what to do with the deck.

Discussion in 'Boat Design' started by whitepointer23, Dec 30, 2014.

  1. PAR
    Joined: Nov 2003
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    PAR Yacht Designer/Builder

    Oregon isn't the best decking material, just not dense enough to work well, unless old growth and heartwood only.

    Xynole and Dynel are different materials and have different properties, with Xynole being far superior in every regard. Typically with cloth, the weight of the cloth is the amount of goo you'll need to wet it out. Double this, plus a bit more for these other fabrics.
     
  2. whitepointer23

    whitepointer23 Previous Member

    The bowsprit is oregon . The deck is hardwood. I will find the local supplier for xynole. Thanks .
     
  3. Steve W
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    Steve W Senior Member

    Par, you really like that xynole don't you, one of these days i will have to try it. We used a lot of dynel back in the 70s down under
     
  4. Steve W
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    Steve W Senior Member

    Oops, i accidently posted before i was finished. Back in the 70s when we were building a lot of cold molded boats dynel was very popular for sheathing everything and i love the stuff, ive been aware of xynole forever but have never explored it at all but will do so at some point when i have a project to use it on. I know dynel is available down under but im not so sure about xynole.

    Steve.
     
  5. PAR
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    PAR Yacht Designer/Builder

    It's simple math Steve, Xynole is about 3 times better at abrasion than Dynel, costs the same and uses slightly less goo (still much more than 'glass cloth). Plus, though I haven't got really good testing, others have some and it's peel strength is in question. In most applications, this probably isn't an issue, but it's (and the math) gotten me off the Dynel band wagon.
     
  6. whitepointer23

    whitepointer23 Previous Member

    Par is xynole known by any other name like a brand or something. I have not found anyone here that lists it yet.
     
  7. waikikin
    Joined: Jan 2006
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    waikikin Senior Member

    acrylic v polyester?

    I've never seen it here(ever, in decades), of course we might have bought xynole as dynel & not known or worried anyway... but I found these quotes below over at woodenboat forum, interesting like many things.. & attitudes to pricing, I'm happy to pay a markup if I don't have to hold bulk stock, similar margins apply on choppy etc at retail.;
    "When I contacted Southern Industrial Fabrics and asked about the Xynole they supply to Defender Industries they told me:


    Per you request for the Xynole product we don't call it by that name. I can only assume it would be our modacrylic fabric we sell to Defender. We also supply them a polyester so I don't know which item it is exactly.So I went back to the Defender web site and got the detailed info for these fabrics and sent it all to Southern Industrial. They confirmed that the modacrylic they sell to Defender is Dynel and the Xynole is polyester. Surprisingly they also told me they will sell me 3000 yards (their minimum order) of the polyester for only $2.15 a yard ... :eek:

    Yes, this is the very same fabric Defender brands as "Xynole" and resells to boat builders in small quantities for $8.95 a yard!"

    Well I went out and bought myself some xynole from Defender, to see for myself was this mystery fabric was. I mean really, what is this fabric that is only available from only two sources in world, and that no textile manufacture anywhere makes?Of course a textile maker manufactures it! It's made right there in the USA as a matter of fact.


    My next step was to bring my sample around to a friend of mine who works in the textile business. Despite being in the business for almost twenty years he had never heard of xynole ...No surprise to me. When I contacted the manufacturer they didn't know what the term "Xynole" referred to either. After I told them Defender buys it from them, they said Defender buys only two fabrics from them, and from my description they figured out which one it was -- the polyester fabric, not the other one (Dynel) which is a combination of two different types of plastic threads.

    They gave me their product number for what the boating industry calls Xynole so I wouldn't cause any more confusion by calling it Xynole when talking to them about it. They will make it and sell it to anyone of course, you just have to buy a HUGE roll (or multiple rolls) of the stuff.


    So it turns out that xynole also goes by the less sexy name of "polyester".Exactly. Polyester comes in a wide variety of weaves too, so it would make sense to know the correct Xynole weave, thread count, etc. before using just any old generic polyester fabric. Open weave is critical for any Xynole substitute though ...


    ... and FYI Dynel is acrylic ...Dynel is actually a combination fabric made with polyester and acrylic, or acrylic and olefin, or two other plastic fibers -- I just don't recall which ones at the moment. That's what I get for growing old, I can't recall all my facts as quickly as I used to ... :(


    I agree that it is most likely made for some general purpose which has been marked up for the boat industry, but the actual cost of it and its other properties are much harder to nail down.In Asia the cost of bulk commodity fabrics like fiberglass and polyester are based on material weight, with adjustments made for the extra cost of certain types of weaves. You can pretty much count on the fact that a plain weave will cost roughly $X.XX per kilogram from nearly all suppliers, and satin weave $Y.YY, and herringbone weave $Z.ZZ for example.


    Keep in mind that some peel-ply fabrics are also polyester and used as such because epoxy will not stick to them.Let's not forget that one of the other critically important features of peel-ply which makes it work the way it does (in addition to the fact that it is polyester) is the fact that it is a very tight weave material which is very effective at preventing epoxy from getting in between the woven threads. My personal belief is that it's the tight weave that results in so little epoxy gets in between these threads, and this means the fabric is stronger than the epoxy in this area -- and that's why the epoxy rips apart rather than the peel-ply when you try to remove the peel-ply.

    On the other hand, Xynole is such an open weave that plenty of epoxy gets in between the threads. Wth so much more epoxy bonding in between the threads, the epoxy ends up being stronger than the Xynole when you try to peel it off. I believe that any time the epoxy is stronger than the fabric, it's the fabric that will fail when you try to peel it off, not the epoxy. Open weave won't peel off, but closed weave will. That's about the size of it.


    It's certainly worth doing some adhesion, compatibility and tear strength testing with some promising-looking potential substitutes and comparing them to actual Xynole in the same tests, but just because it's polyester doesn't mean that it will work.The cheap closed weave polyester I bought in the local fabric store for 20 cents a square meter certainly works great as peel ply!

    I bought some open weave polyester to try as a Xynole substitute too but I haven't used it yet, so my personal tests have yet to be commenced. Unfortunately I couldn't compare generic open weave polyester to Xynole anyways since I have no "Xynole" ... but I don't think a direct comparison is necessary anyways. If I cannot peel off the generic stuff then it will work fine as a Xynole substitute in terms of waterproofing and abrasion resistance -- and that's all Xynole is normally used for anyways."
     
  8. Steve W
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    Steve W Senior Member

    That's some nice sleuth work there. You can almost always bypass the distributors and buy your materials for a fraction of the cost if you can purchase a large enough quantity. When I used to manufacture snowboards we bought epoxy by the drum and triaxial glass by the pallet direct from the manufacturer but if i need to buy by the yard then I don't mind paying an up charge as long as someone stocks it. What I object to is non stocking distributors getting a mark up.

    Steve.
     
  9. PAR
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    PAR Yacht Designer/Builder

    Yep, Xynole is a polyester, but it's fluffy, not sized and finished, like other polyester fabric threads and strands, which allows it to absorb epoxy. It doesn't absorb quite as much, comparatively as the modacrylic (Dynel), which is also a fairly unfinished thread. I know that Union Carbide is the original manufacture for Dynel, but I don't know if they sold rights or have production arrangements with other manufactures.

    5 ounce (170 gsm) Dynel is about $12 retail. 8 ounce (270 gsm) Xynole is about $8.75 retail. Xynole has good impact and abrasion resistance and about the same "drape" as Dynel, which has better tensile qualities, but not as much impact or peel strength, hence my general recommendation for Xynole.
     
  10. whitepointer23

    whitepointer23 Previous Member

    excellent reply jeff . you should have been a detectective.:)
     
  11. whitepointer23

    whitepointer23 Previous Member

    i spent today cleaning the cabin and removing flaking paint. looking at the amount of work the deck needs i am leaning towards ripping it all up and replacing with ply. the good news is all the deck beams i have looked at so far are in really good condition. question 1. can i just sheet the deck with 1 layer of ply with butt block joints. q2. can i get away with just painting the deck with quality marine paint instead of epoxy. q3. are decks laid and toe rails fitted after or do the planks butt up to the toe rail. i have only had commercial plank boats before with out toe rails. q4. in 1st pic you can see 2 plugs in toe rail so i am guessing it can be removed while i do the work, is this correct. thanks in advance.
     

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  12. michael pierzga
    Joined: Dec 2008
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    michael pierzga Senior Member

    From the pictures it looks like a steel boat ? Corrosion on top of the frames could be an issue. Have good look before you proceed
     
  13. whitepointer23

    whitepointer23 Previous Member

    its all wood micheal.
     
  14. michael pierzga
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    michael pierzga Senior Member

    Now I see.

    Ply with butt blocks will work. After the butt has cured grind out the top joint and lay in double biax tape. This will keep the joint from printing thru.

    Hard to keep mechanical fasteners from printing thru. A laminated ...two ply deck... prevents this

    A two ply deck might improve the deck sheer clamp interface.
     

  15. whitepointer23

    whitepointer23 Previous Member

    can you explain this to me please.
     
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