Tuesday, August 18, 2015

Working on the mast for SEI

Beefing up the mast.

Chuck Leinweber at Duckworksmagazine.com has been using a woven fiberglass sleeve to reinforce the wooden masts he’s made for the various boats he’s built.
As far as I know he’s been using fairly cheap lumber for the birdsmouth system spars, and with the glass sleeve over them there has been no failures even when pushed very hard in events such as the Texas 200 and Everglades Challenge.

Here's his catalogue listing along with a little video showing how the 'glass sleeve is applied.


When visiting last year I had a look at what he’s done, looked over the material and decided that I’d give the stuff a try.  So, today, got the parcel out, sanded the mast blank off a little and got into it.

Its like a Chinese Finger Puzzle, push the ends together and it gets bigger in diameter, pull and it gets skinnier.  To apply, I shoved my hand down it while pushing the ends in, made it big enough to fit the mast through easily, and slid it through.  Taped the butt end to the wood and smoothed out the glass sleeve running my hands toward the other end making it smaller and a close fit as I went.

 I put a tape around the mast at the top end of the sleeve, this to provide a clean end to cut the strands of fiberglass to.  Next, I taped the end to the mast to control it while wetting out, and got into it with a brush and epoxy.

With two layers of gloves on, I smoothed the layup out, working from the start end up to the top of the mast pushing any bubbles out as I went.

This is fairly heavy fiberglass, and it soaks up quite a lot of resin, this 3.5m length took 300ml of resin. 
To see how the sleeve would work if I were to use Peel Ply or a similar substitute to control the resin content and finish, I wrapped plastic masking tape around the lower 800mm or so ( I ran out of tape)  and checked the rest to make sure it was properly wetted out.  I’m away for two days, and will pull the tape off when I get back so lets see how it comes out.

After all this was done, I was sitting on my bunk reading and sipping my mug of tea, watching this guy sitting on the end of my dock.  He or she is a Pied Shag, quite a big bird, similar to a Cormorant.  There are lots of them here as well as their cousins the "Little black shags" and the occasional King shag.  Its that time of year when the birds are seeking mates and making nests, so there is lots of interest and activity here on the river.  

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