Author Topic: 2 HLD failures  (Read 8740 times)

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Offline simson

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2 HLD failures
« on: January 30, 2014, 03:44:07 pm »
This day was a hard day, two failures on HLD bows. One chrysaled badly, the other exploded. I post some pics, because it is interesting.

The first bow is made of sumach. I always searched for this wood, because I knew it has a fantastic greenish color inside. And some weeks ago I got one. This wood is incredible light almost feels like balsa, my stave was only 4 years old, one ring white sap, 3 rings green heartwood. Full diameter at handle, where the hole of the pith can be seen.
The wood dried out very fast and got light, I decided to go as wide as possible and relative long.
The bow came out 50-55# and shot incredible – but only 20 or so arrows (HAHAHA). Then came down every shot. My examination showed the badest chrysaling I ever have seen. They were everywhere not only on the belly, but also in the outer thirds of the backside (cross section). For those who are interested, the bows mass is only 323 grams!

What have I learned: Sumach isn't a bow wood!!!!!!!!!!!!!!




















The second one is an elder again, this time more a long bow design (71” ntn). It came from a long, nice, and  slight twisted stave. The bow was already done, only some light sanding and finish were to do.
I (idiot!) wanted to know how far it could be bent. Had it on the tree to look at for drawweight, my scale had a mis function, he ld the full draw (30) a second too long – and bang.
This bow was a dream to draw - the smoothest draw! Draw weight was 60 at 28”. Mass is 528grams.
The initial crack is on the back (see pencil point), perpendicular to the limb (upper! > see Del's thread: where do they break?) It exploded with a loud bang and the crack run almost exactly between the first and second growth-ring til it was stopped by the handle wrapping.
What have I learned: Don't play around with a damn digi scale out of order when a bow is drawn!!!!!!





the initial crack where the pencil points















excuse the excessive photostory
Simon
Bavaria, Germany

Online Pat B

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Re: 2 HLD failures
« Reply #1 on: January 30, 2014, 03:48:37 pm »
It sure is beautiful wood. Too bad it doesn't take the stresses of being a bow. It does look like it blew up pretty dramatically, though.  ;)
  If they gotta blow I prefer a dramatic explosion.  ;D
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline lostarrow

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Re: 2 HLD failures
« Reply #2 on: January 30, 2014, 04:10:11 pm »
That's a lot of pieces ;D :( Must be very dry  where you are this year,too. RH of around 25% in my shop right now.

Offline burchett.donald

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Re: 2 HLD failures
« Reply #3 on: January 30, 2014, 04:16:48 pm »
 Jeeeesh! Those were some beauties...I know you put a lot into those.
Genesis 27:3 Now therefore take, I pray thee, thy weapons, thy quiver and thy bow, and go out to the field, and take me some venison;

Offline PEARL DRUMS

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Re: 2 HLD failures
« Reply #4 on: January 30, 2014, 04:18:31 pm »
Id try that sumac one more time with a flat belly before you check it off your list.
Only when the last tree has died and the last river has been poisoned and the last fish has been caught will we realize we cannot eat money.

Offline IdahoMatt

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Re: 2 HLD failures
« Reply #5 on: January 30, 2014, 04:44:25 pm »
That's too bad man.  Even your failure bows look amazing.  Did you toast the belly on the sumac?

JacksonCash

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Re: 2 HLD failures
« Reply #6 on: January 30, 2014, 05:54:13 pm »
Do you know what type of sumac it was from? Staghorn sumac is supposed to be borderline, but I don't know about any other types. I've got tons of the stag horn near my house. The flowers make a great summer drink if you soak them in some water for a while.

Offline Badger

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Re: 2 HLD failures
« Reply #7 on: January 30, 2014, 06:12:18 pm »
 broken or not amazing what you are doing with these bows.

Offline JW_Halverson

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Re: 2 HLD failures
« Reply #8 on: January 30, 2014, 07:05:28 pm »
Broken or detonated?
Guns have triggers. Bicycles have wheels. Trees and bows have wooden limbs.

Offline bubbles

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Re: 2 HLD failures
« Reply #9 on: January 30, 2014, 08:19:20 pm »
Interesting to see that the chrysals go all the way across the limb instead of being confined to the edges.

Offline Danzn Bar

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Re: 2 HLD failures
« Reply #10 on: January 30, 2014, 09:06:53 pm »
Wow I agree and explosion I'm glad you weren't holding it when it went?
DBar
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Offline simson

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Re: 2 HLD failures
« Reply #11 on: January 31, 2014, 04:22:36 am »
It sure is beautiful wood. Too bad it doesn't take the stresses of being a bow. It does look like it blew up pretty dramatically, though.  ;)
  If they gotta blow I prefer a dramatic explosion.  ;D

Yeah Pat, I know what you mean. Same for me. They shouldn't go through the back door! ;D

That's a lot of pieces ;D :( Must be very dry  where you are this year,too. RH of around 25% in my shop right now.

In my shop always between 45 - max 60%, I have a hygrometer hanging just below my bows!

Id try that sumac one more time with a flat belly before you check it off your list.

Pearlie, I definitely won't do that. Look at the sg or the bow's mass - that is no bow wood, I should have known that.

That's too bad man.  Even your failure bows look amazing.  Did you toast the belly on the sumac?

No toasting on both bows

Do you know what type of sumac it was from? Staghorn sumac is supposed to be borderline, but I don't know about any other types. I've got tons of the stag horn near my house. The flowers make a great summer drink if you soak them in some water for a while.

Yes , that is staghorn sumac. Don't know what to do with that spectacular colored wood, but as said no bowwood

Broken or detonated?

As said, the sumac chrysaled badly, the elder exploded with bang like a gun shot

Interesting to see that the chrysals go all the way across the limb instead of being confined to the edges.

Yes, that are my thoughts too. Good, you are pointing again on this. Also the elder bow with the initial crack in middle of the back. Wouldn't we expect a failure on the ridges bellyside? I think even that damaged bows are an argument for the HLD. I don't give up, I have some staves left which are suitable for HLD.

ALL:
Thanks for your thoughts and response!
Simon
Bavaria, Germany

mikekeswick

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Re: 2 HLD failures
« Reply #12 on: January 31, 2014, 04:45:16 am »
Yes the failures are the important ones! They tell you for sure what you only surmised before.
The chrysals are the most interesting to me. Yes they go right across (great!) but they appear from the photos to be worst at the edges? Am I right here? The tension break is also a good thing in my eyes it shows that the wood is being made to work properly with reference to it's properties. As in bows normally fail in compression due to (most) woods being stronger in tension. To be fair I haven't done many bend trsts with elder but I would presume its a tension strong wood. On a side note have you ever hada compression fracture with elder?

Offline Marc St Louis

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Re: 2 HLD failures
« Reply #13 on: January 31, 2014, 10:32:31 am »
Too bad about the bows. 

My take on this design is that, although interesting, it is not a viable method of making a reliable wood bow.  Sure you may get some that will survive, for awhile, but unless you are using wood that has a very high elastic modulus then the bow is sure to develop problems, sooner or later.
Home of heat-treating, Corbeil, On.  Canada

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Offline Del the cat

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Re: 2 HLD failures
« Reply #14 on: January 31, 2014, 10:42:00 am »
Real shame, gorgeous bow... but we're just gluttons for punishment ;D
Del
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