Hello everyone, I am using chassis saver paint in a hard to reach seam in the roof skin area which is not going to be seen because the weatherstrip reveal molding is covering it. I used chassis saver because epoxy primer is insane in price and I have seen rust come thru it one time. Previously it was just factory seam sealed with the junk gm seam sealer that I always find rust behind it, usually it just goes over the e-coat. As I know chassis saver, por15 types of paints are moisture cure urethane 1k products. It then occurred to me that I could use a urethane 1k seam sealer that it also moisture cure. I have used Loctite PL Max construction adhesive on chassis saver before and it stuck like concrete and dried nice and hard. However I noticed that it is slightly porous when it dries almost like a hard sponge. I found another product called Sikiflex 221 made by Sikkens. This seems to dry not very hard, it almost the same consistency of RTV silicone which made me worry. Thier datasheet says it paintable with 2k acrylic paints and even sandable. Also, it says it takes a full 7 days to completely cure, I’m 4 days in and it’s very rubber like still. Is there any good chance that I could get 2k urethane primer or even a little epoxy primer to stick and not possibly crack down the road. I know I don’t care if the topcoat basecoat/clear cracks in areas that I will never see like under the reveal molding as the chassis saver will prevent the rust anyway on the car. Just as long I don’t get any rust down the road. I don’t want to buy any super expensive 3m intermix dual cartridge seam sealer. Also here are some pics, I went ahead and removed the sikiflex and chassis saver on one side in an attempt to start over. I’m still confused if I should do the other side or stop and think about it.
I would greatly appreciate some advice

Hello everyone, I went back and did a test spot with some upol 2k urethane primer. First I was able to scuff the seam sealer with a red scotch pad. I did notice that I was able to go thru the chassis saver to bare metal in some spots.My prep work was using a knotted wire wheel to strip the paint and scuff the surface. I didn’t use any sandpaper thinking that the wire wheel was enough for the chassis saver to bite into and I wiped it down with acetone. I applied two coats, there was also some solvent pop in the chassis saver which has me worried about putting any more coatings.

I honestly don’t think for these critical visable areas where my expensive ppg basecoat is going there may be a problem. I also used some chassis saver in the pitted areas around my welded on door hinges which I flowed in with a brush I think this may be a better idea for the chassis saver as I can coat this area with some 2k primer to fill the void that the chassis saver missed . I was worried that this was a high stress area near the hinge and duraglass would crack. I did also have a section around the hinge that I cut out and patched in by welding. In this case I used the chassis saver and used the loctite pl max over it. I honestly think I’m just going to strip everything off and just go old school with duraglass over 40 grit scratches. I’m so confused and don’t know what to do. I am going to attach some more pics to show the work so far

Sorry but I am not familiar with Chassis Saver Paint.

Most of us use Epoxy Primer as the first step. You can apply seam sealer over it with no issues, let it set the required time and then move on to your next step.