Hollow Mast Wood

Thanks I hope so. I'm putting a lot of thought into the design features.

She will be Schooner Rigged and sails will be made with natural canvas color, 7oz Oceananus Ships Cloth in 18" wide panels like the cotton sails were made.
Oceananus is a Dacron fabric but looks and feels like cotton Sail Cloth. It's quiet like canvas too, doesn't sound like Dacron sail fabric.

It will work for the Narai because the Wharram Wing sail is flat cut & low aspect ratio.

While I'm describing her... She will have black hulls, read bottom paint, hatch covers, cross beams, masts, gaffs, cabin sides & tops, bulwarks will be bright finished and deck slats will be oiled Monkeypod. The actual deck will be painted.

Cheers, Allen

 

I will keep that cloth in mind. Your boat sounds lovely. The black and red plus bright work should go very well with those woods and those designs, and your island.

p.s. We will all have to visit when you are done. Reciprocal of course.
Everyone wants to come here for our 3 weeks of summer, ( as long as you don't mind fog.) ;-)

 

Would be fun.
It's North Sails that makes Oceananus Ships Cloth. It was kind of interesting how they came to make it. They have the story on their web site.

http://www.northcloth.northsails.com/Product/OceanusCloth/tabid/579/Default.aspx

Cheers, Allen

 

The rabbets help keep things aligned during assembly and aren't really necessary other wise. The last one I did didn't have the rabbets, because I used a jig.

I wouldn't use a cloth on the inside of the mast and only on the outside i areas where high wear might occur, such as where a gaff jaw might land (for example). I would use a generous coating of epoxy and of course internal reinforcements (swallow tails) at key locations, such as the gooseneck or spreaders. If you have any significant internal stresses in the staves that cause checking, a light fabric isn't going to do anything except delaminate. If you apply enough fabric to prevent a serious check, you'll really jack the spar weight.

Oceanus is nice stuff, but tends to be pretty heavy, compared to Dacron.

 

Yea that would be a pain if put glass on inside of mast & it delaminaed in places. Catch moisture bad then. So will go with good coat of epoxy.

The lightest weight Oceananus is 7oz, planning on using it. Hopefully it will be a good weight for Narai.

Cheers, Allen

 

That would be a pain in the glass. ;-)

 

3 coats of straight epoxy on the inside, would be the minimum to insure waterproofing.

 

Would you use additives for your final joining? Silica with a little talc to help break it up or something else? How thick?

 

On a wooden mast I would wet the faying surfaces with straight coat, pushing it in good, probably with a roller, just to be able to cover lots of area quickly, knowing the roller will waste a bit of resin. The thickened goo, is applied immediately after and would typically be fine milled fibers, some wood flour and silica to control viscosity. A lot of folks will just use silica, which works, but I've found you want some more elongation properties with spars, so wood flour and milled fibers can improve this. I wouldn't use talc, as this is just going to help smooth it out and add bulk, which isn't necessary inside a mast.

I glue the pieces with a big enough bead of thickened goo to insure some ooze out when I clamp the pieces together (this is what the small finish nails in the previously posted drawing do). I spread the ooze out, usually with my finger on small spars, to make a small fillet on the inside of the stick. You don't have to go nuts with this, though I admit to having mixed up more thickened goo, to fill in any gaps in the fillets I might have made. I do try to fillet internal reinforcements with a small transition from stave side to swallow tail, though couldn't tell you if this is worthwhile. I do it more to have no hard edges to catch condensation from running down, when the spar is upright and cooking in the sun.

I don't bother much with the outside of the stick, until it's fully assembled and the rounding process if nearly completed. This is when I touch up any gaps in the seams and these get knocked down with the final rounding and smoothing operations. Once it's rounded and smoothed to your liking, 3 coats of straight goo, before clear coating.

 

Excellent. Thanks PAR.

 

I hate douglas fir. I think you should use it so we run out of it that much sooner.

 

Another productive contrubution from Jammer, what a surprise. I see you still haven't been able to defend you previous comments, another surprise.

 

PAR, I was planning on using System Three Silvertip Gel Magic for all my 'gluing' wood together.

Actually what is the correct term for joining wood components with epoxy? It isn't called gluing is it, since it isn't glue, or is glue/gluing a correct term when using epoxy to bond pieces of wood together?

Anyway, System Three says Gel Magic is a thickened epoxy that doesn't need a coat of neat epoxy on both surfaces first and then a coat/layer of thickened epoxy.

Above you mentioned using a coat of neat epoxy then coat of epoxy with fine milled fibers, some wood flour and silica to control viscosity.

If I understand it correctly, the first coat of neat epoxy is to soak into the wood some, then the fine milled fibers and wood flour are to give the joints better elongation properties for the spars than just using one coat of Gel Magic on each surface only.

I decided to build the spars & gaffs with vertical grain D-F using the birdsmouth method.

So would it be better to use your above method for the spars & gaffs instead of Gel Magic. Which isn't a problem if it is a better joint.

Cheers, Allen

 

Depends on the application. Most of the time, it's laminating.

 

Actually, glues are made from natural products (milk, starch, rubber, etc.), while adhesives are man made (polymers, etc.). In reality, there's no practical difference with the terms, which are now interchangeable in conversation.

Epoxy is an adhesive and also a coating. System Three Silvertip Gel Magic is a thickened epoxy, though not in the traditional fashion, it still has bulking agents and viscosity modifiers, to permit it's use in vertical, overhead and fillet operations, without sagging. This is a premix formulation and not as economical as mixing your own, but can be a lot more reliable for the novice, particularly with consistency.

As to your question, it would be cheaper to use my method, but maybe easier to use the premix, if you're not very experienced with mixing goo. Most of us that use a fair bit of goo, don't want to buy different types for this and that, so we make up our own mixtures to suit the need.