Repainting roof of my car…need some advice

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This topic contains 12 replies, has 7 voices, and was last updated by  candace 2 years, 7 months ago.

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    Hi everyone, first time poster. I’ve watched a lot of the videos on youtube and they are great. I’ve seen a lot of contradicting info on my issue so I’m wondering what you all think.

    2 years ago I sanded out a rust spot on my roof and tried to blend into the rest and it didn’t work out so well. Blend job was bad, rust came back, and now the clear even cracked. Attached is the picture if anyone wants to clarify anything. I used just a standard sandable primer on the bare metal and “tried” to feather back. Duplicolor Perfect Match base and Dupont Acrylic Clear.

    Anywho…I’m looking to sell the car later this spring and would like to do a better job on the roof. I’m thinking I may as well just repaint the entire thing so blending isn’t an issue. However, I don’t think that if I did it and the same result happened that the next owner would be very pleased. That leads to my main issue:

    I purchased a bottle of Eastwood Spray Max 2k clear online that’s en route. The contradicting info I speak of is whether this urethane clear is compatible with an acrylic base like Duplicolor Perfect Match. Can anyone shed some light on the situation? It just opens up what feels like a pandora’s box of questions for me:
    – What is the factory clear on the roof?
    -Can I just sand and paint directly on top of the existing paint with Duplicolor? If not, could I just sand and paint with a different type of base?
    -If not, what types of primer can I use? If 2k primer is the only lasting option, then can I use Duplicolor over that?
    -Again, will the 2k clear bond well enough with the acrylic base?

    I’ve read that it can melt the acrylic base, but also read that if I give it ample time to gas off, and go light with my first coats of clear that I can still be safe in the end.

    Side question: I would just get a urethane base if I knew anything about where to purchase and how much it would cost (Toronto area). If it’s in a reasonable ball park I would just get that without question and then it just becomes a question of whether I need primer for my job or not.

    Any help is appreciated. I would like to not make any mistakes this time around lol. Thanks!




    Welcome, I’m not too familiar with any of the products you speak of but if it was me I’d sand the existing paint down to a stable substrate,repair the rust, etch prime the bare metal that’s exposed, prime again with a good 2k primer surfacer ,let dry overnight, block sand with 320 up to 600 , mask of the entire roof , paint complete roof or blend of with a good non generic base coat and then apply a 2k clear coat.



    duplicolor base is the root of your problems i bet…not sure but i think its actually acrylic lacquer..an a very cheap one at that



    I know some jobbers can mix base coat in spray cans. RM has 2 part clear in spray cans if I read their product catalog right. Tuff to pull off that repair with spray cans.

    I wonder if you could wash that paint off with thinners. I bet it is gummy to sand.



    Thanks for the replies. Anybody in Canada or the Toronto area know where I can pick up a higher quality oem matching aerosol?

    Say it is the acrylic lacquer I end up using anyway. I’ve already purchased the 2k clear. Will it still adhere?



    So I managed to find a location and price on a urethane based aerosol at a reasonable price.

    Now the only question is prep work to the original roof. I know I’ll need to sand the rust spot to the metal and prime but is priming necessary for the entire roof?

    What type should I use if so? Thanks



    Not necessary to prime the entire roof. I would remove all of the paint that you previously applied. Not to metal just to original paint to be sure that you dont have any issues from here on. Feather the edges out. Etch prime bare metal. then use a good quality 2k primer/surfacer over the repaired area



    Almost a lesson in how to do it wrong. But fixable.

    First “standard acrylic (or lacquer, if you prefer) primer has virtually no rust prevention qualities at all. Worse, in can absorb moisture and hold it against the metal to cause rust. So an etch primer is necessary first.

    The Duplicolor base coat is just acrylic and this is fine under an acrylic clear (where it is necessary to apply early coats lightly because the thinners content (up to 60%) can attack and soften your base. Full flash off is essential and 2-pack urethane clear will be fine over that base.

    Blending in a clear edge by feathering it just does not work with acylic. It is possible to blend in with blending thinner but not really recommended and certainly not on a big panel like a roof.

    prepare as detailed above and blend out you colour then clear the whole lot.



    Thanks guys for the responses. So what I’m understanding then is if I etch prime the bare metal, I can essentially get away with the dupliciolor base followed by the 2k clear if I let ample time for the base to completely flash off? 7-10 days or so?

    I’ll do what I gotta do but in the interest of cost effectiveness I’m just looking to get a job done that’s good enough.



    If you apply basecoat without first using a primer surfacer you will get rings and bullseyes and likely sand scratches. The purpose of the primer surfacer is to fill in the feather edges and sand scratches. It keeps the basecoat from soaking into the repair. Sand around the area with p320. Apply 2-3 coats of a 2k primer surfacer With 5-10 minutes flash between coats. Let dry overnight. Block sand with 400 up to 600.



    [quote=”geraci89″ post=36961] So what I’m understanding then is if I etch prime the bare metal, I can essentially get away with the dupliciolor base followed by the 2k clear if I let ample time for the base to completely flash off? 7-10 days or so?

    No. Etch prime first, then a sanding primer (as bondobob said). Apply your Duplicolor in light coats, extending each coat a little further than the one before and allowing 10-15 minutes flash between coats, then maybe an hour before clear. If you were to wait 7-10 days you’d need to sand it again and you don’t want that.



    Thanks for the patience in clarifying. I just don’t want to have to do this more than once more! lol I’ll wait till the weather warms up a bit more and then post my step by step and results



    I would sand off all the paint you applied, with 180 then move up to 220, and 320. Because if you paint over it, it’s probably going to keep cracking in the future, and show through your new paint. Prime it all with a 2k primer, and buy some cheap solvent base, like Sherwin Williams, or Besa by Bernardo. Top that with a 2k urethane clear. You’re in Toronto, Napa sells Besa, it’s a great cheapo solvent base. Acrylic finishes do not last in our climate.

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