Would this wood work for cold mold?

Discussion in 'Boatbuilding' started by stonedpirate, Mar 11, 2012.

  1. stonedpirate
    Joined: Nov 2009
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    stonedpirate Senior Member


    I was thinking about ordering the below wood.


    My plan is to do a strip plank hull then double diagonal cold mold over the top.

    I will use that quick strip western red cedar for the strip plank layer, but do you think i could use it for the double diagonal layers?

    Or will that groove not match up around some bends in the hull?

    Bad idea?

    If so, what would be a better wood for the cold molding?

  2. Corley
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    Corley epoxy coated

    WRC is a good timber for cold molding. I'd question the value of using it in your application as a tongue and groove just a standard DAR style plank would probably do the job as well with less waste. The tongue and groove makes sense for long thin shapes like multihulls but less sense for very full hullshapes. Whatever type of strip plank you choose there will have to be "stealer" planks fitted to accomodate the changing curvature and fullness of the hull over its length.

    With cold molding a lot depends on how sharp the curves your trying to achieve are, if its a full shape with quite a gentle curve to the bilge you can go for thicker stock for hard turns to a bilge you may need thinner stock to make the curve. Keep in mind that tongue and groove strip plank wont be suitable for the outer diagonal veneers you'll need to spile veneers to fit the shape while maintaining an approximately similar angled fibre orientation with each adjacent veneer over the boats length.
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  3. Tad
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    Tad Boat Designer

    Western Red Cedar is what you want for strip-planking but the prices in the link are unbelievable.......$26.76 a board foot!!!.......around here we typically pay $3-5.00.......far better to set up a router and machine your own....or leave the strips square and fit with a sharp hand plane.......
  4. NoEyeDeer
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    NoEyeDeer Senior Member

    WRC is insanely expensive over here. Kiri (paulownia) would be a better choice.
  5. cthippo
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    cthippo Senior Member

    Look for a house being remodeled and ask for the wood they tore out. It will usually be better quality than what you can buy today, and it's free.
  6. Steve W
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    Steve W Senior Member

    When you cold mold over the strip planked layer you cant use tongue and groove strip, your cold mold veneers will be thinner than the strip planking and you will most likely need to fit the veneers to the previous one, its called spiling, when you lay on a veneer it will usually touch at the keel and gunwhale while being away in the middle so you need to spile it off the previous veneer, so even if you did have a tongue it would get cut off. Nothing wrong with the wrc but better to cut your own veneers. Ive never used the kiri but it looks like a good choice.What boat are you going to build?
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  7. rwatson
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    rwatson Senior Member

    You would need to watch the 'clearness' of the Kiri - as it is not quite so flexible as WRC since he is doing cold moulding.

    Any kind of edge moulding ( tounge and groove, curving ) would be a waste of time for cold moulding. You will be doing angled planks, and the edges will need to be planed to shape to meet the next plank properly.

    I would never consider doing cold molding with 'real wood' - its such a waste of expensive quality timber. Ply would be a better approach for cold moulding. Proper planking is the most attractive method if you want a bright finish.
    Last edited: Mar 16, 2012
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  8. Corley
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    Corley epoxy coated

    The kiri veneers I've used are thicknessed down from venetian blind style slats so not much waste there but your mileage will vary depending on what your source stock is. WRC is nicer to use as an external veneer as it seems to crush less than the kiri and bends just a bit more nicely it also seems to hold staples better in my case I've often found I have to staple right through to the base mold to get the staples to hold on heavily curved sections.

    I strongly considered doing a WRC lamination as the final veneer on my build but decided light weight was most important and I'll use a sheathing of glass and paint. I guess everyone has their own aesthetic sense because I quite like the look of the diagonal veneers clear finished some people run the final veneers fore and aft to achieve the planked look.
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