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Main Boards => The Bowyer's Bench => Topic started by: kennym on December 05, 2008, 05:06:00 PM

Title: Help me trap one.....
Post by: kennym on December 05, 2008, 05:06:00 PM

Guys, I'm building a Christmas bow ,it is 10 #s heavy right now,narrow limbs ,.003" taper in em.

Can I trap 10 #s off or do I need to just start over?

Title: Re: Help me trap one.....
Post by: PV on December 05, 2008, 05:36:00 PM

Made the same mistake on the second bow off a new form myself today.Had a senior moment on the stack height on the first bow. Planned on 55#.Came in at 65#. Was 67# before I trapped the limbs. Trapping 10# off a limb would be difficult on a wide limb.
I've dropped 10# by CAREFULLY sanding the back and belly with .050 glass.(Sanding block and counting strokes) Twice as wide is twice as strong,twice as thick is 8X as strong.

I'm starting over as this bow has a carbon back and 040 glass belly
Good luck

Title: Re: Help me trap one.....
Post by: Apex Predator on December 06, 2008, 06:23:00 AM

I'd say you ain't gonna make it.  Unless you have some limb width to play with.  I figure a really aggressive trap job can get you 4-5 pounds.  That's the beauty of trapping, good physical weight reduction compared to not much draw weight reduction.  Just my limited experience.

Title: Re: Help me trap one.....
Post by: Dick in Seattle on December 06, 2008, 11:48:00 AM

someone educate me here....   I get the general idea, but I'm not sure what process is being referred to.   What exactly is "trapping"?

Title: Re: Help me trap one.....
Post by: Holm-Made on December 06, 2008, 11:59:00 AM

Be a good experiment to see what trapping does for your design in terms of performance.  
You might not get 10# but if you got 6# you could sand off a few pounds by flat sanding the glass.  A 60# bow is easier to get rid of then a 65#er so your not really out anything..  

I always lose a good 3# by just rounding the edges good.

You can also try narrowing the limb from the fade up 10 inches.  This will reduce weight in a hurry as that is where most of the stress is in a drawn bow.

Title: Re: Help me trap one.....
Post by: PV on December 06, 2008, 12:41:00 PM

Dick
 Trapping is reducing the sides of the limb from a rectangle to a trapezoidal shape.

              back
               / \\
              belly

 This is the most common way but some bowyers reverse trap from belly to back

Title: Re: Help me trap one.....
Post by: Apex Predator on December 06, 2008, 01:05:00 PM

(http://i121.photobucket.com/albums/o203/Apex-Predator/Apex%20bows/AP00808-5.jpg)

Photo of the last 14" of my limbs.  This is the belly.

Title: Re: Help me trap one.....
Post by: Dick in Seattle on December 06, 2008, 08:27:00 PM

OK... trapezoiding.... what I did to get to the desired weight on my Hill blank.

Thanks

Title: Re: Help me trap one.....
Post by: kennym on December 08, 2008, 09:08:00 PM

Thanks,guys.
Maybe I'll keep this one to play with for myself and make a new one for the Christmas present!!
  :goldtooth: