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Thread: Bedding compound

  1. #1
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    Default Bedding compound

    So after thinking of using plain roofing tar and felt to join my stem pieces together, the suggestion of 3M 5200 came up. I can get it at a local hardware store but a little more research amongst your fine forum posts of the past and I am beginning to doubt that as well..... What is suggested in a traditionally built stem? Dolphinite seems unavailable in Canada, 5200 is too permanent and roofing tar seems to me that it will be a sloppy mess. Bob talks of plumbers putty at $3 a tube. Vulcanite I think he recommended. Is that where I should be looking at this point? Thanks guys,
    Daniel
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
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  2. #2
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    Default Re: Bedding compound

    What kind of boat? You did not mention cotton, so

    Besides Dolphinite (try Dolphin 3400 or 3401), Boatlife LifeCaulk, Sikaflex, 3m 4200. On small boats my habit is LifeCaulk.

  3. #3
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    Default Re: Bedding compound

    Catspaw dinghy with a traditional made stem. A stem, a knee and a gripe with stopwaters, all bolted together with bronze bolts. I plan to build her riveted lapstrake construction. I guess I'm not committed yet at this point but I'd like to build a traditional boat in a traditional manner, just so I can say I've done it and this boat seems a suitable one to try on. The stem material is Black Locust and planking will be some form of cedar, WRC is possible. I'd like it to be a traditional bedding compound but if a modern goop has all the good qualities of a traditional product and more, I have no problem using a modern goop but I think being able to disassemble it at some point in the future is important in this type of boat that will likely need repair at some point down the road.
    Last edited by Sailor; 02-17-2017 at 07:16 AM.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
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  4. #4
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    Default Re: Bedding compound

    Butyl rubber perhaps, applied thinly and warm on warm wood as you bolt it together. You can get it cheap at Home Hardware.

    I used it as deck fittings bedding on Drake. Sticky, and doesn't harden.

  5. #5
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    Default Re: Bedding compound

    Permatex form-a-gasket is a mix of clay, oil and rosin, which is pretty close to Dolfinite. #2 sets up firm, almost hard, but not brittle. The #3 stays soft. Both can be cleaned up with alcohol. #3 has a 'Canada part number' under the picture in the link. #2 does not. If #3 is thinner than you want and #2 is not available in Canada, you can thicken #3 with any of the usual powdered fillers, even finely ground clumping cat litter (bentonite). After thickening the permatex, you can always use the rest of the cat litter for making green sand or, in a pinch, you could put it in a litter box.

    https://www.permatex.com/products/ga...-no-2-sealant/
    https://www.permatex.com/products/ga...ealant-liquid/

    5200 is too permanent? Who takes a stem apart?
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  6. #6
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    Default Re: Bedding compound

    I'm not hoping to ever have to take the stem apart. It's Black Locust and won't sit on a mooring anyway but I still think if I'm going to build traditionally, I should use traditional materials. Otherwise, I can't say I built her traditionally. Maybe 5200 is the way to go. I don't know. If I can get the same results for much cheaper, I'll go the cheaper route. Just trying to do my due diligence here so I do the best job possible with my likely less than average skillsets.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

  7. #7
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    Default Re: Bedding compound

    Don't confuse roofing tar with roofing cement, which might be a viable candidate for your project. At $4/tube you need some around the house anyway; Tremco Instant Patch is the best of the best, for the bucks.

    Premixed!! / Jim

  8. #8
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    Default Re: Bedding compound

    I've got a 5 gallon bucket of roofing tar in the barn already. Just seems like it would be pretty messy one a hot day. Once built and painted (likely white) would the tar forevermore be contained?
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
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  9. #9
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    Default Re: Bedding compound

    Not alone under white paint, nor would I recommend it for exposed locations. It doesn't run in the heat, after all it designed for rooftop flashings, but it softens somewhat. I sometimes use it to bed down through bolted items but I clean up squeeze-out and use a paint friendly caulk at the edges.

    Again, roofing cement is not roofing tar, in my world. / Jim

  10. #10
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    Default Re: Bedding compound

    What's the difference between roofing tar and roofing cement? I've used a roofing tar product that had a granular feel to it and I have a big bucket of tar that does not. Is that the difference in the products that you're referring to?
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

  11. #11
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    Default Re: Bedding compound

    I've never tried it, but have often thought that it would be quite effective to thin linseed oil base window putty with clear Cuprinol (zinc napthanate) to use as a bedding compound that will be long lasting and help prevent rot.

  12. #12
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    Default Re: Bedding compound

    Dolfinite (Dolphin) and things like it are a PITA because they tend to bleed and run for some time. Check out sources for Boatlife or Sika. There is construction grade Sika which may very nearly be the same thing but seems not to handle as well as the marine grade.

  13. #13
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    Default Re: Bedding compound

    "What's the difference between roofing tar and roofing cement?"

    Four bucks the next time you pass Home Hardware will give you the best answer to that. And much quicker than I could define and defend here.

    I have had failures with Boatlife and Sika 291 that involve applications to raw or oiled wood. My current boat caulk is 3m 4200, but the dark colour seems prone to drying out and cracking also. Good luck! / Jim

  14. #14
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    Default Re: Bedding compound

    Quote Originally Posted by Sailor View Post
    I'm not hoping to ever have to take the stem apart. It's Black Locust and won't sit on a mooring anyway but I still think if I'm going to build traditionally, I should use traditional materials. Otherwise, I can't say I built her traditionally. Maybe 5200 is the way to go. I don't know. If I can get the same results for much cheaper, I'll go the cheaper route. Just trying to do my due diligence here so I do the best job possible with my likely less than average skillsets.
    Ah, tradition. No offense, the desire to build traditionally is perfectly reasonable.

    Dolphinite is a thin linseed oil(?) based putty with silica and mica powders as a filler. So rosin, castor oil and clay sounds traditional to me, even if it does come in a tube from an auto parts store. I can understand the desire to find a suitable ready mixed material. The pleasure of melting rosin and stirring in linseed oil and a bag of dust is lost on most people. A little zinc oxide filler and copper naphthenate solution as the thinner might be a good as they will reduce mildew on the caulk, but black locust probably doesn't need much help.

    According to a forum posting (I lost the link) Dolphinite is not sold in Canada because the label isn't bilingual.

    Roofing cement vs tar. According to the venerable boat building resource, the Chicago Tribune:
    To get the terminology right, coatings have the consistency of thick paint and are typically spread over the entire roof with a heavy-napped roller. Roof cement is a dense paste typically spread with a trowel that's used to spot-seal leaks.

    http://forum.woodenboat.com/showthre...dding-Compound
    http://forum.woodenboat.com/showthre...dding-compound
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  15. #15
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    Default Re: Bedding compound

    Quote Originally Posted by Sailor View Post
    Catspaw dinghy with a traditional made stem. A stem, a knee and a gripe with stopwaters, all bolted together with bronze bolts. I plan to build her riveted lapstrake construction. I guess I'm not committed yet at this point but I'd like to build a traditional boat in a traditional manner, just so I can say I've done it and this boat seems a suitable one to try on. The stem material is Black Locust and planking will be some form of cedar, WRC is possible. I'd like it to be a traditional bedding compound but if a modern goop has all the good qualities of a traditional product and more, I have no problem using a modern goop but I think being able to disassemble it at some point in the future is important in this type of boat that will likely need repair at some point down the road.
    To question a pretty major assumption that appears to be driving the main question of which bedding to use ... I can't see ever having to take the stem apart on a Catspaw dinghy. Over the years, I've run my little boats into lots of stuff ... reefs, pointy rocks (charted and uncharted), dolphin/piles, docks (metal and wood), other boats (apologies to Fire-Drake, Rowan, Bandwagon, etc), floating logs and flotsam ... and never had to take apart the stem.

    I've had to patch up little dings here and there. If you had major damage, you'd probably end up doing a dutchman to repair a ding or perhaps scarf in a new piece (but that scarfed piece is unlikely to be the same size/shape of the upper/lower stem pieces that you're currently installing). I don't think this is a question of bedding, but of which adhesive to use. Personally, I'd use thickened epoxy when assembling the stem and then seal everything up with paint.
    Last edited by Yeadon; 02-17-2017 at 03:14 PM. Reason: I had additional helpful and amazing things to say.
    Quote Originally Posted by James McMullen View Post
    Yeadon is right, of course.

  16. #16
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    Default Re: Bedding compound

    It is improbable in the extreme that you will ever replace the stem. You want a traditional cedar on oak build? I would keep the epoxy work to a minimum. Mixing small bits of epoxy is a pain in the ass. There are some places I use it in this kind of construction, but not for seating the planks. Give yourself a break and use one of the single part tube goos, even if the tubes are a little pricey. Hedge your bets - not something quite as aggressive as 5200. I'm sure you can find the current version of Dolfinite under the correct name if you insist. Or some similar store bought concoction as people have described.

    Admittedly I am used to paying deep discounts on marine supplies so may not appreciate how pricey some of this stuff can be. Convenience however is worth something.

  17. #17
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    Default Re: Bedding compound

    4200 is basically 5200 that can be disassembled.

  18. #18
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    Default Re: Bedding compound

    Just realized I jumped way ahead to planking. Stand by previous musings, but I also back up Tim's comment.
    The stem assembly itself for this kind of boat is one where I've increasingly gone to epoxy. But not with white oak, and only with parts whose dimensional stability I have faith in - which is not asking too much for something of Catspaw size. Stopwaters are eliminated.

  19. #19
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    Default Re: Bedding compound

    Quote Originally Posted by J.Madison View Post
    4200 is basically 5200 that can be disassembled.
    To be honest I practically never use either of them. 4200 sounds very much like some of the sikas.

  20. #20
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    Default Re: Bedding compound

    I have used 3M automotive caulking strips with great results. Even after 20-30 years when I have removed bits that were bedded with this it was still working, keeping the water out while remaining soft and pliable.
    I really like it, and use it primarily around stuffing boxes, through hull fittings etc.
    edit; You can get it anywhere.


  21. #21
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    Default Re: Bedding compound

    Here is a thorough tutorial on bedding with butyl tape:

    http://www.sailnet.com/forums/gear-m...utyl-tape.html

    At the end the author recommends Bed-It rather than 3M. They appear to be similarly priced, about $18 for 50 to 60', the biggest difference seems to be that Bed-it is in a continuous roll vs 3M which is in strips. Anyone here have opinions on which is "better"?

  22. #22
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    Default Re: Bedding compound

    Truly tradional construction, ........ With proper stopwaters you don't need anything.

    That aside, Given the available materials to choose from today (and lack of traditional materials) I think I quite like the idea of a little bit of Permatex #2 (the stay soft formula). I wish I had thought of that, I would have used in when I pulled and repaired my stem.






    Window glazing (regular "DAP 33") is something that I have used a bit and am not against, unfortunately it does dry out and harden up in a matter of months when in contact with bare wood.

  23. #23
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    Default Re: Bedding compound

    4200 is basically 5200 that can be disassembled.
    I used 4200 to bed a deck prism into Bucephalus's deck. I can vouch that a heat lamp above the prism and a bottle jack lifting from beneath did in fact enable disassembly after a couple hours of the heat-and-pressure treatment. It also convinced me that 5200 would be virtually impossible to break loose, and made me certain I'd never use it to "bed" anything, least of all wood.

    Gotta say, Sailor, with my current project of rebuilding a 125-year-old Cranberry Isles rowing skiff, where disassembling the stem *will* be part of the process, I'm with you 100% on your approach. If you can find it, my vote would be for Dolphinite. Maybe even worth a vacation up to Maine and a chandlery there. I've heard the new CAT ferry is a fast and fun trip...

    Alex

  24. #24
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    Default Re: Bedding compound

    I am beginning to feel I suffer from "analysis paralysis". I just need to go ahead and do it instead of digging around. There's more than one way to skin a cat and if I look around long enough, I'll find every single way to do it and still have an un-skinned cat. I have tar on hand and I think I'll just use plain old black roofing tar for it.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
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  25. #25
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    Default Re: Bedding compound

    Related "Arts and Recipes" thread:
    http://forum.woodenboat.com/showthre...x-rosin-filler
    Management is the art of counting beans. Leadership is the art of making every being count. --Joe Finch

  26. #26
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    Default Re: Bedding compound

    For whatever it's worth, I've added powdered cuprous oxide to canned bedding compounds. (Tar between the ballast and keel, Dolfinite inboard.) Because of the copper, I have huge confidence that the resultant compound will never allow rot. As I am in the middle of my build, I'd love to find a cheaper alternative than the canned compounds such as Dolfinite and Interlux - the tubed compounds won't work because I can't add the copper, and tar is too messy inboard. Cuprous oxide is available from ceramic supply outfits, but get the red, not the white.
    "Do not let schooling interfere with your education" M. Twain

  27. #27
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    Default Re: Bedding compound

    Found a proper tube of 5200 and that's the route I'm going. They also happened to have a nice bronze padeye for the bow. I just need to trim off a couple of the sticky outy parts and she'll fit nicely.
    If one advances confidently in the direction of his dreams, and endeavors to live the life which he has imagined, he will meet with a success unexpected in common hours.
    -Henry David Thoreau-

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