Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on October 15, 2018, 05:42:42 pm
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Pender Bender gave me a couple of Laburnum billets(thanks Brendan) at our gathering. I've never even seen Laburnum before. A search suggested that some of the sapwood should be removed but it wasn't that clear. It sounded like the outside sapwood is suspect but a few rings in it's OK. Can someone clear this up?
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I've never used it but I've seen some beautiful Laburnum bows, seems most from across the pond.
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I'll have to take some pictures. The sapwood looks a little grey so I'm going to want some opinions of it's health.
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Hi DC
I have some laburnum resting in my stock pile until after I've learnt to build bows...
In the meantime I've read as much as I could about it and talked to more expirienced bowyers: I've read that experiments have showed that the sapwood isn't better in tension than the heartwood. The bowyers I asked told me, that they never use the sapwood as long as the stave is thick enough to build a bow without. I've seen some laburnum bows but never one with the sapwood on. I therefore think it's a similar sapwood-situation as you have with black locust or osage. I've also heard that the sapwood tends to dry out and the durability is suspect in general. So much for theory...
I therefore removed all the sapwood from my staves.
Cheers, lucky guy
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I've used it for a crossbow prod, sap wood removed, taken down to a ring.
Tried for bow, but there was rot in there nd it exploded, it was a tree that had died in our garden, so the root end wasn't sound.
Nice looking wood, I've kept the rest of it for low stress applications.
Del
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DC, laburnum sap has a tendency to rott. So remove every sap what looks not good, grey sap mostla have already a fungus in it.
Laburnum works also with heart wood only, but it looks great in the combo. When combo make sure the heart wood is at least 2x thick as the sap.
Heart wood darkens to a chocolate brown and makes the nicest contrast to the whitish sap. It is very good bow wood, but hard to get good staves (at least in my homeland). I've made 10 or 12 out of that wood, here are some: http://primitive-bows.com/tag/laburnum/
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I may strip the sapwood off and back it with Boo or Maple. I'll take a closer look to see how straight it is. It looks better in the picture than in real life.
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If the sap is solid I would leave a few rings on. Laburnum is extremely pretty after finishing and even more with the sap/heart contrast.
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The laburnum bows I've seen(here on PA) have all had sapwood intact and were all very beautiful bows.
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I was kind of squaring off the stave and noticed that there seemed to be soft areas in the heartwood. I'll have to wait until the European guys take a look at the pictures but I'm thinking it's no good.
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Laburnum certainly is a very good an elastic bow wood. Iīve made a couple of laburnum bows and Iīm very happy with the results. Iīm using one bow since more then five years and I donīt feel that it has lost any cast since then. Iīve read about an 18th cenury botanist, who claimed that laburnum bows can be used up to 50 years - Iīll let you know about it in 45 years ;)
I usually prefere laburnum bows with sapwood. They do look great and the sap wood is extremely good in tention - maybe a bit better then heartwood, but Iīm not sure. But the sap wood does rot very easily. I have some staves where the sap wood started to rot because the wood was covered with a canvas at first :( The wood couldnīt breath enough. But still, I do have made a bow with sapwood out of one stave and it didnīt break, although there might be some fungus. Speaking about my other staves, I will definatelly remove the sap wood.
In order to see if it still works, you can remove a scale of the sapwood and see if it is still intact. If itīs elastic and tough, the bow will be ok. But you should definatelly remove the sapwood, if it is black, brittle or at least more brittle then the heart wood.
Will the rotten heart wood definatelly be in your bow?
lonbow
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Will the rotten heart wood definatelly be in your bow?
lonbow
I'm not sure yet. If I take all the sapwood off there won't be that much left. Probably enough to make a bow but it will be tight. Does the sapwood in the pictures look suspect to you?
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I think itīs a thin line bethween good sapwood and broken sapwood. So I unfortunatelly canīt tell you by just looking at your pictures. How is the consistency? Is it smooth or brittle?
Maybe you should remove the rotten heartwood at first and see how much wood you have left. If there is plenty, you could remove all the sap wood to be on the safe side. If there isnīt enough wood anymore, you must try and see.
Backing the bow is not an option right?
lonbow
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Backing is an option if I have to. I have Maple and Boo.