What to do with this?

[Charger_Croatia]

Roof on my car looks good but than I noticed small cracks under primer on one position(car came like that). After removing primer I found some of bondo and I removed all of it.
Question: what will be the best to do with this (see picture)?
I'm looking for the best way to fix this. The easiest would be to put new bondo but I'm afraid to have it cracked again. Next would be to do spot welds to fill holes and than thin layer of bondo.
Maybe the best but the hardest would be to cut this and use small patch (dimension is 1.5'' x 4'') but since I'm not expert I don't know how it will look at the end.

[69 OUR/TEA]

Hello Charger_Croatia,it looks to me that this has already been spot blasted,the inside the pits are to clean with just a little rust evident.There is a product called DX 579,from PPG,it is an acid that you put on to dissolve rust.Use a little size wire brush,put some of this on,let it sit for about 30-40 seconds then start scrubbing that area trying to get deep into those pits,you will see the rust dissolve and come out.Clean area with a prepsol solvent.If you were to try and zap those holes with a mig weld,chances are you are going to blow thru if you are not an experienced welder,so for such a small spot,there is a product called All-Metal,it is a type of body filler but actually contains metal in it .Use this to swipe in those two small holes and fill in the pits first then use whatever plastic bodyfiller you are comfortable with.I personally use Rage or Rage Gold.If the headliner is out of the car check the back side of this problem area,if there is rust on the back side clean with same product,and put an etch primer or epoxy primer to seal it.

[4402tuff4u]

I would mig weld them as stated above. My Charger was full of areas like that on the roof since it's whole life it had a vinyl top with and A/C unit - so imagine and picture the condensation going on beneath the vinyl top. The car had absolutely no rust but the roof was another story. I learned to mig weld as soon as I got the Charger and I mig welded shut all the small holes myself. My body guy said to me that that is the only way to prevent moisture from entering the steel! He even went as far as welding up - mig welding all & any hole that he found on the Charger's skin. I had to mark for him all the emblems and accessory holes before he started. You set the mig settings to the lowest setting with a high speed wire feed so that you apply lots of filler metal as soon as you make the arc. Some holes will definitely grow!! They did on me and I was freaking out, but my body guy said that's normal. You stop and move to another location on the roof and let it cool down before returning. It will look sloppy when you are done with little mounds of weld all over the place, but once to grind it down it will look pretty good. My body guy said you can also hammer it to shrink the metal and flatten the weld before grinding. He also cut some patches out, curved them to the proper contour and welded them in. I was not brave enough to do that. From your photo, you problem is way less than what I had.

If you decide to mig weld them, makesure you protect the interior - cover it, protect/cover the glass VERY IMPORTANT! and you must remove the liner. Cover everything as if you were painting. The mig splatter is very damaging!!!

[Charger_Croatia]

It seems that there is no need for one piece patch, from what I understood above.
I think I'll leave this for the last after I got more experience on welding. I have enough places (hidden) where I can practice MIG welding.
What is interesting, this is the only bad spot on whole roof, the rest is fine.

4402tuff4u, thanks for advice. Most of the interior is out, so is headliner. I shall protect the rest as suggested.

[69fourspd]

I agree with 4402tuff4u.  I would weld them shut, but you may want to think of putting a piece of copper beneath the holes.  This should help fill them and transfer heat better.  Good luck.

[Charger_Croatia]

Thanky you guys. I'll post pictures after finish this.

[4402tuff4u]

I agree with 4402tuff4u.  I would weld them shut, but you may want to think of putting a piece of copper beneath the holes.  This should help fill them and transfer heat better.  Good luck.

That's true about the copper plate that I forgot to mention! Also, if you hammer the welds to flatten them down have a dolly against the inside hammer location - that's common sense, however for someone not familiar with this process it might just slip by and you will then have other problems. Show us your progress, good luck.

[Silver R/T]

I would weld up holes and go from there

[is_it_EVER_done?]

If you have a mig, definitely weld them. If you don't have a mig, use JB weld and it will be just as good and will never crack.