What should I finish a new plug in?

Discussion in 'Fiberglass and Composite Boat Building' started by Thin water, Jul 6, 2007.

  1. Thin water
    Joined: Aug 2005
    Posts: 100
    Likes: 2, Points: 0, Legacy Rep: 26
    Location: Central Florida

    Thin water Senior Member

    I have made my plug in thin plywood for a kayak and am almost ready to complete fairing it out and coating it in it's final coat. I have used arcillic enamel auto paint in the past on smaller plugs. They looked perfect when I was done with them but even after 5 coats of good mold release wax and a heavy coat of PVA they still stuck in the mold. I managed to get them all out but most left 1/2 their paint stuck on the gelcoat in the mold and I had to scrape it out. Pictured is an electronics box I made in a mold that my plug stuck in. It took me about 3 months to get all of the plug out of the mold with out hurting the mold. I did not use any screws so I was able to break out the plug in little peices.

    I was considering using gel coat on the plug but it would suck to have to sand that much of it to a smooth finish.

    JIM

    [​IMG]
     
  2. alan white
    Joined: Mar 2007
    Posts: 3,731
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    Location: maine

    alan white Senior Member

    Use gelcoat anyway and enough wax. You also need draft angles for releasing squarish items. So you don't have to sand so much, formica is handy. It's very non-porous, flat, cheap, and adheres to a substrate with rubber cement. Good for a deck, panel, or chined hull. Also there is Kydex, which has other names, that stuff found on Commercial kitchern walls and bathrooms. It usually has a pebbly surface, great for certain items.
    The wall stuff is also sometimes made of fiberglass, which Home depot has.
    In any case, look at improving your waxing and I'd bet you would have better luck. Many here could help you with the best product and means of application---- not up my alley.

    Alan
     
  3. JRL
    Joined: May 2007
    Posts: 83
    Likes: 2, Points: 0, Legacy Rep: 25
    Location: Palm Beach Gardens, FL

    JRL Im with stupid

    How long did you let the auto paint dry? Im assuming you have a air gun vs. a spray paint can? My guess is that you didnt wait long enough and some type of reaction happend.

    Try and find any polyester based primer. Wet sand it to 1500 and then polish it. Its a proven method for plug finishing. OR, spray your plug with polyester primer, and finish it with thinned clear gelcoat (with wax additive). Ive thinned gelcoat up to 20% and the finish comes out great, similar to automotive paint. Just takes a while for it to cure.

    Duratec Surfacing primer is what I use.
     

  4. Thin water
    Joined: Aug 2005
    Posts: 100
    Likes: 2, Points: 0, Legacy Rep: 26
    Location: Central Florida

    Thin water Senior Member

    I wish I had thought of the formica before I made the plug. I will try it on the next one.

    The primer sounds good. The electronics box plug was professionally painted by a friend of mine at a body shop. It dried about one week. I read on PVA that it can bond to automotive paint, it did. Another plug i made I used spray can paint. several different coats. The good thing about it is that it 's bond between coats sucks so it came out of the mold and left layers of paint behind where it stuck. I used MDF ply for that plug so I was able to use a pressure washer to blast out most of what stuck.

    I have made a few molds that were not perfect and popped out a part, used gel coat to fix imperfections then splashed another mold from my part. I have always had a clean easy release when doing this.

    I will give the Duratec surfacing primed a try.

    Thanks,

    JIM
     
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