Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on February 17, 2019, 11:28:14 am
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Does anyone have any hints as to how I can end up with a nice glue line on a curved joint like this?
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Patience, (like most bow making stuff) a strong light behind it so you can look for gaps and maybe steam and clamp it, for a near perfect fit. Then dismantle and glue when cooled and dried.
I don't see that the joint is actually curved, isn't it a straight splice, but simply on curved pieces?
Can't really see the mechanical arrangement of the joint.
Del
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These two surfaces are joined. What I did was scrub a piece of carbon paper(boy was that hard to find) between the two and sand off the black spots. Did that until I thought I was close then I used double sided tape to stick sandpaper to one surface and scrubbed the other piece against it. Then moved the sandpaper to the other surface and repeat.
We'll see how it goes after the epoxy sets. I'm still looking for any better ideas. Rocking the block back and forth tends to remove a little more wood at the ends which is the only spot that will actually show. That's assuming I put a leather handle on it.
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nobody said it gonna be easy,, (f)
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A bit late to the party, I would have spray adhesived some course sand paper to the riser block and rubbed it back and forth on the stave to make a matching surface. Then remove the paper and adhesive, with acetone, then freshened up the surface of the riser with paper again.
Your method looks like it will work fine too, if you used a good gap filling glue like epoxy.
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I do this all the time. It just takes patience. I use three hacksaw blades taped together as a sort of rasping scraper to scoop out the stave section once an initial portion is rasped out.
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I like Pat's idea. Never done this though.
Is that plum and yew? (-P
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Hamish- that's basically what I did but I used double sided tape to hold the sandpaper. I think adhesive backed sandpaper would work great.
Pat- How does that help match the surfaces? How do you know where to remove wood?
Upstate- It's all Yew. It's a highly reflexed Yew branch and the insert/riser is a piece of scrap yew. The colors don't match very well though. Here's a poor picture of what I started with. The sapwood is kind of funny looking and there is a couple of big knots that some bonehead(me) cut too close so I'm a little apprehensive about this one.
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How are you able to get the pictures under 250 kb? sorry if its off topic. :)
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I have an old digital camera that I set to 640x480. I use it exclusively for internet pictures. No resizing necessary.
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I personally don't like gluing a thick piece in like that I would recommend using several thin pieces
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Don I did 4 of these riser/belly overlays in the last year different material but same concept, I will tell you how I did it if it will help I start by putting centering marks on both the overlay & the bow center then I put the bow directly on top of the overlay & trace the radius making sure the center marks are centered then I will cut grind or whats available tell no pencil line is visible , I get a directional light (flash light) and clamp the belly overlay to the bow & shine the light on the opposet side you can cleary see the high spots sand those and re fit when you think you have it close , scribe pencil marks all over the jointing surface of the overlay and tape in place on your bow a strip of 80 grit sand paper , match your center marks and shimmy your overlay back and fourth with in 1/4" of your center marks the pencil will be removed from any high spots re sand and re fit tell you get a perfect fit using my system I can do one from start to finish now in about 11/2 hour ! Hope it helped
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Marc- Do you use thin enough pieces so you can clamp them with bike tube rubber? On a previous bow I did use some veneer that I had kicking around but it took a lot of layers, 15 if I remember right. It turned out nice though. Do you think many layers is any stronger than one chunk?
SB- That's pretty much what I did. Basically get it close and use sticky back sandpaper. It worked pretty quickly but Yew is soft wood. I'd hate to try it with Ocean Spray :D
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Oh, I see it now ::) :-[... yeah, what they all said...
Del
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That's the way I do it too DC. Tape sandpaper to the bow, then sand, check, sand, check, repeated a couple hundred times. I shine a light too.
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I guess that's the way to do it :) :) although I'm giving serious thought to the way Marc suggested. I was hoping someone had a real clever solution. I was thinking that a guy could clamp/screw/glue the two pieces together somehow and then run the bandsaw along the join and keep doing this until the saw blade touched both sides all the way along that it might fit nicely. I think this has a bunch of problems that would have to be solved first and I'm not sure how nice the glue line would be.
Thanks for all the input :)
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I do it like Marc suggest too. But sometimes the bend is too much or it's too much of a hassle to try and clamp it.
Most of the FG guys use a pattern sander with a template. I'm not stooping that low though... :).
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Here's the end result roughed out. I'm pretty pleased. :D
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That looks pretty darn good :OK
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I do it like Marc suggest too. But sometimes the bend is too much or it's too much of a hassle to try and clamp it.
I'll bet a guy could quite easily put together a small version of one of those fire hose/air pressure clamps that would work real well in this situation.
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You could easily put together a fire hose clamping system but you would need some type of rigid form made for the bow other wise you would risk torquing the bow in different directions , here is simple solution for gluing up a multi lam riser you could glue up your lams you could put your stack centered on your bow with a Pressure strip on top use a single clamp in the center as you line up your riser lams lock them In place with zip ties wrapped around the riser & bow add clamps & cut the zip ties after all clamps are in place , Sorry Ben another lowly FG bowyer trick :D
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Id say you worked that out just fine.
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You could easily put together a fire hose clamping system but you would need some type of rigid form made for the bow other wise you would risk torquing the bow in different directions , here is simple solution for gluing up a multi lam riser you could glue up your lams you could put your stack centered on your bow with a Pressure strip on top use a single clamp in the center as you line up your riser lams lock them In place with zip ties wrapped around the riser & bow add clamps & cut the zip ties after all clamps are in place , Sorry Ben another lowly FG bowyer trick :D
If you were using something thin like veneer you wouldn't need a whole lot of pressure to push it together would you? Not enough to push a handle out of shape? I've never done air pressure clamping so I know nuthin' ;D
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Don that's a whole different thread on clamping Presure there are a lot of different opinions on it but most use 40-75 PSI when using epoxy but I don't think your lam thickness has much to do with it but if your talking veneer like .030 you would need a lot of lams to make a riser ? 40-70PSI doesn't sound like a lot of Pressure but could easily torque your combo out of place with out some type of rigid form or backing , I only put 31 PSI in my SUV tires but keeps a couple thousand pounds off the pavement the hose clamps put a lot of Pressure on the work !
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I was thinking 10-15 psi would make veneer conform to just about any shape I would have on a bow. I wonder what PSI would be equal to a bunch of bike tube wraps. This is an Ocean Spray with an Ash veneer riser.I just wrapped it with bike tube.
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That's a real tight fit Don, well done!
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That's a good fit. My method would just involve placing the pieces together and noting the high spots and reducing them. This is one of those things that seems complex but after you do a couple it just becomes really easy. Practice anything and you'll get OK at it.
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thats great DC,, looks nice,,
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The glue line looks good but all the rest of it is greek to me.
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That's a good fit. My method would just involve placing the pieces together and noting the high spots and reducing them. This is one of those things that seems complex but after you do a couple it just becomes really easy. Practice anything and you'll get OK at it.
I agree with Pat after a few they become intuitive Don I dont know on the 15 PSI you could lay the hose on the riser stack and wrap it with mule tape tape or you could make a backing peace mirror image of your riser and go with what ever presuere you want only one way to find out 😃
If your only going to 15psi dont invest in a fire hose you could just seal up a intertube cheap those lams look thicker then venere from the pic at 15 psi you might be able to wrap it with para cord ! Could make your whole clamping system for $5 👍🏻
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I agree with Pat after a few they become intuitive Don I dont know on the 15 PSI you could lay the hose on the riser stack and wrap it with mule tape tape or you could make a backing peace mirror image of your riser and go with what ever presuere you want only one way to find out 😃
If your only going to 15psi dont invest in a fire hose you could just seal up a intertube cheap those lams look thicker then venere from the pic at 15 psi you might be able to wrap it with para cord ! Could make your whole clamping system for $5 👍🏻
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Hmmm....para chord, a couple bike intertubes, and a hand pump.....now my wheels are rolling....I'm going to test this out.
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Inner tube has no strength integrity when not supported by a tire. It will just balloon all over the place, even a few PSI.
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Inner tube has no strength integrity when not supported by a tire. It will just balloon all over the place, even a few PSI.
I was thinking that too. But I have some ideas that may contain it.
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Just wrap it completly so the tube has no where to go like a cacoon ,Im just not sure about using only 15 psi the lowest presure even for the low presure guys is 40 psi is the minimum !
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Heck if your only going 15 psi try duct tape or gorilla tape :P
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Most bike tires go higher than 30 psi. You can get that with a hand pump.
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Sure it's easy to make up some sort of containment system, I was just cautioning against thinking the tube alone would hold any sort of shape by itself.
You can go well over 100 psi with a simple bike pump.
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You could easely make a ruff short form of the riser area tracing the back of your bow similar to the pic nothing to fancy put rubber striping to take up any inperfections in the natural material on the form put your hose on top of the overlay & lace it down with mule tape or para cord if you wanted a legit fire hose and air valve probably $25 for the set up ,you could make the form maybe 1 hour and you could go to a proper presure with no worries ! If you want to stoop to it Ben >:D
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Years ago I used to build a flat block out of plaster paris around the area I was going to splice. I would then tape my pattern to the plaster paris and cut right through it with my bandsaw, I have also done it with a big gob of flour dough but it takes a long time to dry. With the flour dough I just let it dry then sand it flat before putting on my pattern.