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Technical Painting Radiator

Discussion in 'The Hokey Ass Message Board' started by Willywash, Oct 1, 2021.

  1. Willywash
    Joined: Sep 18, 2019
    Posts: 76


    Just got a 32 grill for my 31 Model A. After fitting, I noticed you can see a lot of aluminum radiator and condenser. Thinking about spraying the front of the two black. Would this effect cooling and should I prime, then paint with high temp engine paint? Want to make sure the paint will adhere and not effect cooling in anyway.
    dana barlow and Bandit Billy like this.
  2. A single coat of flat black will be fine. The radiator will not get hot enough to cure high temp paint and it will flake off.
    blowby, loudbang, SS327 and 4 others like this.
  3. Moedog07
    Joined: Apr 11, 2011
    Posts: 250


    I have ran painted and unpainted depending on the look I wanted. No noticable difference in cooling temperatures. Have good air flow for the radiator to remove the heat.
    loudbang, mad mikey and Blues4U like this.
  4. squirrel
    Joined: Sep 23, 2004
    Posts: 50,276


    I also use just enough spray can black to cover it.

    You'll probably find that it gets chips in it if you drive the car much...
    SS327 and rockable like this.

  5. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 8,161

    Bandit Billy

    My 41 PU under construction at the moment. Brice Thomas radiator and Vintage AC condenser. I don't do the zip tie thing through the core, I welded brackets onto the radiator and condenser to mount securely with a nice air gap between them.
    I painted it with Eastwood 2K Hot Rod Satin Black to resist chipping. Respirator required. Not cheap at $27 per can and It took two cans! A lot cheaper options out there but taking the truck apart to repaint the radiator in a few years is not going to happen if I can avoid it.
  6. tiredford
    Joined: Apr 6, 2009
    Posts: 546

    from Mo.

    I use Ace hardwares cheap flat black and just mist it on there enough to cover, no problems
  7. Budget36
    Joined: Nov 29, 2014
    Posts: 7,556


    Myself as well. Flat black.
    Not that I’d admit to using an aluminum radiator;)
  8. Blue One
    Joined: Feb 6, 2010
    Posts: 11,191

    Blue One
    from Alberta

    Last edited: Oct 1, 2021
  9. CyaNide
    Joined: Mar 2, 2006
    Posts: 239

    from Texas

    Eastwood carries a satin and glossy radiator specific paint. I have never used it so I have no info on that. It says that it won’t effect heat transfer.

    loudbang and mad mikey like this.
  10. Blue One
    Joined: Feb 6, 2010
    Posts: 11,191

    Blue One
    from Alberta

    As compared to the heat dispersion powder coating that I had applied that helps with cooling.
    loudbang likes this.
  11. Bob Lowry
    Joined: Jan 19, 2020
    Posts: 757

    Bob Lowry

    Have always painted them semi-gloss black, with Krylon spray can. Dries fast and easy to touch up.
    texasred and mad mikey like this.
  12. SilverJimmy
    Joined: Dec 2, 2008
    Posts: 333


    Probably 25 years ago I drove into the radiator shop on my tool route. John the owner tells me he needs a new paint gun for painting radiators. So I do my best sales pitch on all the different paint guns I had on my truck. When I’m done with my spiel, he starts laughing and tells me he isn’t painting cars, he’s painting radiators. He grabs my catalog and flips thru it till he finds his “paint” gun. He wants a solvent spray gun, the kind with a hose you drop into a can of solvent and hook up to compressed air. He tells me that the old timer that taught him the business showed him the trick to paint radiators. He used Rustoleum gloss black and thinned it with gasoline. That made the paint thin like you needed to not inhibit heat transfer but still coat and protect the bare copper and brass from road salt. He did it that way until the plastic radiators changed the industry and he got out of the business. Notice how many less radiator shops there are today?
  13. krylon32
    Joined: Jan 29, 2006
    Posts: 7,585

    Alliance Vendor
    from Nebraska

    I did one a few years ago and just used common Krylon satin black. Seemed to hold up fine.
    mad mikey likes this.
  14. Yeah but I'd paint it red or blue :D hey! Red white and blue! :cool:
  15. Rusty O'Toole
    Joined: Sep 17, 2006
    Posts: 9,608

    Rusty O'Toole

    One or 2 thin coats of flat or semi gloss black will enhance heat transfer. I would use a spray bomb of barbecue paint, that stuff is tough as hell. I bought a car the previous owner had 'touched up' with the stuff and had a hell of a job cleaning it off. It is MUCH tougher than regular rattle can paint.
  16. I wouldn't over-think it. I personally just spray the "line-of-sight" method to hide any bright metal. I use whatever black I have in the garage.
    That means I don't spray the underside of the fins or the backside of the radiator, unless I want to "hide" the back for some reason.
    The only time I've ever done a touch-up is because I've bumped the radiator somehow.
    Bob Lowry and Blues4U like this.
  17. Did my new radiator , that I got after the accident I had in Eastwood flat black Radiator paint. Looks great, no issues, and I race and run my hot rod HARD.
  18. rockable
    Joined: Dec 21, 2009
    Posts: 3,625


    I bought a 54 Chevrolet that someone else built. I immediately had overheating problems and chased my tail replacing water pumps, thermostats, etc. I had taken the radiator out 2 or 3 times to take it to a repair shop until it finally developed some leaks. I took it back to the shop to get it repaired and the guy called me and said, "Man, I don't know what kind of paint they used on this radiator but I've run it through the tank twice and it's not coming off." I said, "Repair the leaks, don't paint it and I will pick it up."

    Long story short, the radiator had been powder coated, fins and all. I spent a bunch of hours using paint stripper, toothbrushes, toothpicks, etc to get it cleaned up. I then sprayed a light coat of black paint on it and never had another overheating problem again.

    A radiator is designed to give up heat, not keep it in. The powder coating on the fins and tube was insulating the ability of the radiator to give up heat. Powder coated tanks are probably ok but don't overdo the paint on the tube and fins and never powder coat them!
    loudbang likes this.
  19. Old radiator shop guy here in town mixes flat black & gasoline, that's what he sprays them all with after he vats them or re-cores them.

    Years ago I painted my old pickup including my grille and it didn't take too long to realize the paint and clear coat caused the radiator to over heat. HRP
    SilverJimmy and catdad49 like this.
  20. Roothawg
    Joined: Mar 14, 2001
    Posts: 22,066


    How is that even possible? Is it petroleum based paint? I have problems with fisheyes and I have 3 filters and a desiccant trap.
  21. Blue One
    Joined: Feb 6, 2010
    Posts: 11,191

    Blue One
    from Alberta

    Read my post above. I had my new aluminum Griffin rad powder coated fins and all with this special high tech coating.

    Check out the link
  22. hardtimesainit
    Joined: Jan 24, 2009
    Posts: 608


    Eastwood has a spray can for this job. Ive used and it has non shiny look. Thanks
  23. rockable
    Joined: Dec 21, 2009
    Posts: 3,625


    I'm not saying they don't have special coatings that could work well. I'm just saying mine was coated with plain old powder coat and it insulated heck out of my copper/brass radiator. Of course, it was probably done 15 years ago, too. It did look pretty, however. :D
    Blue One likes this.
  24. catdad49
    Joined: Sep 25, 2005
    Posts: 5,317


    I knew radiator shops used thinned paint, but I thought it was something a little less flammable than gas! El cheapo flat and just enough to cover works for me, Stay Cool.
    Hamtown Al likes this.

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