Help With Hardtop Paint Issue

[ccg_ga]

I painted the interior of my hardtop with SEM 39143 Trim Black paint and there is one area that the paint just will not adhere to. When I apply the paint to that area it just immediately slides right down to the lip below the window molding in the photo below and pools.

I prepped the hardtop by first scrubbing it with a 3M 7448 scuff bad that was wet with soap and water (the guy at the local auto body paint store told me to use dish soap and water to clean it). I also scrubbed it with a dry scuff pad then went over the entire top with acetone and let it dry for about 45 minutes before applying the first coat of paint.

I asked the auto body paint store guy about the problem area, and he gave me some lacquer thinner to apply but that didn't do the trick either. There has to be something on the top or embedded in it that is preventing the paint from sticking, but I can't figure out what to do about it.

Maybe use one of the SEM plastic adhesion promoter products on the problem area? Any suggestions or help would be greatly appreciated.

 

[ccg_ga]

Update on this in case anyone else comes across this thread. I was able to get the paint to stick to this area by doing multiple very light coats and then letting it dry for 5 minutes in between coats.

My theory is that a little more paint would adhere between coats, and across multiple coats it built up to the point where the paint stopped sliding down and pooling. It probably took 10 coats to completely cover it, but after it dried you can't tell that it didn't adhere perfectly the first time. Go slow, and do light coats.

Here are a few photos of the finished product. I added a custom headliner as well.

 

[Webfoot]

I painted the interior of my hardtop with SEM 39143 Trim Black paint and there is one area that the paint just will not adhere to. When I apply the paint to that area it just immediately slides right down to the lip below the window molding in the photo below and pools.

I prepped the hardtop by first scrubbing it with a 3M 7448 scuff bad that was wet with soap and water (the guy at the local auto body paint store told me to use dish soap and water to clean it). I also scrubbed it with a dry scuff pad then went over the entire top with acetone and let it dry for about 45 minutes before applying the first coat of paint.

I asked the auto body paint store guy about the problem area, and he gave me some lacquer thinner to apply but that didn't do the trick either. There has to be something on the top or embedded in it that is preventing the paint from sticking, but I can't figure out what to do about it.

Maybe use one of the SEM plastic adhesion promoter products on the problem area? Any suggestions or help would be greatly appreciated.

View attachment 206381

Probably some silicone. It's really difficult to get anything to stick to it. I'm glad you figured out a technique to get some adherence. I used to do a bit of auto upholstery work. What you ended up doing is a trick of the trade. Great job. Looks great.

 

[AndyG]

How do you like the headliner...is there a notable difference in noise?

 

[ccg_ga]

Probably some silicone. It's really difficult to get anything to stick to it. I'm glad you figured out a technique to get some adherence. I used to do a bit of auto upholstery work. What you ended up doing is a trick of the trade. Great job. Looks great.

That makes sense. I scrubbed the entire top with a wet (dish soap & water) 3M 7448 scuff pad, then a dry one and also went over the entire top with acetone before applying the paint. I went up to the local auto paint store and the guy there gave me a little bit of lacquer thinner to apply to the area where the paint wouldn't stick, so I did that also. First coat after the lacquer thinner the paint did same thing. I was about to pull my hair out.

Thanks, I am really happy with the finished product. Appreciate it.

 

[ccg_ga]

How do you like the headliner...is there a notable difference in noise?

As far as aesthetics go I love it. I never liked the plain white on the interior of the top, so the black plus the headliner gives it a really nice feel inside the cab.

I think it makes some noticeable difference in noise. I'm running Swamper TSL SX's so there is plenty of tire whine, but at lower speeds, it does seem like the foam in the headliner helps dampen the noise. I haven't run it at highway speed yet, so we'll see how it sounds on that. The foam under the fabric is 1/2" foam insulation board from Home Depot.

 

[ccg_ga]

I also made a bunch of videos of the entire process. Hopefully I will have some time this weekend to edit those and I will post a link here for anyone that is interested.

 

[AndyG]

As far as aesthetics go I love it. I never liked the plain white on the interior of the top, so the black plus the headliner gives it a really nice feel inside the cab.

I think it makes some noticeable difference in noise. I'm running Swamper TSL SX's so there is plenty of tire whine, but at lower speeds, it does seem like the foam in the headliner helps dampen the noise. I haven't run it at highway speed yet, so we'll see how it sounds on that. The foam under the fabric is 1/2" foam insulation board from Home Depot.

Good post.... What brand headliner was it.

Appreciate the detail that really was a lot of my question ... Does it feel a little bit less like a camper shell..... And you answered that perfectly.

 

[ccg_ga]

Good deal, glad to answer any other questions that you have.

So the fabric came from Sailrite and it is the "Trunkliner Charcoal". It is only $9.95 a yard, and I got 2 yards which was exactly enough to do both panels. It is the exactly charcoal/gray color I wanted and they shipped it the same day I ordered it.

The fabric is thick enough to feel like quality material but not to thick to cause issues on the corners where it needs to be folded. Thankfully my wife is pretty good with upholstery so she helped me with attaching the fabric to the board and folding the corners (in full disclosure...).

https://www.sailrite.com/Trunkliner-Fabric-Heather-Charcoal-54

 

[ccg_ga]

Good post.... What brand headliner was it.

Appreciate the detail that really was a lot of my question ... Does it feel a little bit less like a camper shell..... And you answered that perfectly.

See above, forgot to reply to your comment.

 

[steelhd]

That makes sense. I scrubbed the entire top with a wet (dish soap & water) 3M 7448 scuff pad, then a dry one and also went over the entire top with acetone before applying the paint.

Part of your problem may be that you got your steps out of order. In the body and paint shops I worked at back in the day we would always start with a good detergent and water wash and then use solvent before any abrasive was ever used. (Eastwood lays out the steps here https://garage.eastwood.com/eastwood-chatter/prepping-a-car-for-paint/) The reason is that sanding and scuffing pushes remaining contaminants like silicone, wax, and grease around and into the tiny little valleys in the surface you are trying to create making the contaminants much more difficult to remove. FWIW I dont believe we ever used acetone. Cant remember the brand names but they always used products specifically formulated for paint preparation (Prep Solv, etc) and occasionally lacquer thinner.