Why does some spray paint scratch so easily?

Discussion in 'Color is everything!' started by TABuickMike, Mar 24, 2011.

  1. TABuickMike

    TABuickMike Michael Tomaszewski Jr

    I'm working on a project for an engineering fraternity I'm part of where I'm building a barbecue out of a 55 gal drum. A requirement is that it has to be red, so I picked up some red BBQ paint (http://www.krylon.com/products/bbq_stove_paints/) for the high temp ratings (up to 1200 intermittently) so that it (hopefully) wouldn't burn off. I have everything all painted up and I just realized tonight that even though its sat for a week, I can scratch the paint off down to bare metal with just my fingernail. What gives? If I can take it off with my nail, this thing has no hope of retaining any paint during normal use (it goes camping, to social events, official events, you name it). I've always had this problem from Krylon paints and is why I normally use Rustoleum, but I needed paint that withstands high temperatures. I thought about a Rustoleum matte clear coat to put on top, but I figure that would yellow from the heat.

    Is there anything I can do to make the paint stick, or at least be a little more durable?
  2. cstanley-gs

    cstanley-gs Silver Mist

    nothing for the paint to bite into..

    What grit sand paper did you use to prep the drum?
    What primer did you use?

    Or a dirty oily surface? Did you wipe it down before painting? With what?

    Im no expert painter.. but just throwing out idea
  3. cstanley-gs

    cstanley-gs Silver Mist

    Also, spray can paint is a very thin coat.. no substance to one or two coats.
  4. rack-attack

    rack-attack Well-Known Member

    Many high temp paints need to be heat cycled to cure. Before they are cured they remain soft
  5. cstanley-gs

    cstanley-gs Silver Mist

    Oo good point... throw on a rack of ribs!
  6. TABuickMike

    TABuickMike Michael Tomaszewski Jr

    First I hit everything with red scotch-brite then washed it with soap and water and scrubbed it all down. Then after I blew out all of the cracks and welds with air, it sat in the sun for a day to dry. Then before painting I sprayed it down with lacquer thinner, let it dry, and painted. I was thinking that maybe it needs some heat to cure it, so I'm going to test a spot with a heat gun tomorrow to see how it does. :moonu:
  7. pglade

    pglade Well-Known Member

    One thing...lacquer thinner....not a good pre-paint cleaner as it can leave a film on the surface. A good wax and grease remover used according to instructions is the way to go. Wax and grease removers don't "remove" the impurities as much as they merely lift them from the pores, etc so you can THEN remove them with another towel by wiping the surface while it's still wet.

    With thinner, etc sprayed on there and left to dry you may have just lifted more impurities to the surface where they remained once the thinner evaporated.

    If you really scrubbed it well with plenty of soap and water that was likely plenty.

    Not saying it WAS the lacquer thinner but that's one thing that caught my attention.
  8. Phil

    Phil It really *is* a 350...

    I painted a stock pair of valve covers a nice shade of Krylon red long ago. After I painted them I placed them in the oven at 450 for about 30 minutes with the oven door slightly ajar. The paint baked on beautifully and they've weathered quite well over the last 20 years.

    Unfortunately my wife wasn't very pleased. She complained quite a while about the paint smell every time you heated up the oven...
  9. cstanley-gs

    cstanley-gs Silver Mist

    The first time I painted my valve covers, I put them in the oven too, dont remember the exact temp but it was approx 200

    In a matter of minutes that paint bubbled up like crazy!
    messy stuff.
    Had to strip and do it again. never baked it the second time, but they came out beautifully.
  10. Golden Oldie 65

    Golden Oldie 65 Well-Known Member

    X2 on the laquer thinner, or at least the method you used. You can safely use it to clean before paint but you have to dry it, which is difficult because it dries pretty fast by itself. If the surface is not wiped dry after wetting it with the thinner, it will leave a film. I use a Dupont product called Final Klean before painting because, well, that's it's recommended purpose.
  11. Phil

    Phil It really *is* a 350...

    I'd let mine dry to where they weren't tacky anymore. I'd even had a few fingerprints on them that disappeared as the paint heated up and cured. :)
  12. TABuickMike

    TABuickMike Michael Tomaszewski Jr

    Bah @ the lacquer thinner process. Ok makes sense, I have grease and wax remover, I'll make a mental note to use that next time. If all else fails, we'll use it how it is and I'll take temp readings to see how hot it gets. If it isn't too much maybe I'll petition to get a few bucks to have the whole thing powder coated the red we use for the valve covers :beers2:
  13. rmstg2

    rmstg2 Gold Level Contributor

    A Buick red powder coated barbecue would be beauty.:TU:

    Bob H.

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