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Thread: Sikaflex over epoxy - fixing leaky fore-deck

  1. #1
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    I am going to cut a long story - short !

    Am in the process of carrying out a major repair to fix fore-deck leaks.

    Used a circular saw followed by a router to weed out out 48 fancy strips of white wood ( marfim , 5x5 mm)that were set with epoxy-glue in 5x5 mm recesses on the mahogany planking of the fore-deck. A back-breaking job.

    BTW, these recesses are due to the overhang of adjacent plank-ends butting-up against each other.

    Having used a 5/16 straight-cut bit on the router, the resulting rectangular grooves on the mahogany-planking now fit the new white-wood ( marfim )7 mm wide X 5mm deep strips perfectly.

    To-morrow morning, I plan to seal the new grooves on the mahogany planking by swabbing with two-part epoxy diluted down with 5-8 % acetone (by volume). Similarly, seal the white-wood srips too. The epoxy is a slow-curing type (7 hours).

    Some 5-6 hours after doing this, that is, just before the epoxy cures, plan to squirt Sikaflex (polyurethane) sealant into the grooves and then tap-in the new white-wood strips. Is this OK ?

    Would welcome any suggestions and/or advice.

  2. #2
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    It is my experience that polysulphide is incompatible with uncured Epoxy. Do a test piece to see what happens before doing the actual deck.

  3. #3
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    Why mix wet epoxy and Sika together - sounds like a recipe for disaster? Why not just epoxy the new strips in?

    Sikaflex works well in one plane - eg, sealing seam edge to seam edge - where it will stretch up to 400%. If you add another plane to the equations eg, by having it touch both sides and the bottom of a seam, it will fail. That is why you should use bond-breaking tape in seams.

    I'd go with the epoxied strips with plenty of ooze factor. I'd also omit the acetone.

    Ian

    Ian

  4. #4
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    Originally posted by igatenby:
    If you add another plane to the equations eg, by having it touch both sides and the bottom of a seam, it will fail. That is why you should use bond-breaking tape in seams.



    Ian
    Would you mind tell us where you get such narrow tape?

    And how do you actually get it into the botttom of that tiny slot?

    Does this require you have really tiny fingers?

    Or does the sugestion "SHOULD USE" really mean nobody actually does..

  5. #5
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    I'm not sure why you would want to do it that way, but to answer your quesiton, polyuretane generally adheres extremely well to cured epoxy. (The reverse is not true.) However, I would wait for the epoxy to cure, as the solvents in the Sika might create a problem with partially cured epoxy.

  6. #6
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    Seems like from what he is saying the strips fit perfectly in the grooves before any glue is added. If the epoxy he is using as a sealer hardens, he wont be able to fit these white wood strips into the grooves cut into the mahogany.
    So the idea is to place the strips before the epoxy has completely set?

    If you are worried, I would simply test it out on scrap wood. Then see how strong the bond is. I think it should work.
    Are you trying to save on epoxy by using the polyurethane?

  7. #7
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    Igatenby is absolutely right. Check the Gougeon Brothers' epoxy "bible" on this one. You are setting holly strips in the seams, as I understand your post. They should be epoxied in place. While CPES is often used in such applications to make sure the bond runs into the wood (forget thinning your epoxy... you're asking for trouble) epoxy adhesive is entirely suitable on bare wood for gluing purposes. Glue the strips in with epoxy. You may wish to thicken it with colloidal silica to prevent runs and mess and increase the strength of the cured epoxy. After it cures, sand the deck fair. There is no need for Sikaflex at all. If you properly epoxy the splines in place without voids, you will have a solid deck that should not leak. I say "should" not leak, because as you are using epoxy, this will depend on the stability of the deck itself. If it isn't stable, it will shrink and swell and no amount of anything will prevent eventual leaking. Holly splined decks are used on smaller surfaces and on runabouts which are often kept in covered berths, so it is suitable. For decks of larger surface area which will suffer the outrage of the elements full time, about the only ways to go are faux planking over plywood (better than nothing) or traditional laid and caulked decks (the best option).

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    I've had experience with epoxy and polyglop and wish I didn't.

  9. #9
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    Would you mind tell us where you get such narrow tape?

    And how do you actually get it into the botttom of that tiny slot?

    Does this require you have really tiny fingers?

    Or does the sugestion "SHOULD USE" really mean nobody actually does
    Locally - Scomars

    How - read this: How to lay teak

    Tiny fingers: try A 5mm wide stick - or some other tool about that size that you may have

    Does anyone do it: Absolutely! I'm about to do 500+ metres of it. Seen too many failed seams to not prime and bond-break.

    Ian

    Edited to fix the link

    [ 10-03-2005, 04:12 AM: Message edited by: igatenby ]

  10. #10
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    My computer packed up yesterday morning. I went off to the boat hangar did some prep work and called home to ask what WBF had to say about my query.

    As your helpful messages were relayed over my mobile phone , I decided to go it slow !

    The white-strips are 7mm x 5mmm and they fit snugly in the mahogany substrate that are 5/16 " by 5 mm. No room in there presently for epoxy or polyurethane.

    I do not wish to do this deck again for leaks , not in my lifetime if I can help it .

    So on that note, let me tell you that the 5mm x 5mm white-strips I took out had been epoxy-glued into the mahogany substrate some 7 years ago .

    That is why I thought of polyurethane sealant to handle the interface between the strips and substrate. You know, seal the strips and substrate channels first and then polyurethane them together. Please note that there is currently no room between these components for sealant to fill the gap

    From what Bob Cleek says, seems that my deck is doomed to leak, if not now, at least in the near future.

    What do I do ? For instance, donīt mind hand-planing the strips and turning them into say 5mm x 3mm, leaving some room for sealant - or even epoxy, if the latter is deemed better.Remember this is tropical, sweltering heat etc..

    Want a sure-fire solution ......the deck will wait till the many Wood Docs on this board come up with the best compromise ....

    Thanks a mil to all....will look up WBF later this evening

  11. #11
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    Carrioca, FWIW to you.
    I have had good luck gluing wood together with permaflex. It is always flexible. If these strips are clean wood going into clean slots, it ought to stick well and not leak. It will also sand off. It will soak into the wood ever so slightly and is not a clear color so you might have to sand a little deeper to get the wood clear, but I am not saying it would color the wood deeply like a stain might do. I use the sand color which is a light yellowy sandy color.
    I laminated some wood together and it does not come apart. I even glued 1/2 inch wood plugs into frames and they dont pull out.

    www.sanitred.com

  12. #12
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    I wanted to add, those plugs in the frames are holding planks. Screwed planks up tight and under pressure they have not budged a bit. I was using epoxy but as it got really cold in december and january, the epoxy was not setting up and taking too long to harden, like weeks.

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    I don't think it really matters that your filler strips are a tight fit. Epoxy would hold them in just fine. Epoxy is "gap filling," but that sure doesn't mean it won't stick if there's no gap! I don't think polysulfide compound will be a better adhesive at all. Lay your strips in epoxy, finish fair and then apply CPES and several good coats of varnish. If you keep it covered and the varnish maintained, it should do alright.

  14. #14
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    sdowney717 welcome on board and thank you for the tip. Sanitred, a polyurethane - and not a polysulfide , which I have had dismal results with - does seem promising, especially the high-UV formulation. Yes, the slots in my mahogany decking have been bared to raw wood, and the white-strips are newly cut but dried marfim wood.

    Sanitred does seem to have worked wonders on your restoration as per your account. But as it is unavailable in Brazil, DHL or Fed Ex will charge me at least US$ 300 just for shipping and customs-clearing fees. Plus cost of purchase + customs fees.

    Have you compared Sanittedīs holding tenacity, plus resistance to rupture, with that of say 3M 4200/5200 and/or Sikaflex ? Are you familiar with the latter polyurethanes ?

    Bob Cleek, my boat will not be sitting under cover as of this coming summer as the restoration work is about done and I plan on leaving it out on its mooring.

    After my sore experience in 1998 with gluing the white-strips with epoxy-glue on the same mahogany deck, I am not likely to do it again And recourse to a circular-saw to bust the fellas, prior to weeding them out with a router

    What if I, say, :

    1. Shaped the rectangular X-section white-strips, some 50 in all - with a Dremel-type tool - to form a V X-section, 7 mm at deck surface tapering out to 1-2 mm at the bottom of the deck slot ?

    2. To seal the wood, apply thinned 2-part epoxy (max 10 % acetone)to white-strips and deck slots; then let these cure.

    3. Put a strip of 7 mm wide waxed-paper at the bottom of the slot for its full length, as Ian(igatenby) has suggested; some say parchment paper (draughtsman stuff) also works well.

    4. Finally, squirt Sikaflex into the slots and tap-in the white-strips with a wooden mallet.

    What objections could be raised, if any ?

    Has anyone thought of this and/or done it before ?

    What results could I expect ?

    Anyone care to guess ?

  15. #15
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    Seems like you are making this a lot harder than it has to be. Dry fit the white strips with a tiny bit of play. Run some unthickened epoxy into each slot and along the sides and back of each strip. Smaer some thickened epoxy into the slots and tap the strips home with a mallet and a long block. let it all set and scrape and sand it smooth. CPES the whole shootin' match real well, let it set and then varnish.

  16. #16
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    Wyndham,

    Do excuse my frankness, but do you have on-hands experience of what you have proposed ?

    Why not use Sikaflex, which should allow for movement - seasonal as well as structural - between the strips and deck substrate ?

    Please note that epoxy-gluing was used in 1998, with dismal results. It could be that it was not done as it should have - I simply donīt know, as I was not present on location at the time.

    All I can attest to is the unholy - and back-breaking chore - of undoing what was done.

    And I need to do it right, now, once in for all.

  17. #17
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    If you are using that insert strip of wood for the color efect I can understand, but if that is not important I will tell you how a fellow who worked at Egg Harbour made his teak decks.

    FIrst thing is NO plywood or underlayment was used...just the cross supports for the deck at aprox 8 inches apart.

    The teak was about 1 inch thick maybe a little thicker, call it 25 or 30mm for you metric guys..and maybe 3 inches or 75mm wide...each board was random length of 4 to 6 ft...or maybe 1 meter to 2 meters long..

    He cut a rabit along one side with a table saw and as best as I recall that left 1/4 to 3/8 wood at the bottom, and the sawblade took away maybe 3/16 inch..

    When these boards were laid next to each other he had what looked like a slot 3/16 or 4 mm wide and 3/4 or 18 mm deep.

    Butt joints looked just like the side joint.

    He screwed the deck to the supports allowing for wood plugs.

    After the wood plugs were put in and I dont remember what he used but it was in a caulking gun and was black in color.

    Deck was then samded with a belt sander to make the plugs level and look good. Vacumm up the dust.

    He then covered the deck, not the bottom of the slot with masking tape and used a 2 part black thiokol type caulking compound to fill those slots. this was put in with a putty knife and a trowel much like spreading mastic for laying tile.

    Knife it all off, as much as you can anyway, then pull up the tape so it left the black rubbery stuff just a tape thickness above the deck.

    That's it, finished..

    I didnt sleep under it, he did.
    So I have no idea if it leaked or not.

  18. #18
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    Carioca, Wyndham is right. Also, Gary E. is describing the proper way to lay a traditional deck. Now, so far, I haven't figured out WHY those "white" wood strips are in there. That technique is used on finely finished, varnished decks and hatches on runabouts and such, not meant for much walking on. Is this the situation with your boat, or are these regular decks that some idiot put wood strips into instead of seam compound?

    Anyway, look, do it your way if you want, but take it from somebody who has used a lot of Sikaflex on decks and doesn't anymore. Sikaflex doesn't hold up well in the UV (sun). It will dry out and harden. Also (another lesson from the school of hard knocks), if you don't put a barrier strip on the bottom to free the cured Sikaflex, it will pull apart and get full of cracks and be next to useless. (I've routed out my share of Sikaflex from between deck seams, too!)

    If you want the white stips, epoxy them in place as described above. Finish bright as described above. If you are not planning to finish the deck bright (and I assume it is meant to be, since it is mahogany), then just tape the seam edges and use a good compound like Teak Systems for filling the seams. Sikaflex will not hold up as deck seam material. No way, no how. (Now watch somebody that did it last year and says his looks just fine... give it about three or four...)

    When you read these posts, keep in mind that there is usually a right way to do something and then there are all the ways folks who are trying to figure it out think up so they can have something to post. If you read between the lines, you can see who's talking from experience and who's just killing time at the scuttlebutt.

  19. #19
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    They are similar and also different.
    Permaflex is actually a harder substance than 5200
    and cures shiny. It is also a thick liquid like paint.
    I was also thinking there ought to be supplier of a liquid polyurethane industrial pipe and tank coating available in your area.
    Here is another contact company for liquid coatings, so it is not anything special just to sanitred. Perhaps you can email them and see if they can point you to a local supplier.

    http://www.madisonchemical.com/

    I think the liquidness of the material would be good in helping it flow into the gaps and fully saturating the seams. That is one other difference between permaflex and 5200. I wonder if anyone has ever tried to thin out 5200 and make it more like a paint. Part of what makes the permaflex so usefull to me is being a liquid, I can paint it on and know it seeps into cracks and crevices that 5200 would not reach. Just imagine a material that fills and seeps into cracks, crevices, holes and sets up as a hard rubbery coating bonding everything together in a rubbery matrix and youve got it.

  20. #20
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    ....That technique is used on finely finished, varnished decks and hatches on runabouts and such, not meant for much walking on. Is this the situation with your boat, or are these regular decks that some idiot put wood strips into instead of seam compound ....
    The deck on my 32 ft motor-cruiser is exactly how you describe it. It is there mainly for the good looks, and a nice V-berth underneath it too.

    Thanks for letting me in on the down-side of Sikaflex. The main cabin fore-windows that make contact with this deck were set with Sikaflex (around the perimeter) in 1998 and they were a real sod to take off. But I suppose Sikaflex can also shrivel up when left in seams on hot-decks.

    BTW, whose seam compound is the best ? The deck-to-gunwale seams need redoing with something other than epoxy. As I routed out the old epoxy to a depth of 6 mm on the latter seam, a (gaping) crevice of 2-3 mm came to light.

  21. #21
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    I'm with Gary E and Cleek. I did my cokpit coaming the same way, holding up fine. Use 2 part pourable polysulfide, (I used Boatlife).
    Also, as all the materials in epoxy are intended to be a part of the cured product, and not evaporate away, I feel acetone in the epoxy is not a good idea.

  22. #22
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    I have not used Boatlifeīs 2-part pourable polysulfideseam compound, but would not use their 1-part polysulfide again.

  23. #23
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    I've had excellent results with Teak Systems seam compound. For small jobs, it comes in caulking gun tubes... expensive at about ten bucks a tube, but I've had excellent results in about five years of use. Others told me the same. Given the work it takes to reef and refill seams, there's no point in using the cheapest stuff. Do put down a bond breaker in the bottom of the seam, though. You want it to stay stuck to the sides of the seam. If it sticks to the bottom, when the wood moves, it won't stretch like it should between the seam sides, but will pull away from the wood. If you can't find skinny bond breaking tape, even a layer of caulking cotton will do the trick just fine. (This is one reason people find that traditionally caulked decks aren't as prone to leaking.)

  24. #24
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    Carioca, Iīm trying to figure out why you want to put the wood strips in the seams. My conclusion is that it is only because that is the way the seams were done before...and the deck looked nice. That is why, right?

    You said they did not hold out, but you did not tell us why. What happened with the strips? What ever happened, it is going to happen again, unless you do something differently. (Probably the strips were splitting, and now you want to prevent it by making the seams more flexible).

    Unfortunately, it is not going to succeed because flexible seam compounds do not work in your type of installation. You have to fill the whole width of the seam with the compound in order to make it work. A thin film of Sikaflex between the strip and the plank will have to stretch by more than a 100 per cent, because the seam width will move between zero and, say, 0,5 mm according to seasonal change in the plankīs moisture content. That depends also on the plank width; a wide plank will move more than a narrow one. It will also depend on the grain direction in the planks.

    Most of the seam compounds are designed to stretch 10 to 15%, and some of them are capable of 30%. You are asking them to do a 100% or more. It doesnīt help to make the strip triangular, because at deck surface level there will still be almost no seam compound to stretch.

    It is an interesting challenge to try to explain in a concise manner how these elastomers work. I donīt claim to be an expert in the field; I have only done my share of deck and other seams. It is still true, I think, that next to alcohol, Sikaflex is the most widely misused stuff in boats.

    So Carioca, like almost everybody here has said, you are not going to gain anything by using Sikaflex or anything like that in your particular application. If you want to use the wood strips, you have to glue them in, and you have to paint or varnish the deck inside and out in order to minimize wood movement.

    The other approach is to forget about the strips and fill the seams with something flexible. If you ask me, my first choice would be a two part polysulfide like Smithīs, or Saba, or Formflex. Next come good polyurethanes like Sikaflex 290 DC or high quality silicone sealants like e.g. General Electricīs Silpruf. What ever you use you have to bear in mind that these elastomers were originally designed for construction applications with seams 15 to 20 mm wide and 10 to 15 mm deep. Any manufacturer will tell you that the minimum recommended is 6 by 6 mm. There simply must be enough of the stuff in the seam in order for it to stretch without stressing the glue line too much.

  25. #25
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    Jorma,

    I was scratching my head about what I should elect to do ......epoxy or sikaflex ...or even seam compound ? .....when your message arrived and broke the ice !

    The white strips that I weeded out last weekend were inlaid into the new mahogany deck in 1998, and some relevant deck data follow :

    1. Fore deck dimensions: 2,20 metres wide at base with king-plank some 2,10 metres long; I took a picture on Sunday but with SonyImage Station not honouring its obligation with WBF forumites etc etc ..... . Deck also has a hatch some 70 cms x 70 cms.

    2. There are some 8-10 deck beams, spaced some some 25 cms from each other in the above area

    3. New mahogany planks were affixed on the above deck beams with screws (fasteners) in 1998; the planks were 10 cms wide and 15 mm thick, and as they nudged against each other - and epoxy-glue was used to glue them together - they created a 5 mm x 5mm space for installing white-wood strips. Another 5mm x 5mm channel was also routed into the centre of the 10 cm wide plank so there are 2 (two) white-wood strips every 10 cms, one embedded into solid plank, the other in the nudging region between planks. and of course, miraculous epoxy-glue throughout .

    4. The leaks developed around the mid-deck area, specifically, over the king-plank and central-deck area, and also where the new deck meets the gunwales. Water would seep through minute cracks in the white-wood strips embedded with epoxy-glue in the region between deck-planks - I am only guessing - and drop onto the white-wood ceiling in the V-berth directly underneath . The port and starboard areas of this ceiling got the worst of it, due specially to the leaking deck-to-gunwale seams - plus gravity and water finding its way to the lowest level.

    A friend who visited me at the boat hangar last Sunday said exactly what you said in your message above - not enough room between white-wood strips (7mm x 5mm) and substrate (5/16" x 5mm) to create a Sikaflex bond, even if I did sculpture the former to a V X-section.

    He said to forget the white-wood strips and drop in seam compound.

    I need to solve this problem .......forever or as long as I live, because it would be a pain in the neck to go through the same rigmarole in the next 5-10 years or so.

    May want to turn to plastic and forget wood

  26. #26
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    I am getting ready to lay a complete deck on my boat, and internally coat 1,500 litros worth of fuel and water tanks. I had the Scuna rep here today, from Rio. He had samples of 6 different products that they carry. The thin product being something similar to what the guys here call cps..... something. Water being 1.0 the epoxy is not thinned and has a viscosity of 1.3. Darn close to water. The rest of their products fit almost every need that pooped into my mind.
    If you decide to call Scuna, you can talk to Leonardo and probably get an answer to almost any question a person might have about epoxy.
    Gerald

  27. #27
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    I will be adding color to the epoxy for a black joint. Po xadras works just great and as I am sure you know comes in many colors or mix basic colors to get any color you want.
    Gerald

  28. #28
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    Carioca, from your last post we learn that in the middle of the plank there is another wood strip (like a fake seam). Obviously, you have not routed out that strip. If you now do the real seams with a black seam compound, you end up with a pretty colourful foredeck. Maybe you have to consider replacing those remaining strips with the seam compound, too?

    To complicate things further, you have to consider varnishing the deck. Certainly mahogany will turn nicely gray exactly like teak, but I suspect that it doesnīt like to stay that way. Somebody here surely knows more about mahogany than I do, but my guess is that you should varnish the deck. If so, then you have to take into consideration that with time, the varnish will harden and start crumbling on top of the seam compound, thanks to the ever so small movements of the seams. Not a terribly big deal, but it will somewhat complicate the revarnishing you are going to do once or twice a year, or maybe even more often, considering your location.

    By the way, Iīm starting to suspect that you have been skipping varnishing the deck. If that is the case, we might be back in square one. Somebody earlier pointed out that your type of deck must be kept well varnished in order to keep wood movement to a minimum, and to seal eventual checks with fresh and soft varnish.

  29. #29
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    Yes, mahogany cannot be left unfinished. It will weather and eventually erode. While greyed mahogany does look like teak at one point, it doesn't last like teak. Mahogany decks are finished bright. Jorma's right about the varnishing problems with soft seam compound. The traditional mahogany decks had either a holly strip glued in over the seams, or white lead putty, which will harden fairly well and hold varnish better than any soft polysulfide.

  30. #30
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    Carioca,

    From what you said about the deck construction...
    2. There are some 8-10 deck beams, spaced some some 25 cms from each other in the above area

    3. New mahogany planks were affixed on the above deck beams with screws (fasteners) in 1998; the planks were 10 cms wide and 15 mm thick
    Supports spaced at 25cm or aprox 10 inches
    Deck boards aprox 15mm thick or aprox 5/8 inches
    Deck boards aprox 10cm wide or 4 inches

    This may not please you but I am going to say that this is sorta on the skimpy side unless you are a very lightweight fellow. The reason I say this is that stepping in the middle of the supports will allow the 15mm thick deck boards to deflect, they sure as hell would if I stepped there. That deflection will cause whatever you place in the seam to move and eventually leak.

    If that was my deck, here is what I would do. Mind you I think pretty is NO LEAKS, Can TAKE a BEATING and keep on keep on KEEPING THE WATER OUTSIDE..For example, in a rough sea, I can count on dropping the anchor and chain on the deck while getting tossed around, I am not gentile, and dont want to baby it, that deck must not dent, bust, or rust.

    Which brings me to what I would do...
    Fill the slots with a 2 part rubbery compound, forgit the white wood, or use the Caulk from Sanitred and then cover the intire deck with the sanitred paint on waterprofing.
    http://www.sanitred.com/

    If that is not to your liking, then I am afraid that the deflection that will happen will never allow that deck to remain waterproof UNLESS additional supports are added UNDER the deck between the ones you have now. That is a big job, one I would not do.

    If you can not get sanitred in your country, I would look to the rubber roof coating or tank lining industry for a product.

    Good luck

    [ 10-05-2005, 08:41 PM: Message edited by: Gary E ]

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    Location
    Rio de Janeiro, BRAZIL
    Posts
    3,865

    Post

    Gerald,
    If you have Scunaīs tel. number, kindly forward it to me.
    Actually I bought a litreīs worth of Tubolitīs laminating epoxy, a product that George (from Angra) had recommended a couple of months ago, when he also added that the proprietor is a chem. eng and pretty accessible too. I may give this guy a ring too.
    I am still wary about installing those white-strips with epoxy , though.

    Jorma,
    What I failed to add in my account above of the deck is that after it was first built (1998), the whole lot was sanded down and given around 4-coats of the finest 2-part clear polyurethane.
    When the first leaks came to my notice in 2000, I combed the deck area to see if I could identify white-strips that seemed unfirm in the mahogany substrate - and I did ! I injected 2-part epoxy into and around these armed with a docīs syringe and needle, sanded the deck with 120 wet-and-dry and then a couple of coats of 2-part clear polyurethane. Worked well for some time but leaked again - the latter got worse in terms of intensity, as the boat sat out in the water
    Yes, I have routed out ALL the white-wood strips, both over the plank-joints as well as in the plank centres. Must look homogenous, at least . Wish I could post a picture for all to see.

    Bob Cleek,
    Talking of varnish on mahogany decks, would varnish fare better than, say, 2-part clear polyurethane ? I mean in terms of durability, holding the whole lot together in the face of load-induced flexing etc etc ?

    Gary E,
    Yours was a good and succint acccount on how decks were built at Egg Harbour in days gone by.
    As for my current deck, we did think of reinforcing the deck-beams, but that would entail taking off the ceiling-lining, the port and starboard lockers etc... quite a big job, specially as we are looking forward to being able to avail of the boat this summer... The boat carpenter did his eye-ball-cum-foot testing and concluded that it would be overkill to do so.
    If I had to lay Sanitred or another opaque (industrial) liquid polyurethane on the deck surface, it would kill the good looks - but probably solve the problem !

    I shall contact Tubolitīs chem.eng. proprietor tomorrow, though I do not expect him to admit that epoxy will eventually crack if used in the contruction of a wooden deck like mine

  32. #32
    Join Date
    Feb 2000
    Location
    San Francisco Bay
    Posts
    11,207

    Post

    Varnish is much better than polyurethane. Polyurethanes do last longer than varnish and if applied correctly (which can be tricky) look very good. The catch, however, is that when they do break down inevitably, they are extremely difficult to remove and you end up practically having to grind them off. The best claim to last five years and probably do. In the end, though, most everyone I know who has tried them has gone back to varnish, which is easily maintained with a new coat over a light sanding every six months or so.

  33. #33
    Join Date
    Jun 2003
    Location
    Florianopolis - SC Brasil
    Posts
    641

    Post

    The site for Scuna is.......

    http://www.tubolit.com.br/

    The phone number etc. is in the within the site.
    Gerald

  34. #34
    Join Date
    Mar 2004
    Location
    Rhode Island
    Posts
    72

    Post

    Originally posted by carioca1232001:
    sdowney717 welcome on board and thank you for the tip. Sanitred, a polyurethane - and not a polysulfide , which I have had dismal results with - does seem promising, especially the high-UV formulation. Yes, the slots in my mahogany decking have been bared to raw wood, and the white-strips are newly cut but dried marfim wood.

    Sanitred does seem to have worked wonders on your restoration as per your account. But as it is unavailable in Brazil, DHL or Fed Ex will charge me at least US$ 300 just for shipping and customs-clearing fees. Plus cost of purchase + customs fees.
    If shipping is the issue,
    System Three Standard Resins and Hardeners are non-hazmat, so there would not be a huge shipping/customs fee. Just my $0.02

  35. #35
    Join Date
    Apr 2003
    Location
    Portland, OR
    Posts
    84

    Post

    Hazmat is not the issue with Brazil. Shipping costs are 2x normal, 20% VAT taxes and additional duties charged by their government are the main problem. A quart of anything imported from the US can quickly add up to $500.

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