Thread: Steam bending ribs for kayak

G'day sumedho,
What size stock are you trying to bend??
I've successfully used pine for a bent hoop project, but I cut the pine into 3mm strips, which I bent, then laminated with Titebond Epoxy.

The standard width for ribs is 6mm and for the coaming 3mm laminated. When I went to the timber yard they looked at me like I was an alien when I asked them about steam bending woods. Thats why I asked here.

Some people have suggested using sheoak and also spotted gum. I'm lucky cause I live on a farm and have access to branches that have fallen off these trees. So I'm gonna give those two a go I think. Anyone had success bending sheoak or spotted gum?

Howdy - I replied to this a few days ago but I think I forgot to post it properly.

This is not my area of expertise - but my understanding is that to steam bend hardwood it it should be green timber - not dried much at all.

Also it depends how you are trying to steam it. Generally a pipe or box with a continuous supply of fresh hot steam going in the bottom and a rag in the top.

If having problems of this type you could always laminate the ribs out of smaller pieces of timber. What you are using is pretty small already - but if you laminated out of three layers of 3 or 4mm softwood it would probably bend easily without any steaming. 12mm of softwood probably would be around the same weight as the 6mm of hardwood you are going to use and will be much stiffer because of the thicker ribs.

But you should have a look at whether thicker ribs would interfere too much with anything that happens internally.

A picture of the jig is below - using the screws like this leaves indents from the threads in the timber - a bunch of right angled shelf brackets screwed along the lofted line would work more nicely. You can do Port and starboard pairs on the same jig at the same time.

Best wishes
MIK

Spotted gum steam bends well. I don't know about using branch timber, I'd use normal sawn heart timber.

Cheers,

To bend the timber you need to get it up over 200 Deg. 220 deg ideally.

I have attached some pics of my steam box setup. I am currently repairing an 18ft launch and replacing a lot of the broken ribs.

The new ribs are unseasoned spotted gum.

They require about an hour in the steam box to bend well.

Craig

I switched from kayak building to guitar building a few years back (guitars are easier to carry). I can tell you that the instrument makers have bending wood down to a fine art.

If I were to go back to kayak building I'd chuck out the steam box and use a bending iron to bend thin stock and laminate them.

Why do want to make the ribs out of hardwood? That'd make the boat pretty heavy, douglas fir (oregon) and cedar bend well as thin lamintations and don't weigh much.