Need Bow Form Help!!!

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Need Bow Form Help!!!

Postby Python014 » Fri Oct 31, 2014 11:24 am

Ok I just finished sanding my bottom form and made it look all nice and pretty. Then I got my template back out to double check everything and I made a depressing discovery. It appears that my center line was not 100% straight. So it like the bow would sit uphill inside the form. I think it would be an easy fix by redrawing a center line and shift the whole bottom the the right just a bit. I would only have to recut a little and it all should work out pretty good. Now my concern is the top half. I didnt use a template, instead I just used a 3/4 and 1/2 scrap. So now im not sure how to recut the top half to match the lower. The form is for a 60in recurve btw. Any ideas?
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Re: Need Bow Form Help!!!

Postby Jumpster » Tue Nov 04, 2014 9:06 pm

As for the fact that the bow sits "uphill" while gluing it together; I'm not sure that I'd worry about that so much. Keep in mind that I, myself, am also a beginner; however, I do know how I have done things the first couple of times that I've done them...

Although your Center-Line may not be straight, so long as the limbs are as expected, I'd leave it alone. "Why?" do you ask? Because what I have learned, during my first four bows, was during glue-up, the limbs most definitely need some serious assistance in order to stay in place before the air-hose applied pressure. Hence, masking tape!

During glue-up, I have learned to use "lots" of tape - it is cheap - in order to hold the limb pieces in place before the air-hose is applied! So, in this respect, up-hill vs. level glue-up makes no difference to me. Of course, I'm no expert on these matters...

However, should I be to late with this response, I must say that I've already had a similar experience. That is where I didn't like my "lower" form and made adjustments to a point that I didn't know how to finish the "upper" section.

Then, I realized that, the upper section wasn't nearly as important as the lower section. That's when I focused on perfecting my lower section... Why?

My form uses an air-hose at 60 PSI to hold things in place during curing. Note: this was after SEVERAL other failed attempts to bypass the air-hose. Needless to say, none of them worked - as well... !

So, how did I fix it? The "upper" section?

After "perfecting" my lower section, I took the upper section and tried to cut it down (by nearly 1/3'd) in height. Width wasn't an issue for me, but height was. This was because as I was tweaking the lower form, I ended up widening it up a bit. My initial cut of the top section was wider at the top than it was at the bottom. By cutting the lower 1/3'd off of the bottom, I was able to accomodate the widening of the lower form section.

The thing that aided in this adjustment was the fact that the top section didn't need to be perfect; so long as the gap was relatively consistant from one limb to the other. About a 3/4" gap (give or take a bit) across the bow should be enough to house the pressure strip and air-hose with an even distribution of air-pressure across the entire length of the bow.

Suffice it to say that my top section doesn't look anything like the bottom section, but when the two are put together, the job gets done. I hope this helps!

Regards,


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Re: Need Bow Form Help!!!

Postby Greywolf » Sat Jan 24, 2015 7:32 pm

The top half just keeps the air hose in position and keeps pressure on the lower part of the press the lower section, this is the section makes the bow and the shape you want.

I'm not for sure if I read the issue correctly. but it sounds like the center line wasn't "level" as long as the bow matches the pattern your ok.
Like I said I'm not for 100% sure if I'm understanding the issue.
Lets say you measured for your center line 5 inches on one end and you accidentally measured 5 and 1/2 inches on the other end and drew a center line using this measurements, but your pattern was drawn using the center line and matched on that center line, then it'll be fine.
A straight line is a straight line, level or crooked a bit.

I have modified my top section of my form 2 times, I cut out a section for a different riser pattern using the same bottom form. I just screw the cut out sections back on to the top form and march on forward.
You never get a second chance to make a first good shot Greywolf

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