How to make a teak caprail curved in two planes

[Keith-i]

Any thoughts on what this might be. It's marketed as teak but from what I understand genuine teak is not available. It's the only offcut I have left so sorry for the limited picture.

 

[Hacker]

Basically a joiners rod is a full size drawing of the part to be produced giving details of any joints. Very similar to setting out the lines of a boat on a lofting board. What it means is that you can draw the transom and then fit the wood to the drawing knowing it will then fit. In this case you could just the drawing to set out any blocks to wither use to fit a steamed piece of wood or to laminate the piece.

 

[coopec]

@coopec, technically it's a Hardwood, but there aren't many softer less durable hardwoods (poplar's in there with a shout).
Lots of external Joinery is made with meranti but I think it's only a cost thing. So that the manufacturer can claim that its made of hardwood. It seems as though 9 out of 10 bits of external Joinery that I have to repair /replace because of rot are meranti. I'm not trying to bash what you've done but if you can find something else to use externally then I think you'll find it lasts longer.

I've even thought of using marine ply as it would make the job so much easier. With a coating of Sikkens Cetol you'd hardly notice it wasn't solid timber.

 

[Hacker]

@coopec there is no way on earth that you will be able to bend ply of any decent size, especially in 2 planes. In one plane you could kerf the back at narrow intervals to obtain a curve but even then you run the risk of splitting out the front face.

 

[coopec]

@coopec there is no way on earth that you will be able to bend ply of any decent size, especially in 2 planes. In one plane you could kerf the back at narrow intervals to obtain a curve but even then you run the risk of splitting out the front face.

I can bend 5mm ply quite easily. Then I would laminate a second layer to give an overall thickness of 10mm.

As far as the vertical curve is concerned I wouldn't try to bend it! I'd cut it in an appropriate curve to conform with the curve of the toe rail.(How am I going?)

 

[Hacker]

Ok so far! Personally I wouldn’t use ply for that, but that would work although possibly a bit wasteful of ply depending on how wide the curve is.

 

[Kilo]

@coopec there are a couple of things worth considering. If I've understood your plan with the ply you'll create the curve in the horizontal plane (around the back of the transom) before cutting the piece to give the curve over the transom? In that case I think you'll end up with the ply(s) open on the top face & still needing capping. In which case you're going to have to put a piece of solid on top.
If you're happy laminating the ply maybe just do it with thin solid instead. It is more involved as you have to be able to plane up or source thin stock but at the end of the process of laminating for the biggest radius and then cutting for the other you've a solid lump that can be sanded & shaped.
Writing all that & giving the process more consideration only goes to reinforce the fact that they did it right the first time and it should be steamed.

 

[coopec]

Ok so far! Personally I wouldn’t use ply for that, but that would work although possibly a bit wasteful of ply depending on how wide the curve is.

The curve is probably 4/5 inches vertical and I'd say about 12 inches horizontally. I'm quite happy to use half a sheet of ply because in the scheme of things it is not too expensive.

I thought a lot about it, I don't want to steam timbers and I don't want to take forever to fit it. If you come up with any ideas let me know. ?

 

[coopec]

@coopec t
If you're happy laminating the ply maybe just do it with thin solid instead. It is more involved as you have to be able to plane up or source thin stock but at the end of the process of laminating for the biggest radius and then cutting for the other you've a solid lump that can be sanded & shaped.
Writing all that & giving the process more consideration only goes to reinforce the fact that they did it right the first time and it should be steamed.

This is a boat I am building. I'm not sure how the yacht architect thought it should be done but I wish I had built a much flatter transom like they did on this steel Mauritius 43. (That would be relatively easy to cap the transom)

 

[Hacker]

As Kilo says one of the issues with laminating the ply is that you are likely to end up with open grain in a number of places. Although you could seal with epoxy it is likely to suck up water at some stage. If you really don’t want to steam then the second best would be to laminate solid timber to one curve and then cut out the secondary curve. Having done both methods the steaming one is far easier.

 

[coopec]

As Kilo says one of the issues with laminating the ply is that you are likely to end up with open grain in a number of places. Although you could seal with epoxy it is likely to suck up water at some stage. If you really don’t want to steam then the second best would be to laminate solid timber to one curve and then cut out the secondary curve. Having done both methods the steaming one is far easier.

Tell that to people sailing marine ply yachts! But I would follow recommendations to avoid "open grain".

If I wanted to bend solid timber it would need to be 6in(?) wide and (say) ¼in. thick and that would be very difficult to bend. I doubt I could buy timber in those dimensions anyway.

 

[Kilo]

I'm sorry that neither of us are giving you the answer your looking for. The main thing is that you make choices with plenty of info & that you know why you've settled on one option or another.
Looks like a lovely boat, have fun.

 

[Hacker]

I echo @Kilo comment, it is your boat (and a lovely one at that). Having just restored a ply Flash boat I understand the issues of bending ply and how it can suck if water if there is any breach of the sealing. We regularly bend planks upto 1” thick when carvel planking. It also surprises me how much edge set you can get on quite a thick plank. Love to see pictures when she is finished.

 

[coopec]

I echo @Kilo comment, it is your boat (and a lovely one at that). Having just restored a ply Flash boat I understand the issues of bending ply and how it can suck if water if there is any breach of the sealing. We regularly bend planks upto 1” thick when carvel planking. It also surprises me how much edge set you can get on quite a thick plank. Love to see pictures when she is finished.

I build in fiberglass! (You blokes are completely out of my league) ?
(Sparkman and Stephens are my favorite yacht architects)

 

[HissyFit]

Old thread on the Classics forum suggests soaking the wood first.

Steam Bending Teak

 

[Hacker]

Soaking first does help, ideally in salt water. We recently finished a new Cornish Pilot gig and all the ribs were steamed in after a good first soak. One of the builders at Gweek submerges them into the creek, they come out very brown!