Elliptical Carbon tube for booms

I’d like to get some elliptical ( or rectangular) carbon/graphite tube (about 4 x 10mm?) to make booms with scale looks on a small (victoria-size) sailboat. Does anyone know of a source, I’ve tried a few kite site with no luck. Airfoil-shaped should be fine too. The dimensions are more important.

thx

My local Hobby Store sells elliptical aluminum tubes in different sizes in the railroad section along with the metal sheets and the regular metal tubes and rods.
I actually used one for my Victoria jib until it broke during a “boat contact” at the mark.
It may work for you.

Gio

I considered aluminum tubes for the boom for a realistic look, since many booms on the big boats are made of aluminum too. Probably end caps made of shaped epoxy glue. The only problem is the sharp edges on any holes you make- cuts your string. But you could fix that by inserting plastic like wire insulation or something like that.

YOu could strengthen the tube by filling it with epoxy.

thx for the idea.

Tomo

I made some rectangular carbon booms.
I made an ali mandrel from 25 x 5 mm ali flat bar, tappering to 20 mm at one end for releasing purposes. Also pretty of releasing agent.
Using 2 layers of 25 mm carbon stock and some uni’s along the sides between the layers if the stocks.
Having problems uploading photos, will try later.

I could probably knock together a solid spar, about 4 x 8mm, but I’m trying to keep any extra weight to an absolute minimum, as this boat is only 0.9kg. Also, it would be easier to put the gooseneck fitting (ball link) into the end, although I haven’t decided on the design of the gooseneck yet.Maybe I’ll sway toward solid later.

cheers

I just tried an experiment with a 6mm carbon arrow shaft by inserting it into a close-fitting brass tube, then pressing tit between the jaws of my bench vise, while heating it slowly with my propane flame. Heat gun should probably work better, since you can set the temperature. I don’t know the correct temperature that will soften epoxy/carbon- I just guessed.

So after pressing the brass tube/carbon tube to an oval shape, I let it cool slowly, then I slit the brass open down its length and slid it off. So far the carbon tube has kept its shape. If it’s still good in the morning, I’ll make a full-length piece for the mainboom.