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Soda blasting vs. aluminum oxide

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  • Paint: Soda blasting vs. aluminum oxide

    Hi all-- I'm restoring my '53 Starliner, body off. Frame is powdercoated by a previous owner who stalled out on the project. I'm now preparing the body to go back on the frame. I've just purchased a combination soda and media blaster from Harbor Freight, a large one they sell. I have a large compressor as well. I tested a couple of spots, and the soda lifts paint right off beautifully, but not rust. The aluminum oxide in the other tank takes off everything, and leaves a slightly rough finish.
    Do any of you have actual experience with these media? My concern about the soda is the lack of adhesion of coating and paint products afterwards. I know the soda leaves a residue, because the test spot did not rust when left outside after a rain, even though i read it must be washed off with water... rain, in my experience IS water...
    and the aluminum oxide rough finish makes me think I'll need to spend lots of extra time painting the body with high-build primer and blocking it all out to regain a smooth finish.
    How about a step-by-step how-to by one of you body and paint experts who has yourself taken a car through blasting and paint, and then spent enough time around the finished car to tell that the finish actually stayed on the car?
    Also helpful would be describing the steps necessary to seal, protect, and soundproof the under-body, and the products used?
    Maybe there's a book out there somewhere that covers all of this?
    I love to learn, but not the hard way... Thanks in advance!
    1950 Commander Land Cruiser
    1951 Champion Business Coupe
    1951 Commander Starlight
    1952 Champion 2Dr. Sedan
    1953 Champion Starlight
    1953 Commander Starliner
    1953 2R5
    1956 Golden Hawk Jet Streak
    1957 Silver Hawk
    1957 3E5 Pick-Up
    1959 Silver Hawk
    1961 Hawk
    1962 Cruiser 4 speed
    1963 Daytona Convertible
    1964 Daytona R2 4 speed
    1965 Cruiser
    1970 Avanti

  • #2
    Funny you should ask, Dec. 2014 Car Craft has all you asked for.

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    • #3
      I don't use soda for just the problem you mentioned. If you don't neutralize it properly you will have adhesion problems. As for the rough surface left by aluminum oxide or sand, this is not a problem. In fact it is a benefit because it saves you a lot of sanding. I think everyone agrees that epoxy primer is the best product to seal and protect bare metal. The metal must have a "tooth" for the best adhesion. This is normally achieved by sanding the bare metal with 80 grit paper, but the blasted surface already has the necessary "tooth".

      You will not have to do any additional sanding to get a smooth surface to build from. Just spray a couple coats of unreduced or slightly reduced epoxy on the blasted metal and you will get a nice finish. Once you spray your epoxy primer, let it set for a day and then spray your high-build and start blocking. As long as you spray the high build with in the re-coat window of the epoxy you will save yourself a sanding.

      I am currently in the process of blasting and painting my car. I am using SPI epoxy over the blasted metal. I am reducing the SPI about 5 to 10% with a slow reducer. The finish comes out with a slight sheen like a semi-gloss paint. In fact the frame and suspension parts are just getting a couple coats of black epoxy primer with no top coat.

      Good Luck
      Wayne
      "Trying to shed my CASO ways"

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