hull construction

Ketil B · Post by **Ketil B** » 20 Jan 2004, 07:26

Hi all

I am just about to start building a new hull, and was thinking of making it with balsa wood plank covered with dope and tissue paper. A method is used in R/C aircraft construction.

I was wondering if any one has tried this and if they have how did it work out.

Thank in advance

Ketil

Roy Thompson · Post by **Roy Thompson** » 21 Jan 2004, 00:14

Whilst I have never completed a hull like that, I did do some tests with various weights of glass cloth and epoxy resin (as opposed to tissue) used with balsa to make a sandwich type hull. The problem I had with balsa is it tended to absorb lots of resin (heavy) so needed to be treated with a sealing agent first to avoid this. Even so, the final weight was almost identical to wood planked by the time I had put enough resin inside to waterproof it and a single layer of 165gm glass cloth outside to protect it. This was the other problem - balsa is relatively easily damaged by the knocks and bashes of a regular club regata as well as transport. That said, I have heard that there are many home builders which have succesfully used balsa/glass cloth construction. I remember seeing a webpage dedicated to balsa/grp construction but looking for it now I can't locate it.

Steve Landeau · Post by **Steve Landeau** » 21 Jan 2004, 02:43

From my experience in flying and building aerobatic r/c aircraft, I found using hairspray on the balsa once before final sanding, then again after final sanding was a very effective way to seal the surface of the wood before appying epoxy.

CARDOSO · Post by **CARDOSO** » 21 Jan 2004, 13:52

Hi all

We use with sucess "samba" wood. Is strong at knocks, very good to built, and easy to work.
It didn't absorb to much glue (Araldit or similar) and you can use epoxy resin. Results very good.

At final you can paint or varnish. Loocks very nice (and strong)

Regards
J. Cardoso
POR67

Roy Thompson · Post by **Roy Thompson** » 22 Jan 2004, 13:33

I don't know if 'Samba' is the name of this wood all over the world, but we have it here in Spain also. Yes, although it's tougher than balsa it's almost as easy to work. Maybe not as clasically beautiful as cedar but easier to find, often cheaper than balsa and comes in many sizes (up to 2.4m long and sections ranging from 3x8mm to 30x50mm). The Portuguese boats I have seen built with this material are spectacular! It certainly doesn't need any fibreglass reinforcement at all, with a couple of coats of epoxy (or paint or varnish - whatever you like) outside it's as tough as anything.