Coaming

[ecgossett]

I've been having trouble getting my wood not to crack on installing corners for the coaming. The best luck I've had on not cracking is wrapping 20inch piece of coaming in towel, pouring hotwater over and sticking in microwave for 6, 2 minute intervals with 2 minutes in between.

Any suggestions to improve this?

How are the coaming sections commonly attached? Scarfing, butting joining?, If it's scrafing it seems painfull to prescarf everything because if anything winds up being off somewhere a gap will happen.

- Edward

[Ray Frechette Jr]

Soak your wood overnight in cold water before wrapping in towel and pouring hot water.

Are you trying this with 6 mm ply or solid wood?

If ply is it Merranti or Okoume?

How tight a radius are you trying to bend to?

[ecgossett]

Soak your wood overnight in cold water before wrapping in towel and pouring hot water.

Are you trying this with 6 mm ply or solid wood?

If ply is it Merranti or Okoume?

How tight a radius are you trying to bend to?

Okoume, and 18 & 13" radius per the plans. Butt joined or scarfed?

[Peter HK]

If you are not concerned with grain orientation, eg if you are going to paint, then orienting the ply so that the 3 of 5 veneers have the grain vertical and only 2 veneers have a horizontal grain means that it bends much more easily. I didn't need heat or soaking at all.

I used simple butt joins but added a second strip of ply on the outside of the coaming above deck level to give it a more durable and comfortable half inch edge and staggered the butt joins.

Cheers

Peter HK

[Ray Frechette Jr]

OK, I routinely bend down the 6 mm okoume to stock radiuses with grain running along length without problem.

As mentioned I soak blanks in a 40 gallon trash bucket overnight before heating in a bath towel with boiling water.

The front curves are gentler curve and I simply pull out of towel and instantly bend to a right angle in the air as I walk into boat to clamp in place. IE: pre bend it once out of towel and then ease into place on boat.

For the tighter rear radius's I have a bending jig I built out of laminated 2x6's. I bend to that tighter radius over the curve to support the piece as it is bending and support the fibers in compression and clamp in place overnight as it dries.

I bend all four corners oversize. IE they are trimmed down to length after cooled and fitted to the boat and are but joined on the boat.

I also have the blanks about 4-5 inches wider then finished pieces. IE; I cut down the width after cooled. This may prevent splitting and breaking as well instead of using templates of card stock to get exact width prior to bending.