electrolysis in wood

Discussion in 'Wooden Boat Building and Restoration' started by skaraborgcraft, Jan 2, 2024.

  1. sdowney717
    Joined: Nov 2010
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    Location: Newport News VA

    sdowney717 Senior Member

    The chiseled slot inner keel and oak floor above
    upload_2024-10-10_21-11-35.png

    Other side of floor
    upload_2024-10-10_21-12-27.png

    A repaired floor behind it going aft. 2 pieces of oak glued and screwed with 3" 316 SS deck screws, one board added to each side

    upload_2024-10-10_21-13-23.png

    And see that red oak floor surface? You can see the grain, but there is a thin coat of Loctite PL on that wood, it is sealed. There are also left over globs of glue from when I glued it to the wood floor.

    To clean anything, hands, etc. use 90% rubbing alcohol. It dissolves the adhesive and prevents it from curing. Get it on hands, it dries, turn dark, and takes a week to wear off your skin. Once cured, nothing will remove the glue, no chemicals I found have any effect on it.

    I have gotten lots on me for decades and have not had any sensitivity issues, it does nothing harmful to me. I hear some people get epoxy sensitized.
     
    Last edited: Oct 11, 2024
  2. sdowney717
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    sdowney717 Senior Member

    That damage could have been easily prevented, just don't use iron or steel fastenings.
    I know everything has a lifespan, that is the attitude for everything made. OEM did other things that I think were really bad, guaranteed to cause severe future problems, like the crazy plywood transoms overlaid with thin slats of mahogany. Plywood edges not sealed for bulkheads or deck openings. Bent oak frames at the chines breaking.

    For the slot repair, I have cut 4 pieces of white oak, will glue them in tomorrow. Then will cut the floor bottom higher and fit a piece to go down touching the inner keel.

    Cut an oak piece as a filler for steel spike hole
    Then fashion some side pieces and the floor will be stronger than new.
     
  3. sdowney717
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    sdowney717 Senior Member

    Getting those SS screws into the oak properly is not an easy task. 316 SS is a softer metal than hardened steel deck screws.
    What I did is first predrill holes in the red oak to be added on each wide of existing oak floor. Including a slight countersink for screw head

    I applied glue to both the floor and the side piece with plastic putty knife.
    Held new wood in place with a support on bottom to keep it pressed up and aligned at top with existing floor.
    Drove in all screws with power drill, no predrill of hole into old floor, those screws are strong and can handle being driven into oak. They have a cutting slot in tip of the screw, that works well.
    Since they are 3.5" long, they stick out the back, so I let that dry.
    Next day remove screws, wow a lot harder to spin out as the PL glue glues them in, but they all come out with effort.
    Then run in the 3" 316 SS deck screws, and glue up other side.

    The new red oak floor pieces also are long enough they fit under those 2 tall stringers that lay on top the floors. I feel the support is very good, actually overbuilt, but really the cost to do this is small. I already had the red oak.
     
  4. skaraborgcraft
    Joined: Dec 2020
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    Location: sweden

    skaraborgcraft Senior Member

    I hear American Red Oak has no rot resistance. How are you going to treat it?
     
  5. sdowney717
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    sdowney717 Senior Member

    It wont melt.
    the wood is completely coated in 100% waterproof PL Premium polyurethane, it wont get wet.
    A couple floors I did 5 years ago show no rot issues. Even so the normal waterline in bow area is below the level of the bottom of these pieces of red oak, the bilge pumps take care of the water, and I have 3 up there. Two 3700 and one 2000 gph pumps. I also boat in salt water creek, boat is not sitting in fresh water. This area of boat in enclosed in a cabin, it gets no rain water

    I am using white oak for keel repairs
     
  6. sdowney717
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    sdowney717 Senior Member

    All un treated woods eventually rot even teak. When I reframed parts of this boat in 2005, I used CCA treated SYP. All of it has remained perfect.

    Including the bottom planks of the lower transom. I used CCA SYP Deck planks, Thompsonized, premium knot free boards.
    And interestingly these sat unpainted in the wormy creek for about 4 years and got almost no worms, just a few very small holes.

    Our docks in US, most are built with CCA SYP wood, and they hold up well until storms take them out.

    upload_2024-10-11_5-20-43.png

    close up showing PL in seams for 10 years and not a single issue. All bung holes filled with PL.

    I experimented with using Loctite black PL roof and flashing poly, and it failed, scraping off barnacles in the water caused the coating to come off, coating got soft in the water. You can see some barnacle bases still on the wood. Exposed to wormy barnacle infested warm water for 4 years.

    upload_2024-10-11_5-21-54.png
     
  7. sdowney717
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    sdowney717 Senior Member

    PL premium polyurethane mixed with sawdust used as a filler on bottom planks for 20 years, perfect, no issues, like the day I put it on there.
    upload_2024-10-11_5-28-59.png

    close up, all seams and bung holes filled with Loctite PL. Now there is a technique here to use, mix in up to 30to 50% sawdust, put on wood using a plastic putty knife. The stuff swells up a lot. Press it back down using back and forth motion, you can hear the air bubbles crackling, then cover it with plastic cereal bags. Can even clamp the bag down, if you do that you get a very flat surface. Sets ups fast. After 15 to 30 minutes, it is basically not going to do anymore swelling. When cured surface feels slick. If very cold be next day ready to sand or use. I just always wait till next day to sand smooth. Paints stick well to this. If you do not press it back down, you get air blisters. See part of the attraction of using this swelling adhesive, it squeezes itself into all crevices. Fill a crack in wood, and it follows the cracks swelling to fill free spaces in wood. I have used it between keel timbers, I use a broad putty knife and force it into the cracks, then lay knife flat against wood with a load of glue and press it hard into a crack over and over, and it is forced deep into the timber. Sort of like injecting it into wood.

    I do think for planks seams, your are better using it straight, with no sawdust. I think it allows for a better seal as it is more compressible and expandable as planks move
    upload_2024-10-11_5-29-56.png

    You could also use a thin light coat as a water barrier on wood, but it is not UV resistant, will need paint. I think as a water sealer on plywood boat bottom would be very good. IT will seal everything and no water can get past it. this PL is durable long term 100% waterproof, and I proved it. Tube also says 100% waterproof. You got to use 100% waterproof glues on boats.

    By thin coat on plywoods, I mean use a plastic putty knife and spread on wood, then press knife hard on wood scraping up excess glue. A little glue then goes a long way to cover a large surface. You will see the glue saturate the wood surface.
     
  8. skaraborgcraft
    Joined: Dec 2020
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    skaraborgcraft Senior Member

    I made my comment before your pictures finished loading (i have a slow connection). Yeah, out of the bilge like that should be fine. I have used pressure treated wood in the past. Still surprised your glued caulk seams have held up.
     
    sdowney717 likes this.
  9. gonzo
    Joined: Aug 2002
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    gonzo Senior Member

    Everything has a life expectancy. Blaming the builder for normal wear and tear is not reasonable. It would be as if you blame an auto manufacturer because you need new tires.
     
  10. sdowney717
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    sdowney717 Senior Member

    They are what they are.
    I have modified my thoughts on recoating the hull. Still using 3M 5200 as a base layer, then maybe use the Durabak-18 Smooth Marine liner on top.
    It is a little cheaper costwise by gallon. Will keep thinking on it. Nothing is set in stone yet. I was told by their rep, all Durabak 18 is the same marine liner or bedliner. There is a navy mil spec coating that has a better fire resistance.

    Boat Paint & Marine Paint - Slip Resistant | Durabak (durabakcompany.com)

    I talked with their support, and it can be used underwater. They said use several thin coats. And it will stick to 5200 and itself well.
    There is no mixing of any hardener.
    They were not clear on surface hardness but said pencil hardness of 2H to 3H.

    Here someone used it on a boat hull underwater and says holds up, boat gets beached on sand and it has not worn.
    Keelguard by Durabak (youtube.com)

    Of course many coats adds up the price. Guy in video used 7 coats, likely to just use up a can as you can't save a can once opened
     
    Last edited: Oct 12, 2024
  11. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    About electrolysis damaged oak. My experience, it is only where oak is partially wet and partially dry. Where oak was constantly submerged in salt water, there was no iron spike rod caused damage to inner keel. The damage was at the very last front floor, partially wet. I think that partially dry, the iron produced acids become concentrated greater than in submerged oak where the acids are flushed away by osmosis. We all know acids when the water dries, become more concentrated. The front spike when I removed it, was completely gone where it entered the oak inner keel, and other spikes installed in continually wet areas where only partially eaten. Maybe rust also is worse with more oxygen.
     
  12. sdowney717
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    sdowney717 Senior Member

    Sure I can get that, but since I always seem to end up with old stuff, and have to deal with it, I see this kind of thing all the time.

    I bet bronze prices have gone up a lot more than steel prices the last 50 years. And I wish they had used bronze spikes or even no spikes at all. I figure those spikes were used to align parts during construction as after everything is screwed together the floors are not going anywhere without them.
     
  13. gonzo
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    gonzo Senior Member

    It is unreasonable to buy old stuff and criticize it for not being is as new condition. Old stuff is cheap because it has already passed its expiration date. I buy a lot of old stuff too. Many are good enough for a couple of years before they need to get junked.
     
  14. Rumars
    Joined: Mar 2013
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    Rumars Senior Member

    The spikes aren't there to keep the floors aligned to the keel, that could have been accomplished by one or two small toenails. Their job is to keep the keel connected to the rest of the boat, and yes they have to be that big. Otherwise all that's keeping the keel from dropping out are the small screws or nails in the planking rabbets, and since you have inletted frames, the small fasteners in the frame heels.
    The only reason why your boat still works despite you removing some of them is because the others are still doing their job, otherwise the garboard would tear along the fastener line like a ripping a stamp along the perforated line.

    The simplest way to use 5200 to waterproof your bottom is double planking. Rip some wood to 1/4" and staple it over the fresh 5200 with copper or stainless. You don't need to taper the planks, you can use inserts in the gaps.
    The wood is there to protect the rubber from abrasion, you will be able to scrape and sand your antifouling. Fabric won't offer the same amount of protection regardless of what you use, if the fabric doesn't rip the 5200 will.
     

  15. sdowney717
    Joined: Nov 2010
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    sdowney717 Senior Member

    I wont be pulling any more spikes as all the others are dry. However I can imagine rusting and rusted away disintegrated spikes after a certain amount of time are not really doing anything at all for boat integrity. And the ones I pulled certainly have not done anything for at least the last 15 years. The front part of the skeg and keel join together and there are many 1/2 inch long bronze bolts all along the bow curve. I figure they help hold it together too. None of the iron spikes were fully intact, the semi intact spikes their bottom ends were like thin tails.

    Inside at the bow is a long curved large 4" wide and 6" tall piece of Douglass fir and it also must be holding the keel on at the bow. It runs all the way up to the top deck on the inside. Bronze bolts are close together in the bow and further apart midships and aft.

    I pulled out 8 so far and they are in good shape. I used a power drill and wire brushed to clean bronze. Then I coated them in JB Weld. I plan to pull some more later after they go back in.
     
    Last edited: Oct 12, 2024
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