!
The trick for me was to use an air powered flange tool. It created a recess in the sunroof plug so that when it was installed from underneath, it sat flush with the rest of the roof. I repeatedly stitch welded until it was fully welded, then primer, filler and plenty of sanding. I may have been able to skip the vinyl top, but I was trying to make the car look as close to original as possible.

Your big issue is obviously gonna be keeping warpage down... It's gonna happen, the metal has no real support so if your Ok with a gallon of filler in the roof go for it... Go slow, tack welds only, tack, then moved 6", tack, move, tack move.... Stop & let it cool completely every time you get back to the starting area.. It'll take allot of time & you'll get some warpage, the gallon of filler is an exaggeration (hopefully LOL)..

Like Dave mentioned it'll probably be visible later..

Like Frankenduster mentioned a vinyl top hides may evils...

Have you considered changing the whole top? AMD is making a roof skin for that car. I bet that some guys here on Moparts have changed them.

X2 on flanging , it will stiffen the roof around the hole and then I'd drop in replacement metal from the top. Trim replacement to drop in tight. like said ,little spot welds 6 inch apart, second trip around the panel put spot next to the first and so on . Go easy grinding welds down to keep heat down. Use quality fillers/primer etc and it shouldn't reveal later. Ideally the skin would be the way to go.

Had the same on my '72 RR. Went with a used skin off a donor '71 Satellite. Spot weld drill and patience will make it look a lot better than trying to fill that darn hole...

600 for the skin is the way to go.
If you are going to go cheap, what would you sell it for?

There was 1 in my 70 RR and I flanged around the opening and cut another piece of a roof into it, been done now for 3-4 years and there isn't any places showing on it so I think it is going to stay. I'm like you and couldn't buy a new roof skin. I had to do all the work on my car my self because I couldn't afford to pay to get it all done. Good Luck on Yours. Ronnie

See if you can cut a roof section out of junk car. At least you will have the curvature correct. Then flange it in like they said. It's worth a shot.

I'm in the same boat. Darn sunroof.

I would use the flanger on roof as well , but i would try the 3m weld-less quarter panel adhesive that way no warp-age. flat sand with 80.
Then use tiger hair filler first and flat sand 80 , then bondo long block sand 80 then 180 and 240 by hand. Then glaze puddy any pin holes. Block again. Use etch primer over bare metal spots light coat.
2k primer 3-4 coats and let it sit in sun (If i had a weak to kill.)
320 block sand again on the long block again and primer again with 2k primer. Then wait one day and block with 400. Clean and prep for paint.
I have done it this way and it takes more time then most like to spend
But i have good results blocking by hand.
This is only if you never done body work some people have there own methods just trying to help .

3m uses a special gun for body panel adhesive.
i have been using panel adhesive sense it hit the market, both 3M and Norton. i have had problems with the bonded seam showing up on more than 1 job.

My Petty blue 72 Roadrunner has a sunroof in it also. I got it for a graduation present in 1981,stupid me?? I like the donor piece with a flange and 3M glue ideal?

Panel adhesive is the best way. You dont have to worry about warpage and its waterproof.

Thanks all, I really aprreciate it! Time to get to work. And if I blow it, I'll buy a skin anyways!