Some questions aobut painting this bumper.
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So last week I sanded off the primer that was on the new bumper, then on Sunday I sprayed adhesion promoter and 3 coats of Dupont Epoxy primer/sealer.
It sprayed nice except a few areas that has runs and dust nibs, I sprayed in kinda heavy so I had pinholes in some places.
So today, I sanded off the runs/dust nibs/pinholes with P800, but cut through some small areas and egdes:
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So do you guys think I should spot prime these areas? I really don’t wanna take out the gun and primer again and I’d like it painted by sunday. :blush:
I’ll use SEM’s adhesion promoter and high build primer in can if I need to.And last question:
What grit do you guys use before spraying mettalic basecoat, in this came BMW arctic Silver 309. I’m thinking either 800 or 1000.What do you guys think?
If its just a few little spots I wouldn’t feel too guilty just using some 1k high build. Fill your pinholes with some polyester putty first. I would just finish in 600 with my system, 800 seems so fine but I know some manufacturers recommend it. I don’t really know why the recommendations change so much. If you can fill your little marks with some polyester putty & use a 2k sealer instead of 1k aerosol high build it could make for a better quality job. Either way I wouldn’t worry too much. You know the best way to do it, but if it works for you it works for me. 😉
Thanks for reply Jimmo.
The pinholes sanded nice and flat, so there is no need for polyester putty. They were probably in 2nd or 3rd coat. And about 1/2 inches tops.
Do I need to use adhesion promoter again? I’m thinking yes.
I’m going to home depot later, get a small roller and roll in some 2K highbuild primer over those areas, then sand it nice and flat.:wak :blush:
Yep if you’ve got any remote plastic showing, it will bead up. If there’s not too many area’s showing Just spot the adhesion promoter in. Also if I’ve got any previous base coat showing, I’ll spot it in to. Just to avoid the solvents from messing with it.
And I’ve also found if you have any basecoat showing you’ve likely got small scratches down to the plastic, and it always seems to bead up on me…
At least it does every time I decide “Eh, it’s good enough and don’t need an adhesion promoter”
But if I don’t give a damn it never does it… :blink:
I got a few foam brushes from canadian tire today. Hopefully the urethane solvents wont melt the foam :lol1
RatStang,
the bumper is brand new that came primered, I just rmeoved the primer and sprayed adhesion promoter
and sealer over it.
If I spot in the adhesion promoter, is it o.k if adhesion promoter is sprayed over primer? and is the area gonna be visible or “map” once you spray basecoat?If the areas you have gone through are small I would take some of your adhesion promoter on a towel and just dab the spots of plastic, let flash, spot seal, flash, then basecoat. You shouldn’t nave any problems. When you seal just dust a light coat on your spots then a wetter coat.
I have never used SEM adhesion promoter, that’s the reason I said to dab it with a towel. Some brands will want to lift the finish around the area of plastic. I don’t know if SEM is like that or not. One thing you have to worry about is the plastic that’s exposed getting hairy looking. If you have wet sanded it that shouldn’t be a problem. If the bumper is made of PP+EPDM, PP, or PPO then it stands a better chance of getting hairy. If it’s a more rigid type like ABS you have less to worry about.
ryanbrown999,
thanks for reply.
The bumper is Polypropylene (PP). So now I’ve decided to use the SEM primer in can.Do you think I can use Q-tip instead of a towel to spot in the adhesion promoter?
I will be sandin the area with 400 and then spot primer it.Honestly you probably don’t need to prime. You should be fine wet sanding your spots with 800, spot sealing and painting. Don’t make more work for yourself if you don’t have to.
With that said if you feel better spot priming just spray or dab a little adhesion promoter on your spots with a towel that you would use to wipe it down with and prime. I would think a q-tip would leave cotton behind. I don’t know though as I have never tried it.You might be fine spraying the adhesion promoter on the spot. If the only substrate you have on the bumper is epoxy I can’t imagine it lifting. But, I have never epoxied a bumper or used SEM ap so I couldn’t say for sure. I know that one od duponts adhesion promoters will lift some substrates but not all.
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