Author Topic: ELB Trilam question  (Read 8302 times)

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Offline adb

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Re: ELB Trilam question
« Reply #15 on: November 09, 2013, 01:10:40 pm »
If those were my choices, I'd use: hard maple (forget the soft stuff for anything), ash, hickory, and white oak for backings. Jatoba, purpleheart, and greenheart make great cores. Of you list, I'd only use ipe as belly wood. If you can get osage, use that too. You can interchange ipe/osage on the core/belly as well. Of course, with lumber, it's all about the grain. If you want a good source of great osage lumber, all quarter sawn, send me a PM.
« Last Edit: November 09, 2013, 01:14:02 pm by adb »

Offline adb

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Re: ELB Trilam question
« Reply #16 on: November 09, 2013, 01:16:00 pm »
Maybe maple is good. But ash is good in tension too. I use hickory and ash. Maybe American maple is better than european. Hickory was the choice number one in victorian longbows  from the 18 th century. :-)

Maybe maple is good? No. Maple is good.

Offline Bowman

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Re: ELB Trilam question
« Reply #17 on: November 09, 2013, 03:05:12 pm »
Maybe maple is good. But ash is good in tension too. I use hickory and ash. Maybe American maple is better than european. Hickory was the choice number one in victorian longbows  from the 18 th century. :-)

Maybe maple is good? No. Maple is good.
Yes sure. Canadian maple. But in Norway I prefer Ash, and sometimes I get perfect hickory, imported from america. :-) Bamboo is a good choice too.
"for veik var kongens bue......."

akswift

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Re: ELB Trilam question
« Reply #18 on: November 09, 2013, 04:21:18 pm »
I have always read that Maple is a good choice for cores , and certainly there have been excellent maple-backed bows constructed, but what is the advantage of using heavy woods like ipe for cores?
Ipe seems to have qualities better suited for the belly, and something lighter with good glue-ability would be desired for cores. Comparing two identical designs with the same back and belly, wouldn't a bow with a lighter core have better cast ?

Offline adb

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Re: ELB Trilam question
« Reply #19 on: November 09, 2013, 07:51:06 pm »
The core is under compressive forces, like the belly. Therefore, use compression strong wood. Any wood will not work for the core. Do a search on this forum for (I think) padauk as a core... I believe toomanyknots started it... core wood will chrysal if it's the wrong wood.

Maple is a good (and usuaully first) choice for cores in a FG laminated bow, and is used widely in that application. Nothing even remotely similar to an all wood tri-lam bow.

akswift

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Re: ELB Trilam question
« Reply #20 on: November 10, 2013, 01:21:07 am »
No doubt that core wood will chrysal if it is the wrong wood, but it seems that it would take a lot of maple to put the core in compression if the belly was ipe or osage. I read the older threads, and am more confused than ever. Do you make your three lams all about the same thickness, I was looking to build a laminated bow soon, and am curious what thickness proportions most find give good results.
Thanks

Offline adb

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Re: ELB Trilam question
« Reply #21 on: November 10, 2013, 10:38:44 am »
I usually make my backings 1/4". Maybe sneak it up to 3/8" on a heavy warbow. My cores will be the same, or slightly thinner... maybe 3/16". I like to have about 3/4" of belly wood to work with.

Included a pic of a tri-lam with those proportions:
« Last Edit: November 10, 2013, 10:45:20 am by adb »

Offline Bowman

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Re: ELB Trilam question
« Reply #22 on: November 10, 2013, 12:41:35 pm »
Beautiful bow and nice combination. What is the name of the maple you are talking about? I'm curious, because the maple home in Norway are useless as backing in a bow.  :)
"for veik var kongens bue......."

Offline adb

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Re: ELB Trilam question
« Reply #23 on: November 10, 2013, 12:47:58 pm »
Acer saccharum

akswift

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Re: ELB Trilam question
« Reply #24 on: November 10, 2013, 01:15:49 pm »
Thanks for posting the close-up of your bow. Your craftsmanship shines and the contrast of color gives a striking appearance.
 One of my criteria for selecting materiel for my next bow is to test out the performance of local woods, and birch is readily available, and similar to maple, but not generally considered a good wood for compression.


Quote
Nothing even remotely similar to an all wood tri-lam bow.

what dissimilarities have you found building wood trilams? The wood I want to use on the belly is not easy to obtain in thicker sections, and I was hoping to get by with a thinner belly lam and a thicker core, but now I wonder if there is more to be considered in design than the "physics" of bending

Offline adb

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Re: ELB Trilam question
« Reply #25 on: November 10, 2013, 02:08:38 pm »
In making FG bows, the 'core' is simply a platform to hold the FG. It does nothing else. I believe maple is widely used because it's easy to work, the dust is non-toxic, it's light weight and a neutral color.

Birch is extremely marginal bow wood. Much like poplar. It has to be very wide and flat to make a decently functioning bow. Not a candidate as a backing, either. NOTHING like maple. It will make a bow, but not one I'm interested in. There's lots of birch where I live, but I don't even bother with it. Birch is great firewood!

We've already discussed the pros and cons of thicker cores and thinner bellies... you just need to make a decision now.

If you have thin slats of say osage or ipe, and can't easily get it thick enough... glue 2 pieces together to make your desired thickness.
« Last Edit: November 10, 2013, 02:13:18 pm by adb »

Offline toomanyknots

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Re: ELB Trilam question
« Reply #26 on: November 10, 2013, 02:52:58 pm »
I usually make my backings 1/4". Maybe sneak it up to 3/8" on a heavy warbow. My cores will be the same, or slightly thinner... maybe 3/16". I like to have about 3/4" of belly wood to work with.

Included a pic of a tri-lam with those proportions:

I wish I could make backings as thick as 3/8". Finding backing quality wood is such a pain for me, I am prone to use just as much as I need, usually about an 1/8" or so. Can I send you a PM about that osage?, lol.
"The way of heaven is like the bending of a bow-
 the upper part is pressed down,
 the lower part is raised up,
 the part that has too much is reduced,
 the part that has too little is increased."

- Tao Te Ching, 77, A new translation by Victor H. Mair

Offline adb

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Re: ELB Trilam question
« Reply #27 on: November 10, 2013, 02:54:14 pm »
I usually make my backings 1/4". Maybe sneak it up to 3/8" on a heavy warbow. My cores will be the same, or slightly thinner... maybe 3/16". I like to have about 3/4" of belly wood to work with.

Included a pic of a tri-lam with those proportions:

I wish I could make backings as thick as 3/8". Finding backing quality wood is such a pain for me, I am prone to use just as much as I need, usually about an 1/8" or so. Can I send you a PM about that osage?, lol.

Yes.

akswift

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Re: ELB Trilam question
« Reply #28 on: November 10, 2013, 09:48:15 pm »
Thanks for your most recent reply, adb. It was just what I needed to make a decision.

Offline kevinsmith5

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Re: ELB Trilam question
« Reply #29 on: November 10, 2013, 09:55:08 pm »
If anyone is in or near eastern NC and looking for decent wood for bows (other than Osage) PM me and I'll tell you where I get all mine.

PS- having never tried to make a bow of birch I'll take ADB's word for it, but dear lord don't burn it. I've made some beautiful furniture out if it.