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Main Boards => The Bowyer's Bench => Topic started by: tsriberio on March 17, 2020, 01:21:27 PM
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I just finished (90%) building my first set of takedown limbs for a purchased riser as my initial foray into bowyering. In traditional fashion, I am getting ramped up for the next build prior to fully finishing the first.
I noticed that, during glue up, I did not achieve an even distribution of pressure with just a strip of semi-rigid foam. It seems that the fire hose placed pressure on the center of the foam in a cylinder and left the sides of the limbs with less pressure. The glue-up seemed to go fine and the limbs shoot well, but it wasn't ideal.
I am curious as to what you folks are using for pressure strips (steel, micarta, etc.) and if anybody has any thrifty ideas. I have poked around home depot but it might prove difficult to find something longer than 5'.
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I use .030 steel and have always got even presure, thin enough to conform but stiff enought with zip ties in place & leave no hinge spots !
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I use .030 steel and have always got even presure, thin enough to conform but stiff enought with zip ties in place & leave no hinge spots !
x2 also you need about 1" to 1-1/4" gap between the upper and lower forms, any more than that can cause that problem .
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Where is the best place to find 0.030 steel in lengths >60in?
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I got mine from Binghams I also put green frog tape on them to help if they get epoxy on them , Im sure theres other places to get them to !
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Big Jim Bow Company
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Check with a heating co and see if they have any ductwork they can cut a slice from. Needs to be flat tho, without the little creases ...
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A well equipped tinsmith shop usuallly will have large sheets of galvanized thin steel and tools to cut to excact width.
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My experience with those thin strips is one time where epoxy gets on them and you have to really pull to release it, you can deform them and they are useless because you will never be able to get them flat after that. I quit using them and honestly have had 0 issues and I've built a lot of bows.
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My experience with those thin strips is one time where epoxy gets on them and you have to really pull to release it, you can deform them and they are useless because you will never be able to get them flat after that. I quit using them and honestly have had 0 issues and I've built a lot of bows.
So then is the true solution to "domed" limbs having the right amount of spacing between the halves of the form?
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I forgot the pressure strips once and didn't make any difference.
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I use cling wrap on my form, pressure strip, and fire hose.
The anvil on your vice and a hammer will flatten them out.
30 years of metal fabricating
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I use 0.063" 5052-H34 (aluminum) strips with a layer of 3M flash tape to prevent adhesion. The mild temper of the aluminum allows me to roughly hand-bend the fade curves so it's not such a pain to strap down. Haven't had any issues with uneven pressure so far.
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I get the hard rubber glue on base board and band saw it to width. My guess is you have too much space between your top and bottom form
. When the hose is aired up it should take a dog bone shape. So a couple of layers or whatever it takes of the hard rubber to reduce the space there.
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I use paste wax then cling wrap on the press, wrap the hose with cling wrap, I put a thin layer of paste wax on my metal strip, never had any problems
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16 ga. (.062) would be better than the .030
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I forgot the pressure strips once and didn't make any difference.
Really?? That just can't be... :laughing:
The only use I see a pressure strip for is keeping the hose off of the lam keepers and from resin maybe squeezing onto the bow...
Can someone tell me what is the purpose of them??
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If you dont like them then dont use them. It aint a law. I dont see no reason for a raincoat except to keep you from getting wet.
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I could care less, one way or the other... Just never used them... How can you like or dislike something you never used?? So what is their purpose Stic?? Enlighten me ol' master of the great raincoat riddle... :goldtooth:
Actually about a year a go I thought about using them to keep glue off the belly of the bow..
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It's to keep the rain off the glass.
pressure strip, something to put the pressure on.
Like I said, I think 16 ga would actually do what a pressure strip is suppose to do, keep it flat.
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I could see using the strips if you were clamping and such to even out the load but an air hose has close to equal pressure all through it... It should all lay flat with air...
It could be one of those things that everybody used pressure strips back in the day and when they switched from clamps to air they forgot to drop the strips then it was MSMD all after that and never been questioned...
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So what is their purpose Stic?? To keep it flat. Although if your spacing is not right the strip wont do you any good. If ya can do it without the strip fine.
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I read somewhere it was used to prevent cupping of the lams lenghtwise in a tight recurve section of the limb. I guess for the hose to have a smooth surface to glide on.
I use glass that is sanded on two sides, not like the Botuff and BP so if I do not use them a slight pattern from the hose is visible after pressing.
Also if some dried glue spots is on a hose there will be a hard spot there that could press a bit harder than the rest of the hose. Such glue spots are difficult to cut off or remove.
Probably a good idea to wrap the hose in saran wrap.
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Ok... I think I see what you are talking about... It's about keeping the cross section flat... Right?? Makes sense... Thanks guys...
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:clapper: