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USCG paint question

Discussion in 'Technical Discussion' started by Northwind, Jan 15, 2017.

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  1. Northwind, Jan 15, 2017
    #1
    Northwind

    Northwind Member

    Joined:
    Dec 7, 2015
    Messages:
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    Location:
    Norfolk
    I am restoring an old USCG boat (many questions to follow).

    But, the first question is what should be the paint chemistry of the existing paint (need to know for reprinting)? The boat is steel and was used in salt water in the Pacific Northwest. The coast guard had it until 1990.

    The existing above water paint seems in great shape. No rust stains. Few bubbles, cracks or distortions. The USCG did a great job of maintaining her when she was in active use (mothballed in arrid climate since).

    This is a workboat so the finish is never going to be Bristol. But, I would like to upgrade the superstructure to a harder, higher glass finish. And, I would like to make the hull a little more fair and add some depth to the paint system.

    I believe I can go over the existing paint system. One concern is that the new paint chemistry must be compatible with previous finishes. Is this a concern? Will awlgrip, Alexseal and/or Imron paint systems go over the existing paint? How can I test? What is the likely chemistry of the paint system used by the USCG?

    Any and all advice appreciated.
  2. captholli, Jan 15, 2017
    #2
    captholli

    captholli Senior Member

    Joined:
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    Location:
    In The Bilge
    Use a little bit of urethane reducer on a rag and wipe a small area of the painted surface. If the rag doesn't remove the paint than you have a urethane based paint. if it does remove the paint than you have either an enamel or a hybrid acrylic enamel. I doubt that the USCG would spring for a long chain aliphatic urethane like the products mentioned. If it turns out that you do have a enamel top coat , sand it and convert it with a good epoxy primer and then top coat with the urethane of choice.
  3. Northwind, Jan 15, 2017
    #3
    Northwind

    Northwind Member

    Joined:
    Dec 7, 2015
    Messages:
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    Location:
    Norfolk
    Thanks. So, is it the case than you can transition from an older paint system to a linear urathene by using a certain primer?

    What primer would you use?
  4. RT46, Jan 19, 2017
    #4
    RT46

    RT46 Senior Member

    Joined:
    Feb 22, 2011
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    Location:
    Long Island, NY
    please post pics of the former USCG vessel

    thanks
  5. Lepke, Jan 21, 2017
    #5
    Lepke

    Lepke Member

    Joined:
    Dec 26, 2015
    Messages:
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    Location:
    US West Coast. Cruise NW Passage to Alaska.
    Sand the old paint with coarse paper. On steel hulls with aged paint I use a 40 grit and a thick sanding primer. The deep sanding scratches help hold to the old paint. I use a air drive Mirka orbital with a vacuum hook up so I can work over the water quietly without having paint dust go in the water. Primer depends on finish you plan to use. CG probably used enamel and unless you've money to burn, you need to watch the paint cost. I had a marine business. I remember a destroyer used 9 tons of enamel paint to do inside and out.
    Sounds like the Fir.