explain "trapping"

[TroyH]

Can someone explain what is meant by trapping the belly or back, and how is this done on a glass bow that is already formed?

[Frank1107]

I'm no bow builder but I think it refers to the trapezoidal shape given to the limb edges to achieve the desired effect. It is done with a rasp or file. But I ams sure there will be experts who will give you all the details.


Frank

[Pat B]

Trapping is used when you want more compression strength or tension strength.  Frank was right. It refers to the cross section shape(trapezoidal) of the limb. On wood bows((I don't build glass bows), woods that are compression weak can be built with a belly that is wider than the back, thus increasing the compression strength for that bow. On a few of the boo backed bows I built I realized once I started tillering, that the boo was overpowering the belly. I opted to rasp the sides so the back was narrowed than the belly. This decreased the tension strength for that bow and it only took a moderate amount of set.
 I know trap cross sections are used with some modern glass lam bows but that's for someone more familiar with glass bows to explain.    Pat

[Lonesome Wind]

I trap my glass lam bows from back to belly. Meaning that the back is narrower than the belly. I use a progressive trap, going from 1/8" narrower per side at the fades to no trap on the tip. The majority of lam bows are trapped the other way, belly narrower than the back. Trapping this way is easier to do since you have less risk of ruining the tip. I feel the trap I use gives a smooter drawing bow with better cast. Everyone has there own opinion, that's just my two cents.

[TroyH]

Ok, I'm making preparations to make my first glass lam bow.  Are all glass bows trapped, and is it necessary to trap one either way?

[TroyH]

Another question that I meant to ask, how does trapping the limbs affect draw weight, or does it?

[Apex Predator]

It affects very little in the way of draw weight, but reduces weight.  Reduced weight equals greater performance and less shock.  I trap all my longbows on the belly for about 14" towards the tips.  Here is a photo of my latest.  The light is hitting it just right so you can see the trap.

[Trux Turning]

Not all bows are trapped-you will find that some people trap belly to back/and others back to belly- on your other question, trapping will reduce the draw weight.

[Lonesome Wind]

You don't have to trap. You can just round the sides & have a very nice shooting bow. I feel trapping improves the shootability of the bow. Remember this though, you can make a nice bow look pretty shoddy with a poorly done trap. You have to make sure to keep the sides even & the same taper.

[b.glass]

I had to have this explained also. I've done it but didn't know about the slang term.

[Roy Steele]

PAT
  Your right.If you round your limbs.Has the same efect on all wood bows.