Sealing the wood in limber holes

Discussion in 'Fiberglass and Composite Boat Building' started by reelpleasure, Feb 27, 2014.

  1. reelpleasure
    Joined: Feb 2013
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    reelpleasure Junior Member

    Curious,

    I have to drill a couple of limber holes through the new stringer pieces on the 25 T Jason.

    The limber holes on the old fir stringers were a simple 3/4" or 1" holes drilled and left the wood exposed.

    When the old stringers were cut out to widen the the engine bed the exposed wood had absorbed quite a bit of water over the last 24 years.

    How do you guys seal the wood grain inside a drain hole?

    I can simply drill some holes and leave them "natural" and let the next owner deal with any structural issues "if any"......

    but I like to do things more right than wrong.

    Any suggestions?

    Appreciated, Reelpleasure
     
  2. Mr Efficiency
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    Mr Efficiency Senior Member

    I suppose you could drill the holes, then pull/push through a rag soaked in epoxy resin, a few times. Or you could insert a stainless tube that fits neatly into the hole, and just seal the end with epoxy. I think I prefer the latter. PVC tube would do.
     
  3. bregalad
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    bregalad Senior Member

    Pipe cleaners work well for getting epoxy into awkward places.
     
  4. Steve W
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    Steve W Senior Member

    wherever I can I epoxy in a piece of G10 or FRP tube, I used to use pvc until I discovered the G10. Its not always possible for some applications in which case if I have gravity on my side i will tape
     
  5. PAR
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    PAR Yacht Designer/Builder

    If the holes are currently soaked, you'll probably want to open them up a bit (bigger hole) and let them dry. Once dry, a number of techniques can be used to get epoxy into the exposed end grain inside the hole. I use small brushes, sometimes I'll take a heat gun to the handle and bend it to a more effective angle. You can make a career out of it, using a pipe cleaner, but they do work, especially on small holes. If you do insert a tube in, saw it flush with the bulkhead/stringer on both sides, so it doesn't trap moisture. If it's a new build, I usually glue in a piece of G-10 and drill that for the weep holes.
     
  6. reelpleasure
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    reelpleasure Junior Member

    Thanks to ALL for the replies.
    I'll triple coat the bare wood with
    West Systems epoxy
     
  7. Steve W
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    Steve W Senior Member

    I didn't finish my last post, what i started saying is that whenever you can take advantage of gravity you can soak the hole with epoxy for a period of time so it can actually soak into the end grain somewhat, at least better than painting it out. We do this all the time in vertical holes such as when potting fastener holes in a cored deck, however sometimes you can do this with horizontal holes too such as limber holes, an example would be say, a limber hole through a keel floor, what I do is drill say, a 1" horizontal limber hole through the floor, drill 2 x1/4" vertical holes from the top of the floor down into the limber hole, 1 will be the sprue, the other the vent. Vacuum out the limber hole and tape over both ends and then inject epoxy down one hole until it comes out the other. Now let it sit for half an hour or as long as you can before it gels then remove the tape and drain it out, use slow hardener to give the epoxy as much time as you can to soak in. This method will give you the best possible protection if you don't go the FRP tube route. Just dabbing it in with a brush or q tip just doesn't get enough in to have any chance of soaking in, especially the top of the hole imho. I use this method for all kinds of things, sometimes I will drill in at an angle from the face, sometimes i will insert drinking straws into the holes to get more head pressure, sometimes you are not draining the epoxy out.

    Steve.
     
  8. SukiSolo
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    SukiSolo Senior Member

    Not forgetting the old trick of drilling the hole and completely refilling with epoxy and a colloidal silica/microfibre (whatever fillers, maybe matching wood saw dust) and re drilling it after it has set. Best if a sealing coat has saturated the clean Fir first as it soaks up epoxy quite a lot. If the redrilled hole is a slightly smaller diameter you have a natural 'pipe' or tube. A light wipe with a round file can let you get the water run to level with the bottom as long as that is sealed too.
     
  9. reelpleasure
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    reelpleasure Junior Member

    OK,

    Today I drilled 1 3/8" holes where I need the drainage openings. I will insert 1 1/4 "PVC pipe pieces.

    Pieces are cut to the correct angles and cleaned up with sand paper.

    Tomorrow I will grind a bit around the drilled holes and get ready for epoxy.

    I have West Systems 105 and 205 hardener. I will mix up a small batch and put

    a couple of coatings inside the hole liberally covering the exposed wood.

    Then I'll coat the outside of the PVC pipe and slip it into the cutout.

    Questions ???

    How long should I let the epoxy coats "sink in" before I set the plastic pipe in place?

    Or should I make this a 2-3 day process? Coating the wood allowing the epoxy to cure overnight with the 2nd coat following day and the the PVC the 3rd day.

    These limber/drain holes do NOT sit in standing water.

    I prefer to get the whole job done in one day.

    Suggestions?? Opinions ??
     
  10. PAR
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    PAR Yacht Designer/Builder

    When the epoxy is just barely tacky or has just lost its tack, apply another coat. The time is dependent on temperature. You should be able to do this in a single day, though is Mass. you'll need to be in the 60 - 70 degree range. If you want speed this up, raise the shop temperature to 80 or more.

    Another good trick is to use the "hot on hot" method. Take a heat gun to the areas where you'll apply epoxy to raw wood. Get them good and hot (150 degrees max) and then wait 5 minutes, so it's cooling down. Apply the epoxy to the warm, but cooling surface. If you can heat the epoxy (microwave for 10 - 20 seconds) to about 90 degrees, then apply, it'll work better. This only works on raw wood applications, but what it does is, force the cooling wood to suck in epoxy, as the air inside the wood contracts (cools). It'll also cure very quickly this way too.
     
  11. BobBill
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    BobBill Senior Member

    Par +1...tedious work, but pays off. I used a product called CPES (very thin epoxy?) to seal after drying the wood and then added the epoxy, wet on wet a couple more times...and then check it every year after...maybe more often...more tedium, but beats having more problems...I also use same methods on parts of house...
     
  12. Steve W
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    Steve W Senior Member

    The high solvent epoxy sealers such a cpes are nice for some things but sealing moisture critical areas not so great, people think that because they are very thin they will soak in more than 100% solids epoxies and they may but only if you can soak the item with a head of pressure for an extended period of time using a method like I proposed a few posts up. When you are trying to paint out a hole you are purely applying a surface coat, gravity is not your friend in this situation and you will not get any penetration into the wood fibers at the top of the hole. 100% solids epoxy is pretty much the gold standard as a sealer coating for wood.

    Steve.
     
  13. Steve W
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    Steve W Senior Member

    Don't spread it out, it will be easy to do it all in a day, its always better to get a chemical bond as you end up with a better bond as well as save steps, as Par said, let it tack, apply another coat thickened, coat the outside of the tube and then insert it with a rotating motion. When you prep the pvc you need to use a grit that is coarse enough to raise some whiskers but not so coarse as to leave any gloss, you are trying to create tooth so nothing finer than 80 grit but if you use, say 36 grit it will not remove all the gloss.

    Steve
     
  14. BobBill
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    BobBill Senior Member

    Yes, I should have noted that I only used the CPES for a sealer, once...then used costs of normal epoxy...I "fingered" it (regular epoxy) on in some places...like weep holes...
     

  15. reelpleasure
    Joined: Feb 2013
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    reelpleasure Junior Member

    Thanks for all your suggestions. The stringer in question is "new" and "dry".


    Finished today, 2 coats of epoxy in the hole heavy wetting the wood and let it "kick".
    Sanded/scuffed PVC pipe coated cut to angle and inserted.
    Let it all kick.

    Mixed up another small batch with some cabosil and filled in around the pipe and stringer. Although the wood is sealed inside around the top of the hole I'll dab in some caulking or 5200 around the top 1/3 of the pipe to seal it up.

    DONE.

    Bare wood lasted 24 yrs. and had only minor water intrusion. I figure @ the least I added an additional 20 years to the 24 years.
     

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