steam bending sapeli for optimist

[cirrus]

Hello, I am building an optimist and I want to steam bend some sapeli für the gunwhale
stringer. I want to make it from of three pieces of 15 mm x 35 mm x 2400 mm.
The radius is not so small, and I can bend it in the desired form without steaming.
However, even after 2 hours steaming and one night clamping to my mould, the board
snaps back and the curve has gone.

I have read the exotic woods do not bend well. Is that true for sapeli?
Or Do I have to steam for a longer time?

My second question is, can I glue the three pieces together on my mould an will they stay in the form
without steaming? The stringer is twisted a little bit.

Thank you

Cirrus

[Buddy]

Ah, the universal Opti. I instruct kids on these and I have seen a great many woodies, talked to the Dads who built them. Everything from practically "crates" to museum piece "furniture". Built similar El Toro's myself. I never came across any parts that needed steam bending- rubrails, chine stringers, keel strip. The radius is so great with no concentrated curves, glue holds them easily. The parts are so small in section they won't distort the curve of the plywood panels. Remember, the Optis were originally designed by Clark Mills to be something the dads in Clearwater Florida could build themselves for their kids instead of Soapbox Derby racers because there were no hills. I am still embarrassed to see what the adults have done ( to the kids as a whole) to be "competitive" - there are got-to have= to- win $4500 boats out there. This for a that boat was designed to be simple for first time/ only time builders at home.

[Lulworth]

I just finished one opti (or nearly so) and have three more opti's to go and, trust me, you don't want to steam bend anything. I've already completed three pairs of laminated inwales for the remaining three optis (four pairs in total) so I have lots of opti inwale/gunnel experience. In the end I used a mix of red and white cedar (mostly red; in two of the sets, I laminated using four 12 mm layers and, in the other two, I used five layers of thinner wood. Both had minimal spring back but I'm storing them on a frame to be sure.

You need to be careful with the tolerances on these "simple" boats in order to measure-in by the class. If you don't care to race then this boat is dead easy to build. You are probably more skilled than I (most are!) but I have found it very tough to meet the +/- 2 or 5 mm tolerances (measured in 50 different places). You need a form to bend the inwales on, use the measurements given in the plan view sheet.

Also, I think (could be wrong) that sappel is fairly heavy (dense) compared to mahogany and is definitely so compared to red cedar. If you're thinking of racing, don't use a heavy wood for the gunnel.

oops, I see you are using a form. Three layers is one fewer than I would go for - there wil but it's also likely that the pre-bending by steaming will reduce the spring back. If it doesn't, and the glued laminated 45 mm thick inwale springs back a bit, it will be easy to force it back into position using the center frame, mast thwart bulkhead and transoms (fore and aft). Measure again and again to be sure those beam measurements are right before gluing.

Good Luck,

David

[ 01-12-2005, 02:24 PM: Message edited by: Lulworth ]