Primitive Archer
Main Discussion Area => Bows => Topic started by: Marc St Louis on June 11, 2008, 11:21:15 am
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Tonka is a SA tropical hardwood that is very heavy and has very high compression strength. I had been wanting to try this wood and I got enough from Steve Quinton a couple years ago to make a bow. I backed it with Bamboo in a R/D style and have been working on it a bit now and then. The bow was 60" long and 1" wide and in the last couple weeks I tillered the bow out. I had it tillered out to 27" where it was pulling 65#, I should have quit there. When I pulled the bow to 28" the core let go in a very odd manner. The failure was not violent, in fact it was almost in slow motion. You can see what happened in this picture
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Mark, this seems to be a common problem with a growing list of tropical hardwoods. They are very strong then suddenly chrysal. I have gotten gun shy about experimenting due to my wallet not having an endless supply of money in it LOL. Steve
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Bummer, looked like it was shaping up to be a real nice one. Shame that tonka wood isn't as tough as those Tonka trucks I had back in the day. :)
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Steve
I was amazed at how strong the wood is. The failure was not your typical chrysal
Well that being the case maybe we should look into making bows with those Tonka trucks :)
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Mark, hard to see what happened, I thought it was a chrysal. I have two common problems with tropicals, one is chrsaling and the other is where it just blows out, the grain just seperates in sheer tension and rides up over the grain it was attached to. Bummer either way. What happened on that bow? Steve
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Steve
More like the second failure you mention there. The limb just buckled in on itself.
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For what it's worth, tonka is also known as cumaru.
Tuukka
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Marc,
Do you think the wood would work better if the bow was narrower and thicker?
I had had a similar experience with Ipe when it was very thin?
Maybe a skinny deep bow wood?
Is there enough wood left to try making a skinny bow out of the bits?
Mark in England
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I don't think so Mark. It was already only 1" wide. Perhaps a flat belly might have worked, it was a shallow D section
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Maybe if it were wider/longer? Would that have helped ????
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Higher humidity? Seems like bows made from these woods where originally in jungals.
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That would have helped Kegan.
The humidity up here right now is quite high
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What's high up there Marc? It's 88 percent here right now.
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Most tropicals are too convoluted grain wise to mess with on high performance belly sections. I have access to most where I live and years ago tried many of them, and until Ipe showed up at the lumber yard I had pretty much given up..Satinwood being one of the few exceptions.
Rich
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You got me beat Eddie. Here's it's in the 70's.
There's a few more that work quite well besides Ipe Rich.
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;D I know there is, just relative to the total population of tropicals is what I meant, and some are freakin expensive :o ;D
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On the topic of tropicals, anyone ever use Jatoba?
Cheers,
Grant
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Jatoba works pretty good. Justin
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Jatoba can work pretty well, but don't crowd the tiller too much into a small working area or it will chrysal. I set a new national flight record with a jatoba bow this year. The top limb was actually broken across the belly and the bottom limb had torn itself apart with a dry fire, it was all wrapped in linen string and superglued together, both limbs were badly chrysaled. I was amazed I even got my shots off with that bow. I had only drawn it to about 25" at home cause I wanted to keep it fresh for the flights. Steve
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Any particular design I should go for with it? Make it long and bend in the handle perhaps?
Thanks,
Grant
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in our home-improvement market a tropical wood, called massaranduba (dont know if this is the english name, too), is sold.
some german bowyers made positive experiences with this wood in a d-bow style
next time i can get some i buy something and tell you about my experiences
al fadee
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Al Fadee It's called bullet wood here, and its good for bows.
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Does Satinwood = Yellowheart?
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Yes D. Tiller.
Bummer about your bow Marc. When I'm given a unique piece like that I will try to get a bow out of it even if I know it might blow..Those chrysals are a bit surprising. Looks a bit like my last, and only poplar/boo attempt..It was a little light though...
Rich
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I've never had a bow let go like that Rich. It was an odd feeling. They usually just blow