Does some woods hold heat longer? & bow build

[superdav95]

If the hickory comes in lighter in mass and less set. We may have a new kid on the block.

Careful there! Someone I know once said, "Well I'll say!!  Osage is king!!"

 

Lol I was wondering when some one was gonna catch that!   

[Selfbowman]

Osage still is the King until Its not. 4th heat session. Getting there.

[Bob Barnes]

Hang in there Arvin...but I have an abundance of hickory here on the farm, but no osage...so I'm kinda hoping that we figure out a way to make it (at least) almost as good... 

[Pappy]

I also have lots of hickory on my place and no Osage, in my early years I use to trade 2 or 3 to 1 for Osage, I have several kinds of Hickory but pig nut seems to be the best for me.  :)Looking good Arvin. 
 Pappy

[superdav95]

Same here pappy.  I’ve got lots of hickory and no Osage.  The hickory I have most access to is shagbark variant.  I find it to be little denser then the pignut up here.  It also has a heartwood that is quite hard too.  One day I’ll make a heartwood shagbark bow backed with boo.  Should be good I suspect. 

[Bob Barnes]

The only two varieties that I'm sure I have are mockernut and bitternut.  I know there's no shagbark on my farm, but there may be other varieties.  It all seems hard to split. 

[Selfbowman]

Starting to bend on floor tiller. Getting the clamps to go away. About 3-1/2” told reflex.

[Selfbowman]

Pic

[Selfbowman]

Ok hopefully this is it on the caul. Heat treatments complete!

[Jim Davis]

I also have lots of hickory on my place and no Osage, in my early years I use to trade 2 or 3 to 1 for Osage, I have several kinds of Hickory but pig nut seems to be the best for me.  ...
 Pappy

The Forest Products Laboratories data agrees: Pignut hs the best numbers.

[Selfbowman]

Well it went from53% humidity to 93 % so I guess Arvin’s patience will be tested for the next 4-5 days! .

[superdav95]

I also have lots of hickory on my place and no Osage, in my early years I use to trade 2 or 3 to 1 for Osage, I have several kinds of Hickory but pig nut seems to be the best for me.  ...
 Pappy

The Forest Products Laboratories data agrees: Pignut hs the best numbers.

This is interesting jim.  I’ve read a few articles that suggest the same.  Proper Heat treatment is key for both variations regardless.    My personal observations and testing has revealed that shellbark/shagbark variety makes just as good of a bow or even better as far as heat treated bow is concerned. Raw dry wood may not tell the whole story here.  I know this may go contrary to the research but I have made many of both variations as I have lots of access to both pignut and shagbark here.  I have found that the pignut is less dense and less hard then my shagbark that I’ve got access to.  Do the particular shagbark trees I have access to have more density for some other reasons?  Maybe. Could results vary depending on locations and conditions?  I believe so.    I don’t have a janka meter or a scientific way to measure this as far as hardness goes but the mass of a bow made with either wood I see different performance results and set.  Not a significant amount but some.  I find that the shagbark when heat treated deeply doesn’t check and crack as much as pignut also.  I’ve taken two staves one of each cut the same day and left for a year to season and dry.  Both worked down to rough bow dimensions and clamped to a form and get less checking on the shagbark for some reason.  This didn’t make sense to me either as you would think that the denser shagbark would hold moisture longer then the less dense pignut.  I wonder if the lignins and pectins levels in the shagbark are higher??? When I do a deep heat treat on my hickories I’ve noticed that there is a residue or almost a darker syrupy Color developed at the grain run outs where the tapering or narrowing and also at the ends of the limbs.  Sometimes can even see and hear the steam escape when heat treating.  Is this an indication of more lignin and pectins in the wood?  Maybe.  Anyway I’m rambling here a bit but things I’ve wondered about speaking of hickory in particular and what I’ve seen.  In fact I’d go as far as to say that I’ve noticed more similarities between my shagbark to ironwood/hhb when finished out as a heat treated bow.  The shagbark is obviously my preferred wood of the two because of the ability of getting nice straight staves.  Hard to beat in my opinion.   All anecdotal I know but still observed.  Fwiw.   

[Selfbowman]

Dave have ever built close as you can to the same dimensions then check mass weight of both. Maybe cut some sample pieces and weigh the samples. Ring thickness could also weigh in on the mass. With Osage I have not tested the thick late rings but if you can see the lunar rings it does not seam as dense. 

[Jim Davis]

As you observed--anecdotal.

The problem is that there is probably more variation within a species than there is in the averages of the two woods.

FPL did a great many tests of each species and used the best equipment available at the time.(1920s, IIRC).

Our best hope of getting accurate results would be to test for specific gravity. A stick of any cross sectional shape, uniform from end to end and marked in 10 divisions can be floated vertically in water and the number at the water surface noted. Of course, divisions between the 10 major divisions would be needed and the accuracy of those marks and of observing the water level would affect the reading.

And, the wood samples would have to be at the same moisture content.

Other than that, most our experience with set and bending strength may well be due to that variation from one stick of pig nut to another.

I have several species of hickory on my land, bur have only used shag bark, because those were the trees I wanted to remove, for one reason or another.

[M2A]

Thanks for the time to show the process here first off .But silly question time. All those shims between the stave and the caul? Is that your way to try and remove twist? And does it not allow for heat to wrap around and give a better chance to over heat the back of the bow? Always wanted to ask. And I'm sure the answer is simpler than I think. Thanks.
Mike