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Re: Steam bending vs glue-laminated

Posted by Sandy 
Re: Steam bending vs glue-laminated
September 05, 2019 12:34PM
........I split this off the Don Hill thread.

I steam bent a set of ash or maybe it was white oak gunwales 35 years ago and never again. I bought two pressure cookers at the second hand store and fed the steam into 4" inch galvanized conduit, with custom made caps built with brazing rod and plumber's compression fittings. It worked. It was a pain in the butt. I never did it again.

After the hot gunwale blanks come out of the steamer they're like a big spaghetti noodle. You can really bend it. But that flexibility only lasts for about 60 seconds. Five minutes later it's almost all gone. You need four sets of hands and I don't have that many. I've heard stories about boiling the wood in vats of water mixed with Downy Fabric Softener. I never tried it.

I used 3/4" inch fir for many years, which you can carefully bend, starting at the middle and working out left and right to the ends, like torquing head bolts on a V8 engine. I watched my local lumber yard and picked off all the 18' and 20' foot clear vertical grain fir boards that dribbled in. I still have one such board in my shop. I may never cut it. They're almost extinct now and I like just looking at the one 20' foot board I've got left.

Last few boats I've made laminated gunwales with ash where I rip the gunwale stock into 1/4" inch strips and glue it in place, on the side of the boat, with Visqueen backing and a half a zillion C-clamps. And Tightbond III glue. Four layers thick with staggered butt joint ends makes a 1" inch gunwale, which is enough. You don't need two gunwales. Just one. A full 1" inch thick, placed inside or outside. That part is up to you.

Ash glue-lams are the best gunwales there are. There is no compromise involved. Ash glue lams are the best you can make.
Re: Don Hill
September 05, 2019 12:54PM
One more note on ash glue-lams. I used to make gunwales with 3/4" inch fir 1-3/4" tall. The few times I tried to make 2" inch tall gunwales it became too hard to bend.

With ash gluelams, made from 1/4" inch thick strips, you can make the gunwales a full 2 or even 2-1/2" inches tall, which greatly increases stiffness.

You can also stagger the vertical height of the gunwales as you gradually build up the gunwale, using a 2x4 across the boat, so the top of each lamination strip is flush to the bottom of your cross-gunwale 2x4 guage. That way the top of the gunwale ends up parallel to the shop floor, with a slightly notched top edge, which you can knock down to smooth with a power plane or a right angle grinder. Or both.

Now, with a curving but flat-topped gunwale edge that parallels the water you can build the deck (of a decked white water boat) so it spans the top of the boat, rather than placing it six inches down from the gunwale, as most Briggs builders do.

A decked boat that has the deck 6" down from the gunwale creates a 200 gallon bucket that fills with water each time you crash a big wave, that takes up to ten seconds to drain out, which makes the boat temporarily unmanageable. The Dayak has a deck flush with the top of the side panels. It drains instantly. Actually drains is misleading. It never fills in the first place. Laminated gunwales are the way to go.

And for decked boats so are decks flush with the top edge of the side panel, so the top of the boat isn't a custom made 200 gallon water receptacle.
Re: Steam bending vs glue-laminated
September 06, 2019 12:32PM
On the recent Buffalo I used Western Red Cedar for the gunnels and it is beautiful. It is also very soft and already dented in many areas. I love to work with it but never again for gunnels. I used the 1/2 x 2" pieces inside and outside but forgot to level them across the span. They look nice though.
The idea of using ash as 1/4" laminates never occurred to me. I'm surrounded buy Ash lumber and it would have been nice to use. I never thought about the use of staggered butt joints on the laminates. Good tricks for those of us with lots of ash. Thanks for sharing that.

By the way. I live in PA. My favorite wood to look at and to work with is quarter sawn Fir. Air dried fir is, so far as I've found, not available on the east coast. If I could find it locally and reasonably priced I'd use it allot more. Currently, if I want quarter sawn fir, I cull through the stacks of 2x12 at box stores in NJ and select the best of the grain I can find then I cut it out as needed on the table saw. I live right on the border of PA and NJ. In PA they call It Hem/fir. It may be fir, it may be hemlock whereas in NJ it must be Douglas fir to meet the building codes. As with most kiln dried softwood varieties it can be brittle if holes aren't predrilled and has limited bending capability..
Re: Steam bending vs glue-laminated
September 06, 2019 01:15PM
long clear vertical grain douglas fir is almost extinct in the Pacific Northwest, where it comes from.

I did tear down an old two story garage once, just to get the 18' 2x8 fir rafters the roof was framed with. Same deal at an old mine building in Trinidad Colorado a zillion years ago.
Re: Steam bending vs glue-laminated
September 06, 2019 01:47PM
Sad how we ripped through that species. I was an arborist for my younger life and for a year I did my dream of working in the redwoods around Eureka. Ironically the tallest tree I climbed was a dead Doug Fir in some grove south of Fortuna. In those days the bark of Doug fir was cubed for sale to be used as firewood. Doug fir is a magnificent species.
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