RE: [bolger] Re: alum. mast

There will never be a consensus on this issue. I had been in the encapsulation camp, but now am having my doubts. I have seen solid wood swell and tear 6 ounce fiberglass. (This was the rudder stock on my Birdwatcher. I put glass on the plywood sides and continued around the solid wood forward part.) Apparently, the water is still getting through. My latest, a Surf, has glass cloth and epoxy to protect the bottom from abrasion, but has no epoxy coating elsewhere. I built it this way to see how it holds up compared to my other boats.

Dave Carnell, with a lot of experience and a solid technical background, concluded that encapsulation was worse than worthless. See the last paragraph on the epoxy knowhow page here:http://www.angelfire.com/nc3/davecarnell/

The late Robb White, professional builder of some very attractive boats to his own designs, soaked everything in epoxy. His procedure was to heat up his whole shop and the assembled boat, then crank up the AC and coat everything with resin. As the wood cooled, the air contracting in the wood pores drew the resin into the wood. He used tulip poplar primarily. He would not build in plywood. Check out the boat porn here:http://www.robbwhite.com/boat.photos.html

For small boats, I suspect that glassing the bottom (for hard chine types) or the whole exterior (for stitch and glue) and storing it upside down is sufficient.

Doug

--- Inbolger@yahoogroups.com, "adkgoodboat" <masonsmith@...> wrote:
>
> Friends all, this talk of encapsulation of the inside of a birdsmouth mast has provoked me to start a new thread on encapsulation in general, and I hope we'll get the benefit of collective wisdom on the subject.
>

Friends all, this talk of encapsulation of the inside of a birdsmouth mast has provoked me to start a new thread on encapsulation in general, and I hope we'll get the benefit of collective wisdom on the subject.

Myself, after 23 years of building a cold-molded composite boat (building #68 now) and encapsulating pretty much everything, I am dropping the practice in many areas. I would now not epoxy coat the interior of a mast, or the exterior either. I'm not going to encapsulate my inwales/outwales, seat riser stringers, etc. etc. Just, in fact, the laminatted (constant camber) hull.

Some learnings: where solid parts which have been kiln dried, and even in some cases parts which have been air-dried, pick up some moisture and expand, they do so like frozen water in a crack in rock, with irresistible force, breaking hard coatings and bonds. Better let such things breathe, or not use solid wood.

--where encapsulated wales, rails,risers, etc, get bruised and the epoxy coating broken, moisture gets under the epoch and progressively separates the coating from the wood, and so on. Better put on a permeable finish which won't lift.

In this context, I recall John Gardner commenting on my practice on the Adirondack Goodboat, probably at a Small Craft Workshop at Mystic: coating the rails "might be all right. I wouldn't do it."

This proviso: edges of plywood, once terrible places for bad news to get started, are no more, thanks to epoxy. When they have been saturated and coated with epoxy, I venture to say they are the last places you need to worry about water penetration.

Another contrary point: In a recent WoodenBoat how-to series on building a small canoe, Nick Schade (I think it was) gave without comment a (to me) shockingly new set of directions for encapsulating wales and stringers: coat them, yes, and then coat them again and again with biaxially cut fiberblass! On Nick'sa brilliant Guillemot kayaks and canoes, you would not know this had been done, but I guess it's part of the secret of their beauty. I do think that if we glass out rails like that, they won't get banged up with the consequences mentioned above. But the practice has consequences for desigh (how rails are rounded over, what about rowlocks, etc.) and, well, I am not going to do it this time. Varnish only, this time, on the ash waled of the new goodboat.

I would also suggest we consult Trimaran Jim Brown, one of the most experienced epoxy-using boatbuilders I know. His own ordinary fir plywood Searunner Trimaran, Scrimshaw, built in a968 and 69, has no interior coating. It breathes. It has lived in the tropics, is now in Virginia. It is just about as good as new.

I think that birdsmouth mast rotted for other reasons than the lack of interior coating. What-say, all?

---Mason

P.S. I might mention too that the first Whalewatcher, sloppily built by somebody on the Chesapeake for George Anger, was boiling with rot when I got it, because somebody had coated the inside of the hull bottom, in the center, the standing room area, end to end, with epoxy and cloth. Once the rot got started in between the outer cloth and the inner cloth, it went wild. Following the grain of successive laminations of the plywood, it ran out to the sides, up the sides, up the walls of the ballast tanks, to the point where I, following the rot with a chainsaw and a skilsaw, gave up the notion of cutting out the rot and saving the hull, and took it to the dump.

Nice solution.=

Making a tapered mast from a couple 2x4's glued together is fast and
fun. Really. A few minutes to glue them together, wait overnight for the
glue to set up, then spend an afternoon planing, and then paint. There
is no better way to create long, lovely curls of wood (good as tinder
for your fireplace when you are tired of admiring them) with a block plane.

Patrick

Bruce Hallman wrote:

> On Thu, Jun 18, 2009 at 7:19 AM, mednak2000<dccrc@...> wrote:
>
>> IM BUILDING A BRICK/PDR,IM WONDERING IF ANY ONE HAS TRIED USING ALUM.TUBING
>> FOR A MAST.IF SO HOW EXPENSIVE WAS IT.IM GUESSING WOOD WOULD BE CHEAPER,BUT
>> ALUM MIGHT BE QUICKER.
>> DON
>>
>>
>
> When I priced it, aluminum tubing was far more expensive. If you want
> cheap and quick, go and cut down a small 3" diameter tree, like I did
> for my Teal. Or, you can use plain old lumber from Home Depot.
>

I agree. They aren't that hard to build and perform beautifully.=

THANKS FOR THE INFO.--- Inbolger@yahoogroups.com, Bruce Hallman <bruce@...> wrote:

>
> On Thu, Jun 18, 2009 at 7:19 AM, mednak2000<dccrc@...> wrote:
> >
> >
> > IM BUILDING A BRICK/PDR,IM WONDERING IF ANY ONE HAS TRIED USING ALUM.TUBING
> > FOR A MAST.IF SO HOW EXPENSIVE WAS IT.IM GUESSING WOOD WOULD BE CHEAPER,BUT
> > ALUM MIGHT BE QUICKER.
> > DON
> >
>
> When I priced it, aluminum tubing was far more expensive. If you want
> cheap and quick, go and cut down a small 3" diameter tree, like I did
> for my Teal. Or, you can use plain old lumber from Home Depot.
>

On Thu, Jun 18, 2009 at 7:19 AM, mednak2000<dccrc@...> wrote:

>
>
> IM BUILDING A BRICK/PDR,IM WONDERING IF ANY ONE HAS TRIED USING ALUM.TUBING
> FOR A MAST.IF SO HOW EXPENSIVE WAS IT.IM GUESSING WOOD WOULD BE CHEAPER,BUT
> ALUM MIGHT BE QUICKER.
> DON
>

When I priced it, aluminum tubing was far more expensive. If you want
cheap and quick, go and cut down a small 3" diameter tree, like I did
for my Teal. Or, you can use plain old lumber from Home Depot.

There is a PDRACER group here on Yahoo that may be an even better site for advice on variations to your PDR. Best wishes for a great result.

IM BUILDING A BRICK/PDR,IM WONDERING IF ANY ONE HAS TRIED USING ALUM.TUBING FOR A MAST.IF SO HOW EXPENSIVE WAS IT.IM GUESSING WOOD WOULD BE CHEAPER,BUT ALUM MIGHT BE QUICKER.
DON