paint cracking on drip rail seam sealer

[SGTPaul]

Hi All, Hoping someone can help. was sanding out the evercoat finish sand primer on the car yesterday and noted that the pain had chipped off the bottom of the seam sealer at the drip rail. Pushing on it elsewhere in the drip rail channel it kept cracking and popping off. I used SEM single part seam sealer, PPG DP90 and then evercoat finish sand primers on it. I scuffed up the seam sealer pretty good. The seam sealer is pretty spongy not rock hard like the old stuff I removed. It's about 3/16" thick. I noticed when removing the masking tape and paper off the car the evercoat primer was cracking off the paper and tape - looked brittle or unbonded? Anyadvice on this issue would be appreciated. Pic for reference below. Thanks in advance!

 

[snakeoil24]

Why a re you using bonds in the seam area? Your going to need to use adhesion promoter if that's not bondo.

 

[4406bbl]

I would suggest a 2-part seam sealer for that area. Sems or 3m.

 

[eldubb440]

sorry you have an issue to deal with......

this is why I use epoxy primer exclusively........it sticks to everything and everything sticks to it......I use it as a primer, a filler, an adhesion promotor, and a sealer

all in one product Epoxy Primer | SPI

 

[eldubb440]

I would suggest a 2-part seam sealer for that area. Sems or 3m.

agree........ but primer should stick to the SEM stuff, as it would be used in other areas; and honestly, if the primer stuck, no one would ever know what was used

all this stuff (and our time) is way to pricey to just have it ef up

 

[eldubb440]

at this point, I would clean that up and use an adhesion promotor as suggested above.......

something similar to this

 

[zyzzyx]

I had to dig out some of the seam sealer in my gutter on the Passenger side of the car and replaced
it with 3M single stage grey seam sealer in the caulking tube. I let it set up for a couple of weeks and
then shot Evercoat Slick Sand over it. No adhesion problems at all. I sanded through the primer into
the sealer a few times and it feathered nicely. Nothing like your picture shows.

 

[4406bbl]

For me 3m or seems 2 part sealer and spi epoxy works every time. I would dig that stuff out and replace it. Anything still soft will be a problem. 39377 sems can be topcoated in an hour, problem free.

 

[SGTPaul]

Thanks for all the advice and help! Are the 2 part seam sealers stiffer? Thinking the sponginess is a big part of the issue. I used SEM 29382. Or do I have it too thick? PPG DP90 is an epoxy so don't understand why it doesn't stick. Thanks

 

[hunt2elk]

The 2 part seam sealer is a lot tougher than the standard stuff. I forget what brand I have used in the past, but it is specifically for drip rails.

 

[threewood]

Agree on the 2 part SEM. This stuff fills and flows great. I put epoxy on top of mine.

I have the gun if you need it.