carpentry

[Micky]

Woodwork is not one of my best DIY trades.
I need to replace some wood trim to my wheelhouse that has a bend, banana shape, and a twist. This fits across the cabin roof along the bottom of the screen, so has a two way bend.

Question is how do boat builders bend the wood to fit without it snapping and fit snuggly up against the contour of the area it is to be fitted.

 

[Evadne]

Most wood can be steamed, which makes it easier to bend (but not teak).
Or you can laminate it by gluing on several very thin strips of wood.
Or if its less than an inch think just take it carefully and you might manage it without splintering.

To get a snug fit either clamp it (not always possible), using G-clamps with bits of wood under the jaws, or screw and glue. This is the method I would use, if the job is as I imagine it from your description.
If you drill a larger diameter hole (counter bore) so that the heads of the screws are below the surface you can glue in wooden plugs which can be then planed off. For extra invisibility, buy a plug bit for your drill and make the plugs from the same material as you are fitting, rather than buying them off the shelf from the swindlery.

 

[Norman_E]

Dave gave good advice.
Most wood can be steamed, but it is not just a question of holding it over the kettle spout. What you really need to do to make an amateur steamer is get a length of pipe big enough to take the piece of wood. Put the wood in with a couple of wedges to keep it in the middle of the pipe. Prop the pipe up at an angle (suggest about 30 degrees from horizontal) Set up an old fashioned kettle to put steam in at the lower end. Put a piece of rag loosely in the top to stop the steam getting out too fast, and keep the kettle boiling as long as possible. I think a half inch thick piece of wood really needs half an hour.
Make sure your wood is straight grained and knot free, otherwise it is difficult to get even bends. The final point is that you must steam the wood close to where you want to use it, as it rapidly loses flexibility as it cools. Therefore get it out of the steamer (using thick gloves) and get it into place and clamped down as fast as possible. If there is a boat builder where you keep your boat, they probably have a steamer, in which case it is probably best to get them to do it for you.

 

[cliff]

[ QUOTE ]
Question is how do boat builders bend the wood to fit without it snapping and fit snuggly up against the contour of the area it is to be fitted.

[/ QUOTE ]Tricks of the trade!

Joking aside, the easiest way is to make a cardboard template first, craft card or similiar is good, or even use hardboard which will bend easily. The curve across the deck is not bent but rather the timber is cut like a banana then the bend around the "window" is only in one axis. It is difficult to bend timber thicker then ¾"~1" so if oyu have a ¾" thick by 3" wide piece it will bend reasonably easily in the ¾" direction but not in the 3" direction hence cutting a profile out of the 3" width if a compound bend is needed and hence the cardboard or hard board template.
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“I’m as confused as a baby at a topless bar. “

 

[VicS]

Just an aside really but I learnt from somewhere recently that it is elevated temperature rather than steam as such that is required for bending wood.

Apparently the lignins in the wood soften a tad below 100C so the steam is a convenient way of getting to that sort of temperature. It does mean that you have to have a sufficiently powerful steam generator to get the whole of the length to be bent up to 100 and to steam for long enough to get the wood heated right through. Also, of course, you must do the bending before the wood cools too much.

Take great care, boiling water and steam can inflict nasty burns. It would be a good idea to have a supply of cold water handy to cool any burns if you are not near a tap.

 

[Micky]

Cheers for the tips gent's.
I think i will go for the cutting idea for the curve over the cabin, then i might be able to ease it into the area needed up against the screen.