Stripping lapstrake

Discussion in 'Wooden Boat Building and Restoration' started by tx-scooter, May 27, 2009.

  1. tx-scooter
    Joined: May 2009
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    tx-scooter Junior Member

    What is the best way to strip a lapstrake? heat or chemical? want to refinish but dont want to hurt the integrity of the adhesive between the laps.:?:
  2. alan white
    Joined: Mar 2007
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    alan white Senior Member

    It's probably between heat gun and Zip strip, or both. Sanding is too hard on the wood, at least using a grit that would remove paint.
    i'd start with a heat gun and a 2-3" putty knife, and finish with a careful application of paint remover, followed by light sanding with 80 grit, priming, and then puttying/filling, sanding with 150 grit, priming again, and finish coats.
  3. PAR
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    PAR Yacht Designer/Builder

    It depends on the boat, when it was built, what if anything was used in the laps, etc.

    Many older lapped builds don't have anything in the seams, just wood to wood contact. Others may use thick varnish or shellac, while others may have used polyurethane or polysulfide. If it's a vary modern design it also could have epoxy.

    Stripping paint off a washboard surface is always going to be difficult.

    If it's a painted finish you're after, then any method will do, because putty and paint hides everything. If it's a bright finish you have to be especially careful. Chemicals can discolor the wood and possibly attack seam sealants. Heat can scorch wood, which is difficult to remove without grinding through a substantial portion of the planking.

    Use chemicals in small areas at a time. Don't try to get all the paint in one shot, several applications will be better then one. Scrapping is the best on these surfaces, but the underside of the laps will drive you nuts. Sanding will also cause you fits on the underside of the laps. This is worse with plywood planking rather then solid lumber.

    Personally I'd just scrape it back to well stuck paint, prime any bare areas and paint again. If the paint is well stuck, then it doesn't need to be removed, just refreshed. Fill any low spots, prime and paint as needed. Starting over from raw wood is not necessary, unless the paint is coming off wholesale and bare wood is visible. In other words, scrape and sand what you need, to provide a solid, well stuck base, fill, prime and paint.
  4. tx-scooter
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    tx-scooter Junior Member

    thanks guys

    it is a 1965 barbour, it will be painted. it seems the last paint applied was the wrong kind, it is peeling in very large chunks. the laps are leaking in only 1 spot about 12-18" so will need to repair that also.i would like to keep the cuddy bright mahagony, but has several places with some rot, at corner of windows ect, so may end up painting.
  5. Lt. Holden
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    Lt. Holden Senior Member

    I would dry scrape any and all loose paint using a "Bahco or Sandvik' carbide scraper (they are the same and both have orange and black handles) I have one with about a 2 1/4" straight blade and a smaller one with a 5/8" or so triangular blade and then proceed as suggested. I would try stripper before heat for the aforementioned reasons.
  6. keith66
    Joined: Sep 2007
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    keith66 Senior Member

    Some years ago i aquired several Yachting world dayboats, these were planked in mahogany but were often sprayed with polyurethane varnish when built.
    Obviously they were an absolute ******* to strip clean. I found the ideal remedy in the shape of a portablast sandblasting gun, used for car repairs. It sounds brutal but was actually very effective, using fine grit the finish was good enough for varnish. The biggest job i did was stripping the interior of a 28 ft Saunders launch which came out perfectly.
    Word of caution on no acount try this on a softwood (pine) planked boat as the difference in hardness between the growth rings will leave a dreadful surface resembling an old seafront shed!
    And you need a good respirator!
  7. PAR
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    PAR Yacht Designer/Builder

    Soda ash is a sand blaster will also work, without raising the grain.
  8. wardd
    Joined: Apr 2009
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    wardd Senior Member

    saw something on tv some time ago about dry ice blasting
  9. Luckless
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    Luckless Senior Member

    I've worked around a renovation job using dry ice blasting. It is rather abrasive, and ate into the wood fairly deeply and randomly. The value of dry ice is that it evaporates, and does not stain. It is not however, an overly gentle blasting medium when it comes to wood.

  10. Oyster
    Joined: Feb 2006
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    Oyster Senior Member

    As a side note I would be interested in knowing a bit more about your Barbour boat. Did you buy it or has it been in your family and the likes? Thanks, oh photos by some chance? I would be tempted to just sand the boat really good even though it maybe a bit more work after knocking off the loose paint. The edge of the planks are a real bugger. So do those last with some floor paper on a small block of wood. Do not under any circumstances use a drill sander on the boat if you chemically strip it or use a heat gun. The type of paint thats on the boat also should give you some concern if the boat has never been wooded too and has had enamel paint on it. If you have small children beware too of the dust if this is applicable.
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