Trapping a fiberglass back

[IowaHedge]

Need to reduce as much weight as possible from a fiberglass r/d 66" bow that is to much weight to comfortably shoot. Not sure of thickness of any of the glass or core. I bought what I was hoping a 50lb blank. Think it scaled at 65lbs. Tiller looked good @ 28" and while i "could" shoot it. Would prefer a more comfortable weight. Anyone have a picture of what a trapped back looks like. Ive read several posts about the process and understand the risks/process. Just never done it before and not sure how deep towards the belly i need to go. All the way from back glass to belly glass and then round all the sharp edges away. or back glass to about 1/2 to 3/4 through the core wood.

[Bowjunkie]

That's a lot of weight to try to lose. How wide is the bow now? Maybe you could narrow it before you trap it? The ones I just checked are 70# @ 28" and 1 5/16" wide at the widest part of the limbs.

I trap them about 95% of the way, as viewed at mid limb, and it gradually becomes less trapped as it nears both the tips and fades.

Also, it's not a flat angled trap when it's done, it's a convex arc across all wood lams, and then the edges of the glass are used to finish rounding off the corners. Yep, an arc'd trap with no flats or corners.

I tried to take pictures but it's impossible to see what I'm talking about.

[IowaHedge]

Well after some figuring I think I was calculating my draw length on the tree wrong. So with a  little figuring out and not knowing technical terms I got a arrow out that Is at the draw length I shoot at and figure from where the riser lays on the tree to how far the base of the nock would end up at if I was drawing the bow.  So to start it wasnt 65lbs but 60. I took a file and careful went from were the thickness of the riser fades out to the tip and at a 45 degree angle went there the back about a 1/16th of a inch and just down to the bottom edge of where the glass meets the core. Once it was filed I went over everything that was filed with 120 grit and blended the edges in. Didnt really take much off.  Then I put it back on the tree and its at 55ish now. Wondering if i can take anothe pass with the file for what will end up being a bit larger larger "arc". Ill try to post a picture of the tiller and work so far, but Im not to savvy with posting pictures.

[IowaHedge]

Not sure how to shrink images... sorry

[IowaHedge]

Sorry.. Ill figure out how to shrink before I post a image again.  Or is that a ok size?  Kinda a pain might have to actually fire up the desk to do photos

[Bowjunkie]

Yep, you can hit it again lightly with the file, or just sand it some more with 100-150 grit. A little more arc won't hurt it. Mine are curved a little more than what I think I'm seeing in your picture.

[IowaHedge]

Can i go into the core at about the same angle Take more glass and wood or should i just take a bit more glass only with a shallower angle?  Sorry for all the questions. Its really close to being a good shooting weight for me. If I was more experienced shooter Id just leave it and shoot it but need it a little lighter so i can stay constant in my form. If that last picture was the correct size I can post more pictures of the brace and full draw where its at right now.

[BenBow]

The picture size looks good. I'd just sand it which will smooth the edges nicely. Also if you haven't done so already you should sand the glass with 220 or 320 grit to take off the release agent used in making the glass so your finish will adhere. That could take off a couple of pounds by itself.

[macbow]

Also yes you could take it into the wood laminate as much as 1/2 the lam.
I would suggest using just sand paper on a block from here on.

[IowaHedge]

Pictures a little crooked had to take it myself and dont have a stop to hold the draw.  This is after the trapping I already did. I dont think it looks to bad and thinking using the methods you guys suggested even removal on both limbs again. Let me know what you think. Thanks again for the help

[IowaHedge]

Got unbraced and brace picture also if needed

[BenBow]

If you take more off I'd do it only on the outer half or more likely the middle third. It's bending a lot right off the fades

[IowaHedge]

Well after a few hours of sanding and trapping. Heres were Im at pretty sure the tiller could be better, but I had to post the picture to get some input on the tiller.  Its pretty much as narrow on the limbs as I willing to risk since I dont know how thin they can go before problems happen (currently just a hair under 1 5/16" tapering to 1/2 tips) not trapped to aggressive on the back right now. Wanted to get some input and fine tune the tiller if I can/need to.

[BenBow]

I like mine 1 1/16" at the fades and 7/16" or less at the tips. Unless you have a radical reflexed limb you don't need the width. It's just added weight. Width is heavier than thickness needed to obtain the same draw weight.
Bow looks good!

[IowaHedge]

Its a fairly mild r/d. Think I could go a bit thinner on the limbs?  Sorry for the blurry picture still working on my resizing images for posting

[BenBow]

You might loose 5+ lbs if you go as narrow as I do. Narrow has it's rewards in less hand shock and more speed.

[IowaHedge]

Got it done ( I think) cant get a picture resized to one that isnt huge for some reason tonight. Thank you for all the help. Went with limb narrowing to about 1 1/8" and slightly trapped/rounded back.