Reducing draw weight

[Polifemo]

Hi,

I recently bought an old Bear Super Grizzly which turns out to be to heavy for me...

I don't hunt and 55# is more than I can comfortably shoot arrow after arrow with.

Having built a couple of selfbows (I've got some tools and hopefully also some skills) I'm thinking about trying to reduce the draw weight by reducing the width of the limbs the EXACT amount on both sides and on both limbs.


If possible I'd prefer the bow to be around 45# which is a reduction of about 20%
Do you think that this could be done?

Would anyone dare to estimate approximately how much I need to reduce the limb width in order to obtain this?

I will of course start by taking off a little at the time checking the tiller and weight of the bow in between.

[inksoup]

is it glass bow?
if so you can try to file some of glass back and belly and measure again... since the 80% power of glass bows are generated by the glass. but do not go too deep. otherwise you will ended up broken limbs...

otherwise the process is the same... just scrap some from back and belly and measure... until you reach to your aim...

best.

[Polifemo]

Yes, it's maple reinforced by glass.

Thinning out glass on back/belly seems difficult indeed...

I was hoping that narowing the limbs, which is quite easy to do and that probably will look good as well, should be the way to go.

Selling the bow, untouched, is of course alo an option.

[Roy from Pa]

I don't make glass bows but I have worked on a couple. I never liked the idea of sanding the back or belly of a glass bow. My buddy made me new limbs for my take down and they were about 10 pounds too heavy. So we kept sanding equal amounts off the sides to reduce the weight. We took an 1/8th inch off each side to drop 10 pounds. We used an edge sander and just counted the strokes we took off each side. Just kept doing that to get down to the weight I wanted. We did stay a little bit away from the last 6 inches of the tips though. Came out perfect.

[LittleBen]

FWIW higher weights like 55# seem to sell for higher prices on the auction site. Might put a few bucks in your pocket by selling and buying another in 40-45#

[macbow]

10# is a lot but doable.
It works better removing from the sides with longbows.
If you didn't pay too much you would be better getting your money back and rebuying.

Like Roy said it might take 1/8 inch. Sanding the back and face takes along time.

[PEARL DRUMS]

10# is a lot and when removing that wood/glass from the sides you'd best watch that tiller. It will and has to change.

[monterey]

The general rule of thumb is that reducing width to half will reduce draw weight by half. That would probably be a pretty good formula to carefully follow.  That would dictate reducing limb width by 20%.  Reducing the thickness of the limbs is a much more sensitive process and I agree that it could result in broken limbs.

I'd sell it and buy another.  Your weight reduction plan will probably hurt the bows value even though it may not deliver the result you desire.

[cunruhshoot]

As others have mentioned I would go with the plan to sell it and buy the weight you desire. If it was a longbow I might attempt reducing weight by narrowing the sides evenly and trapping the limbs (although 10 pounds is a big reduction). my understanding is that recurve limbs are more sensitive twisting due to the fact that by design the limbs are thinner and wider and can twist more easily.

I don't build recurves only longbows so someone else will have to verify if that limb info is accurate.

[LittleBen]

Heck if yu go over to the classifieds you might find someone to even swap with for. 45#.

There's always someone looking to go up in weight to hunt or whatnot.

[kennym]

10 # is a lot, I'd be afraid I'd end up with a limb twist. I'd go with selling or trading for a bow intended to be a lighter weight.

[Polifemo]

Yeah, selling it probably is "the right thing" to do.

I really wanted to be able to shoot this mid 70's Super Grizzly as I really love shooting the early 60's Ben Pearson bow that I bought at the same time.

I'll probably keep it for a while in order to find out how much my technique and strength develops (been into archery for a little over 3 months) but I seriously doubt that ever will be able to shoot 100+ arrow sessions with this bow...

[mikkekeswick]

A 20% reduction in weight would need a reduction in width of 20% - that bit is easy  
Doing it accurately is the hard bit  
You can also lose a few pounds by sanding the belly glass only. If you keep your passes even you should be ok. I use 240 grit then finish with 320.
One of my recurves ended up with the same problem as you have - 10# too heavy. I successfully dropped the weight by a combination of reducing width, rounding the edges over and sanding the belly glass. It didn't develop any twist and shoots fine.
It is 'doable' but my bow was the first off a new form. As such it was there to be messed about with and had no real value to me.