Primitive Archer
Main Discussion Area => Bows => Topic started by: Blaflair2 on July 09, 2014, 02:48:18 pm
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I understand what it is and all my question is what the best way to make one? How thick? I have a belt sander. Any build alongs which show how? Thanks fellers
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The thickness depends a lot on your belly lam thickness. The main purpose I use a power lam is to stiffen up the handle and in some cases induce deflex at the handle. I would say you want your thickness between belly lam and power lam to equal about 3/4 before the bamboo is added. If you are going less than 60" long you could probably drop that to no less than 5/8. As for making it the main thing is to use a very long taper on the ends of your lam that go to a feather edge. When you think you have it right place it on your handle then see how much effort it takes to push your backing down for a perfect fit. I like to be able to push my backing down for a perfect fit with just moderate thumb pressure.
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Not to hijack this thread, but - - is there any reason why the power lam could not be placed in between the belly and the extra handle piece? In this way, the feathering could be done after glue up as a part of the tillering? Could also look pretty cool, depending on the colors used. What say you all?
Russ
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I would say 1/8" thick, maybe 3/16" and probably 16" long for 64-68" NTN bow. Shorter bow shorter power lam... Do a nice gradual taper on it and you should be good to go. Use hard wood Maple, Hickory..etc. ? One thing I have noticed is using a power lam I'am not touching the belly wood at all. Just doing a width taper, makes life easy I think, but that depends on the design. I usually glue the P.Lam on the back. If I built a forward riser bow I would glue the lam on the belly side.
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I'll be gluing it between the boo and ipe
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I would say 1/8" thick, maybe 3/16" and probably 16" long for 64-68" NTN bow. Shorter bow shorter power lam... Do a nice gradual taper on it and you should be good to go. Use hard wood Maple, Hickory..etc. ? One thing I have noticed is using a power lam I'am not touching the belly wood at all. Just doing a width taper, makes life easy I think, but that depends on the design. I usually glue the P.Lam on the back. If I built a forward riser bow I would glue the lam on the belly side.
A power lam is not a power lam unless you glue it between the back and the belly lams
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It works the same way does it not if glued on the outside. ??? Sort of
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It extends past your fades, so if it were on the outside it'd pop
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Titebond is stronger than the wood itself. :D Proper glue up nothing should pop. Its just aiding the fades, if all is well the area will stretch under tension like its supposed to. I have seen other guys do the same thing. Anyway time will tell I have a couple that I made like that. As a matter of fact the last one broke but the lam did not give one iota and the handle did not pop... ;D
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No it WILL pop for certain.
The whole point of a powerlam is to go between back and belly lams to stop excessive bending near the fades without having to use a thick belly lam that ends up being mostly on the floor. Powerlams are almost always the length of handle plus fades plus 2 - 4 inches per each limb. Mine normal are 18 inches.
As Badger says make your taper long and the ends should be paper thin for an inch. You should be able to see light through them.
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I understand what it is and all my question is what the best way to make one? How thick? I have a belt sander. Any build alongs which show how? Thanks fellers
To answer the actual questions addressed here: a belt sander is the way to go. First cut a slat of wood with a (table or band) saw. I cut the power lam 18"x2"x3/16". But a thickness of 1/8" or 1/4" will work as well. Then mount your belt sander upside down, so it becomes a stationary belt sander. Use a small block of wood to press down the end of the powerlam onto the belt. Like this:
(http://www.zelfbogenmaken.nl/site-fotos/bogen/nick%20fennema/buildalong-nick/Afbeelding14.jpg)
The dark ipé in this picture is just to keep your finger away from the belt. It's the lighter colored maple lam that will make the power lam.
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Hasn't Bubby done "power lams" as a belly lam, not sandwiched between back and belly?
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Well I glued it up. Without a power lam ::). I couldn't get it into a smooth transition. Well see how it ends up. Thanks all. I understand how to make one at least now
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I have done what you said but its not really a power lamp it's basically just a built-up laminated handle so that your handle didn't bend, I wouldn't call it a power lam, there's more than one way to accomplish this and get the same results but I wouldn't call them all powerlams
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I'm gonna see how stuff it is after I take it out and clean it up. I may try gluing super thing pieces to do like bubby says. I figure a couple 1/16" lams feathered in May hold. if it doesn't need it then I won't. But I do have some pretty woods
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I have done what you said but its not really a power lamp it's basically just a built-up laminated handle so that your handle didn't bend, I wouldn't call it a power lam, there's more than one way to accomplish this and get the same results but I wouldn't call them all powerlams
Ok - - i agree that we do not have to call it a power lam and that it would be more appropriate to look at it as an additional built up handle piece - - but if this extra piece extends well past the remainder of the handle - - well past the end of the fades - as in -- the same length a power lam would be - couple inches past the end of the fades on both sides --- do you think it would serve to stiffin the limb or would it pop since part of it will be in a bending section of limb?
I am leaning towards thinking it will still pop - like Mike says. Since I already glued one up like this without thinking it through - the best thing to do it feather it back completely so that it is just a built up handle? Thoughts?
Russ
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I don't think you'll have a problem with it popping as long as it has a good mating surface
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Alright - we shall see. I will keep it long and see what happens. I will report back in 10 days or so. I will try to get a pic up too.
Russ
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I don't think you'll have a problem with it popping as long as it has a good mating surface
Thanks for chiming in bubb, ...... I have worked and been trained from some masters wood workers and the agreement is Titebond is stronger than the wood itself. :D. I guess what I'm trying to say is the area may FAIL under continued stress and break rather than POPPING off like coming apart at glue glue seam, which is likely as Bub says "as long as it has a good mating surface"
I hear you's about the P-lam been sandwiched. I won't go there again, so there..........I'm really upset now..... :-[ >:D
I have done what you said but its not really a power lamp it's basically just a built-up laminated handle so that your handle didn't bend, I wouldn't call it a power lam, there's more than one way to accomplish this and get the same results but I wouldn't call them all powerlams
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Handles pop all the time even with perfect glue joints, even with urac thy can pop off. It's always best to eliminate most of the flex in the handle before you glue on a solid piece. It doesn't pop all at once, it starts at an almost microscopic edge with a huge amount of stress on it and then spreads almost instantly.
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I speaking of glue joints >:D if I have a few gaps think it would be ok? Were talking small, I think it'd be ok. I havent cleaned it up to final dimensions so I think they will disappear, most of em
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I find that if the power lam is too thick then you can have problems with the transition when it reaches the core. I keep mine to no more than 1/8" thick
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I have done what you said but its not really a power lamp it's basically just a built-up laminated handle so that your handle didn't bend, I wouldn't call it a power lam, there's more than one way to accomplish this and get the same results but I wouldn't call them all powerlams
Like Bubby, I rarely put the powerlam in between the belly, and back. I have made R/D recurves by simply adding a 1/8 slat that extends slightly longer the the actual handle, and just feather everything in. Titbond 3.
VMB
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We call them power lams but in reality it was developed for glass bows to move the bend away from the riser and gain some control over where the bow started its bend. Most all glass bows either use a straight taper or paralell even thickness limbs. A reverse taper in the tips and a power lam allows them to place the bend where they want it. Wood bows are different, we just tiller them into the shape we want. Power lams allow is to use a thinner belly lam and save wood. In reality it is just a stiffner for the center of the bow.
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My recent bamboo backed ipé bow (link (http://www.primitivearcher.com/smf/index.php?topic=45380.0)) is a perfect example of that, Steve. The ipé I had was only 10 mm thick. But with the smart use of a power lam, I could still get a very nice bow with very little ipé.
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Handles pop all the time even with perfect glue joints, even with urac thy can pop off. It's always best to eliminate most of the flex in the handle before you glue on a solid piece. It doesn't pop all at once, it starts at an almost microscopic edge with a huge amount of stress on it and then spreads almost instantly.
+1
Good mating surfaces are a prerequisite! Handles popping off are a product of bad design - NO glue will hold a badly designed handle on to a too thin belly lam.