Has anyone reduced weight of a bow by sanding the glass faces?

[Jason Jelinek]

I need to reduce the weight of a deep cored longbow by about 5#, the bow is about 65#@28".  The glass is 0.05" thick on the back and belly.

I was planning on putting 150 grit sandpaper on a sanding block and making an equal number of strokes on the back and belly of each limb.  I've made a trace of the bow strung on butcher paper before I started sanding to get a picture of the tiller.

Has anyone done this before?  Is this the right approach?

[Darryl Trimble]

hey Jason, I've done it with good success.  I use 120 grit. to remove 5 lbs your only going to need to work the belly.  Take about 20 passes and flex the bow real good then weigh it and continue in this manner until you have reached the target weight.

[Randy Morin]

Piece of cake Jason.  It will work well.  Mark the end of your fadeouts with a pencil so you can keep track of tiller measurements before, during and when done droping weight.  Shouldnt change much if you count strokes.  Also, its common to put more pressure on one side of the sanding block so switch hands or flip bow around to avoid sanding glass unevenly.  You will only need to sand about .005" glass.  Round glass corners when you are done.  Use light pressure, let the paper do the work and 120 grit or wet 150 if the bow has a good finish (moisture barrier).

[Holm-Made]

Jason, you can bring it by the shop some weekend and I'll help you.  I do it all the time.  Chad

[Jason Jelinek]

Chad, thanks for the offer!

I made about 20 strokes on each face yesterday, drew it back about 20 times and it didn't seem like the draw weight dropped much at all.  I feel like it's going to take some time, but I'm in no rush.

[Jason Jelinek]

The limb thickness at the end of the fades was about 14.5 mm when I started, I now have them down to 13.75 mm, 9 mm down to 8.5 mm at the tips.  The bow started at about 64# and now its around 62#, it seems like it should be lower than that.  Is that what you guys have seen?

I'm using sandpaper by hand, it takes some time, but I usually do it when the kids are outside and I can face a breeze to keep the dust out of my face.

[Jason Jelinek]

I just did the conversion, it looks like I've taken off about 0.03" of glass.  So 2# of draw weight for .03" of glass, another .025 should get me the rest of the way according to Randy.

[TradBowyer]

i've never had a lot of success sanding glass to reduce weight. Plus taking that much material off, you have to be careful how you actually sand or you will get waves in the glass which really show up when you spray it. I bet you would lose the rest of the weight if you really round the corners of the limbs. Round them off real good on a belt sander and i bet you are there. Then again, listen to Chad, his work speaks for itself

TIM

[Chuck Hoopes]

Ive always had good success just taking it off the sides, thus narrowing the limbs.  Ive been shooting a Howatt Hunter for the last yr. that was reduced from 70# to 53# this way.  I have done likewise w deep core longbows with similar success.  Just need to go slow, and keep pulling that bow, and checking tiller.  Really, no big deal.  Ive got a 62


 Ive always had success by taking it off the sides.  Ive done this many times w/ deep core longbows, and recurves.  For the past year Ive been shooting a Howatt Hunter that I reduced from 70# to 53# this way.  No big deal.  Just go slow, and keep pulling to excercise those limbs as you go, and of course check the tiller.  Iam going to take 62# deep core longbow down to 55# in this manner, this week.  I actually start w/a belt sander to get them down some.