Primitive Archer
Main Discussion Area => Bows => Topic started by: kevinsmith5 on November 06, 2013, 08:05:34 pm
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I'm thinking of doing a white oak, hard maple, Ipe trilam. Maple core, white oak back, Ipe belly, 76", continuous taper from 1-1/4" x 8" handle to 1/2" tips and total length 78" (ntn @76"). My questions are if it was you how thick would you go on the Ipe and ae if you wanted 75-90 lbs? I usually use white oak as a 1/8" backing.
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1 1/4" is too wide I think for an ipe bow of this weight. You wanna go 1 1/8" wide at the handle, for glue up dimensions, and then you might wanna take that down a bit too during tiller, etc.
- 1/8" thick backing
- 1/4" maple core, tapering to somewhere in between 3/32" and an 1/8" or so at the ends.
- 1/2" to 9/16" ipe belly.
This is based on my notes from making similar bows at 75" or so nock to nock. A full inch thickness with these dimensions can easily give you 120# @ 32", so I think 7/8" to 15/16" should be more than enough meat for you. I think it is important to taper your core with softer cores such as maple as well, only because you can get set in the tips if you don't. Although I am pretty bad at remembering to taper them myself, ;D.
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Yep 1 1/4 is too wide. Ok for glue-up but the finished bow definately won't need to be wider than 1 inch at the handle.
I personally would go for a 1/4 backing and an 1/8th core...then no need to taper it ;) but that's really just personal preference...although i'm not 100% on it but I think thicker backings work well with ipe and other very dense woods.
Toomany's advice is spot on.
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I'd go 1 1/8" wide at the handle, 1" total depth thickness. Continuous taper from a 4" handle to 1/2" tips and continuous belly taper from 1" thick at grip to 1/2" at tips. I'd also make the backing 1/4" and the core 1/8". The core should be compression wood so maple isn't your best choice, but it should be OK. Make your tiller just a sniff elliptical, and it'll be a sweet shooter.
Here's my interpretation of good tiller for a long tri-lam ELB...
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Is that core ipe?
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Yes. Maple back, ipe core, osage belly.
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Nice looking bow, great tiller.
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My experience is that hickory is a better choice in the back. I use white oak in the belly, but Ipe in the belly is perfect. Maple is a good choice in the core. Good luck. :-)
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Hickory is a good choice on the back. So is maple. I've made maple backed yew warbows up to 120#, so maple is plenty good in tension.
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Hickory is a good choice on the back. So is maple. I've made maple backed yew warbows up to 120#, so maple is plenty good in tension.
I like maple a lot too because it is lighter than hickory. If I wanna really light weight quick shooting bow, I find maple for the backing works great.
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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. :-)
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I haven't had a great deal of luck with rock maple for backing. Out of 4 attempts 2 were good. Those two I meticulously followed the grain, they were done by hand, not from a saw or planer, like I would use for hickory. The one's I tried like hickory sawn slats both blew on me at full draw, despite being exercised to full draw many times.They had very straight grain too.
It could've just been a bad board for the ones that blew, because the hand worked ones that followed the grain came from a different board.
The really good thing about rock maple was it gave significantly less stringfollow than hickory.
Maple obviously works as a backing. (Top job adb)I just think the grain has to be dead straight, or maybe even taken down to a growth ring when you get to really narrow bows like you do when you use ipe.
Haven't used Oak as a backing yet, but said to be on par with hickory if you use US white oak and its straight grained.
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You might of just got a bad piece. I think it happens sometimes. I bought a bunch of hickory once, perfectly straight grained. And it would not make a bow for nothing. Every little piece broke. It is now barbeque wood.
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I've had great luck with maple as backing and self flatbows. ELBs, laminated flatbows, and laminated warbows... very few failures. Maple is actually one of my favourite woods. Canadian maple, mind you! Hard sugar maple.
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For reference here is the list of woods I have or have access to for sure through my local wood lot that I know of-
Northern hard maple
Silver (soft) maple
Ipe
Jatoba
Purple Heart
Ash
Hickory
White oak
Red oak
Ipe
Greenheart
Locust (they aren't sure on variety and I've no experience)
He has been trying to get Osage for about 6 months but can't get any of decent length (pen blanks basically).
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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.
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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.
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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.
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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 ?
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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.
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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
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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:
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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. :)
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Acer saccharum
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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.
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
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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.
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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.
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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.
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Thanks for your most recent reply, adb. It was just what I needed to make a decision.
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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.
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I've made several birch bows and they are fine bows, all in the 50# range, none wider than two inches at the fades, made a real nice birch backed black walnut bow that was a pyramid profile, real nice and smooth so you can make bows from it although I wouldn't build a warbow with it, bub