Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on February 24, 2018, 04:29:13 pm
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My backing strips are 4' long so I have to join them. I was thinking "Z" splice but when the strips are just over 1/8" thick that doesn't make for much gluing surface. Is a flat scarf the best method?
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If you are making a rigid handle bow, you can just butt them together. Then if it makes you feel better, you can glue an overlay on the back of the backing at the joint. If you use a Z or WW splice, there will not be much of the splice left after you narrow the handle.
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A butt joint or scarf joint is plenty sufficient especially if an overlay is added like Jim said.
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I guess a butt joint could work. I have used a 2" long splice, chiselled and then hand planed down flat, just to give the join a little more integrity. I used TB 3. The bows I made like this were essentially stiff handled but must have had some stress into the handle, because the join started to lift. Glued on an overlay and wrapped with string soaked in epoxy. Works really well.
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Put a 45degree angle on your but joints and glue together with super glue. The angle can be achieved by a 1x2cut on 45 then put your laminate next to the 1x2 and grind your angle on a belt sander. Arvin
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You can also glue up each limb separately. Then join them together with a Z splice. Like a billet self bow.
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This is how I do it when I am using 2 backing strips on a deflex handle
(https://i.imgur.com/0fQG0ts.jpg)
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Am I seeing an extra layer in there Marc. I see the two backing strips and then a continuous layer and then the billets. Is the middle one an overlay to strengthen the splice? Do you steam the ends of the backing strips?
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That looks like a power lam to me
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I thought a power strip was on the belly side, but I don't know.
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Typically the power lam is glued between the backing strip and the belly wood
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Put a 45degree angle on your but joints and glue together with super glue. The angle can be achieved by a 1x2cut on 45 then put your laminate next to the 1x2 and grind your angle on a belt sander. Arvin
Wouldn't this be considered a scarf joint?
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Put a 45degree angle on your but joints and glue together with super glue. The angle can be achieved by a 1x2cut on 45 then put your laminate next to the 1x2 and grind your angle on a belt sander. Arvin
Wouldn't this be considered a scarf joint?
I guess so but no matter the name would it not work. After all it's just to hold it together during lay up of the bow correct? Or maybe I misunderstood the?. Arvin
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Typically the power lam is glued between the backing strip and the belly wood
Thank you, I've learned something new today. Now I don't have to think all day ;D ;D
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An overlay can be made with left over backing material then blended into the backing. No wrap needed in a rigid handle bow. If it was a bendy handle them I'd add a wrap.
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Am I seeing an extra layer in there Marc. I see the two backing strips and then a continuous layer and then the billets. Is the middle one an overlay to strengthen the splice? Do you steam the ends of the backing strips?
It is a power lam and I always use them on spliced bows. I use dry-heat on Bamboo and localized steam for Maple.
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Marc, is your power lam spliced also, or is it one piece?
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Put a 45degree angle on your but joints and glue together with super glue. The angle can be achieved by a 1x2cut on 45 then put your laminate next to the 1x2 and grind your angle on a belt sander. Arvin
Wouldn't this be considered a scarf joint?
I guess so but no matter the name would it not work. After all it's just to hold it together during lay up of the bow correct? Or maybe I misunderstood the?. Arvin
Yea, absolutely it would work. Just wanted to make sure we were all on the same page.
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Splicing the power lam would defeat its purpose
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DC, Here is one way that worked for me when I just needed a bit more length.
I either mill a handle block to a deflexed angle or glue up several 1/4" or 3/8" lams of the same wood into a deflexed curve. ))), like that. Add your core, or do your butt-splicing like Marc showed. Power-lam if you plan on it.
The backing can then be glued on with a gap of up to several inches (@ 4" was my biggest), between them depending on how deflexed the whole thing is. You grind the front flat which tapers down the backings just at the tips. Then slap a couple of front overlays on to round out the handle.
If the backing has it's full thickness well inboard of where the fade-outs end, you'll be fine. It's held by several well glued down inches AND sandwiched by the overlays, and supported by the powerlam.
It's worked for about 6 bows for me, so far.
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backing ends at the yellow arrow. Fade on the belly ends at the blue arrow. Power-lam ends at the red arrow.