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Main Boards => The Bowyer's Bench => Topic started by: Jon LOW on February 13, 2017, 07:29:00 PM
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So I am trying to make limbs for my takedown recurve. I have already tried to glue the limbs twice in the forms that I made, but both times the glue had inconsistent pressure. The second time I had assumed it was a poor form, so I made a new one, and had the same problem.
First this could be due to my methods, right now I have just used my forms and pipe clamps, and that doesn't seem to do the trick. Maybe this could be due to how I made my forms? Any tips? (I will upload a pic soon)
Second, I have seen that most bowyers use a piece of clamped fire hose to evenly distribute pressure. Has anyone tried a bike tire? Or is there a reason the fire hose is preferred?
Thanks in advance for any help!
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You will need something to more evenly distribute pressure using clamps - you need a decent number so you can space them reasonably close together.
I've never tried the bicycle inner tube method, but lots on here do/have.
I've also seen dowels with rope and wedges used, again with a pressure strip to distribute pressure.
Here's a video of the inner tube method.
https://www.youtube.com/watch?v=0a3nhYpq6cY
Here's a link to metal strip & rubber padding.
http://poorfolkbows.com/glass5.htm
I've read that the rope & wedge method is a pain.
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(https://lh3.googleusercontent.com/jITgzAT4Epmjf5vlxvdTcUuTk87SemdZB9_oyrQP1zyq3xLH0Ou1gQ8EpFXBeTRu9gdgsuw=s151)
This is the form I used the second time, I just clamped it with about 5 clamps, 2 long ways, 3 short ways. Personally I cant figure out how I didn't get consistent pressure, but I know could see gaps in some places, and I didn't like that.
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This is a picture of a DRY run to see if the riser fades and other parts fit and look good before glue up..The "fire hose" in this picture has 60 psi of air pressure. As you can see it fills the space between the top of the form and laminations. There are metal pressure strips between the hose and bow laminations too. The air pressure and pressure strips provide nice even pressure to the bow laminations (http://i596.photobucket.com/albums/tt46/Robertfishes/firstlongbowdryrun.jpg) (http://s596.photobucket.com/user/Robertfishes/media/firstlongbowdryrun.jpg.html)
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If you are asking about using a bike tube AS you would use fire hose I'd say no!
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yeah forget the bike tube, call Big Jim and get the fire hose set up if you want to go that way, works great and its inexpensive.
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Also, the form in your picture is a good candidate for a rubber band form which is where you would use your bike tubes.
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Jon... Are you saying that you put the lams between the two forms and clamped them together?? Everything would have to be supper tight tolerances for that to work... You could probably make that work if you put some dense foam on one of the forms... Your best bet is to just do the firehose deal... Like in Roberts pic... Takes a little investment and effort to make but will pay off within the first three uses...
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I have not used the "rubber band" method but plenty of others have. If you go that route you will not need the top of the form
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Thanks for the advice, I have already found some fire hose and I am now working on that method...
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You will be fine with the hose.
No way using the two forms would work you would always end up with gaps.
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The form in the picture is they type made to use a fire hose, not rubber bands (tire tubes). They are two different bow laminating methods and each has their own use. If you want to use this type of form in your picture you will need to be able to clamp it together with side brackets. Look up Bingham projects. Also this is a fire hose form. A inner tube form a bike is not strong enough. Get the hose and clamps. When you hear of inner tubes being used, they are used like rubber bands with just a bottom of the form not inflated. Good luck.
T