Steaming and laminating

Keith 66

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Usually much quicker to steam bent the timbers provided you can get them into place OK under the beamshelf and bilge stringers.

Iroko steams quite well too – Dagless used Iroko steam bent timbers in many of their Fleur de Lys class motor yachts. Worth trying.

Cheers -- George

Are you sure it was Iroko? post war rock elm was becoming scarce & an alternative steaming timber called Danta became popular until it too became scarce. I used some in the 80's (left over old stock) It steamed ok & looked like reddish iroko with heavily interlocked grain.
Another good timber for steaming is Locust or False Acacia, it is highly durable & a surprising amount of trees are about though it rarely comes available.
 

AntarcticPilot

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Another good timber for steaming is Locust or False Acacia, it is highly durable & a surprising amount of trees are about though it rarely comes available.
It's actually quite a common garden tree in larger gardens, being reasonably decorative. There was one at my previous home, which had an enormous garden.
 

debenriver

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It's actually quite a common garden tree in larger gardens, being reasonably decorative. There was one at my previous home, which had an enormous garden.
We have two of them in our yard here in Rockland, Maine (Black Locust/False Acacia) – they are about 80' tall. Millions of small white flowers in early Summer, which get seriously stuck to cars in the driveway when they fall. Its a very dense (SG at 12% MC = 0.77), hard, strong, durable timber often used in boatbuilding for frames and structural members, sometimes decking. It does indeed steam very well. Turns well too, very attractive grain. Varnishes nicely. Growth rings are incredibly close.

Actually it's quite surprising how many timber species do steam well.

Cheers -- George
 

ianc1200

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Re steaming/bending iroko, we were using iroko left over from the last major rebuild of this boat in 2002/03, found it split/cracked very easily. But the recent iroko I've bought seems a lot more able to bend.
 

burgundyben

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There's some teak, its reclaimed off the deck of a ship, the tree must have been cut down 100 years ago, if I milled it into 6mm by 40mm and steamed it, do we think I could edge set it to a swept deck?

Or is wood that old never likely to steam well?
 

debenriver

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Oddly enough I never remember having to steam teak decking for swept deck planks – they always just went round without a problem. After all it's usually a fairly gentle curve. Thinner planks (for epoxy bonding) are a little more troublesome, but again, we never had to steam any.

Ships' teak decking used to be generally 2½" x 5" (63 x 125) – is that what you have, approximately. If so you need to cut it for vertical grain, so sometimes you have to cut and cut again – cut to the desired plank width and then cut the thickness. Sometimes you can simply slice them off at the thickness (so you'd end up with 63 x 6mm). But you do need to get vertical grain as best you can. Then I think it will pull round without steaming.

Cheers -- George
 

burgundyben

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Oddly enough I never remember having to steam teak decking for swept deck planks – they always just went round without a problem. After all it's usually a fairly gentle curve. Thinner planks (for epoxy bonding) are a little more troublesome, but again, we never had to steam any.

Ships' teak decking used to be generally 2½" x 5" (63 x 125) – is that what you have, approximately. If so you need to cut it for vertical grain, so sometimes you have to cut and cut again – cut to the desired plank width and then cut the thickness. Sometimes you can simply slice them off at the thickness (so you'd end up with 63 x 6mm). But you do need to get vertical grain as best you can. Then I think it will pull round without steaming.

Cheers -- George

Thank you, it hadnt crossed my mind that I might need to saw the decking vertically.

The deck I might need to lay is quite a tight curve up in the bow, much tighter than a swept deck on a sailing boat.
 

debenriver

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Right, I appreciate that on a motor yacht the bend forward does get quite tight, but even so I'd try dry first. The problem with steaming thin boards is that as you edge bend them, they tend to buckle up. But I guess the only way to find out is to try if they won't go dry. The old ships' decking is very unlikely to have been kiln dried, so it should steam bend ok.

And, yes, for the deck to wear well and lay nicely, you need to cut the planks to get as best you can vertical grain like this (idealized) image:
grain.jpg
Otherwise, in use the deck won't wear well and the grain will also tend to shell out. You're unlikely to get it all as perfect as this of course! Vertical grain boards should also edge bend better too.

Cheers -- George
 

burgundyben

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Right, I appreciate that on a motor yacht the bend forward does get quite tight, but even so I'd try dry first. The problem with steaming thin boards is that as you edge bend them, they tend to buckle up. But I guess the only way to find out is to try if they won't go dry. The old ships' decking is very unlikely to have been kiln dried, so it should steam bend ok.

And, yes, for the deck to wear well and lay nicely, you need to cut the planks to get as best you can vertical grain like this (idealized) image:
View attachment 172233
Otherwise, in use the deck won't wear well and the grain will also tend to shell out. You're unlikely to get it all as perfect as this of course! Vertical grain boards should also edge bend better too.

Cheers -- George

I would call that 'quarter sawn', such boards being easier to edge set news to me and helpful.

Thank you.
 

Hacker

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It’s because the “upright” grain acts a bit like a stack of laminates and allows the sections to “slide” on each other. They don’t actually slide but they allow the fibres to bend with no obstruction. We did a new deck on a 1910 Truro oyster dredger a couple of years ago, but we straight laid it.
 

debenriver

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Well yes it is like quarter sawn. If what you you can obtain is ships' decking (as I mentioned, often 2½" x 5") then it will likely itself have been quarter sawn originally. Hence the need to cut and re-cut to get vertical grain in your 6mm thick boards. If you just slice them off the edge of the old decking you won't get vertical grain in your boards.

We always bought ships' teak decking for teak decks (both solid thick teak decks and thinner epoxy bonded teak decks) and I would say that at least 70% would have to be cut and cut again to get the best grain for the job. Covering boards, margins, king planks etc. would be cut from ordinary plain sawn teak boards (preferably cut close to the heart), but these are generally cut to shape where necessary, not sprung. But teak of this sort is really not available nowadays anyway,

Cheers -- George
 

ianc1200

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As an update, having inserted two doubled gunnel to gunnel iroko laminated replacements plus some shorter one's as well for the heads area, after Christmas we moved into the fore-cabin, certain it would be easier further aft in the boat we went. It proved not to be so. The first pair aft of the heads/fore-cabin bulkhead buckled upwards at their rear edge at the sharp turn of the bilge. After a few days agonising, I had them removed, copper nails, roves and all. We then experimented and found the solution was steamed iroko laminations, but because wet from steaming had to changed to polyurethane glue. This seems to have worked remarkably well, such that we are considering continuing on like this rather than dry laminations with epoxy + gap bonding filler.
 
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