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  • pretreament

    i have a question, on the caswell website for the Epoxy powders. For the pretreatment for that they say to use a zinc phosphate for pretreament. Now for that they say to use use the degreaser too. Now what i heard is you glass bead it first, then power wash it and it should be good. Can someone tell me what the Correct steps are for pretreating it? I want the most simplest but effectivly way possible. I dont want to have to buy 5 chemicals and pretreat it. I would be powder coating aluminum.

  • #2
    We are about to stock an iron phosphate chemical for pretreating before powder coating.

    Watch the web site this week for details.
    Mike Caswell
    Caswell Inc
    Need Support? Visit our online support section at


    • #3
      pretreatment for steel is iron phosphate, and pretreatment for aluminum is zinc chromate,basically. Both methods are very easy to work with and are a good chemical bond (as well as washdown of solvents,etc). When using either of these methods just make sure you let the parts dry sufficiently is all I say. One can't put powder on top of a liquid hidden in a corner and expect good results,right? Blow dry them, even pre-heat in an oven to get it all out. ~fair warning~ . Design behind these two processes are this..... Grease and machining oils are taken of and the open pores of the metal are filled with the remaining chemical. When said chemical dries... a "crystaline" structure is left in it's place (very pretty when looked at under a microscope,actually). When you coat on top of this structure, it grabs onto the crystals, which in turn grab onto the metal producing your bond. That's about the size of it. Think of it as a primer.
      Other than that....the only other thing I can make note of here is that when the process is done right, they look worse than they did before you "washed them",lol. It's ok, they are supposed to. Both the phosphate (for steel) and chromate ( for aluminum) will look streaky and have hues of color in them. Blue for steel, yellow for aluminum. But both metals can have either color in them predominantly, so don't be nervous if your steel is yellow and not blue. That's the light refracting off of the crystaline structure that you just applied. Have fun with it.....after all, it's basically just a modified form of soap truth be known......Russ