Adding colour strip help needed?

[wcdurand]

Hi guys. Just want to test my thinking if you could help me. --- If I want to add a unidirectional coloured fiberglass strip in the middle of my stack and if my stack was normally.310 thick would the addition of the fiberglass strip neccessitate me to lower the stack thickness because of the stiffer fiberglass core say to about .300 to have the same poundage, Or would the fiberglass being in the middle of stack not have such a big effect on the poundage. My thinking is that the stiffer fiberglass would up the pounds, but by how much?

[Krasus]

I just did the same thing on my last bow.  The .030 core tuff adds 10 lbs to the draw.  

[Bowjunkie]

A .030" piece of CoreTuff added to the middle will add about 10 pounds to the average longbow. Of course this is a ballpark figure as there are other factors involved.

Put the same piece into a thin, wide limbed recurve and the percentage of increase goes up, and it can add as much as 25 pounds.

I once made an 84# recurve because of this 'phenomenon' :^)

[wcdurand]

Really apreciate! I will take the stack down by. 015 then. Bow lenght is 58". Will post the results when finished.

[fujimo]

would that not add a lot of unnecessary weight to the limbs? slowing them down, and possibly making them more 'shockey'-?

[wcdurand]

Yes it might do so Wayne, it is .030 and the middle lam. My thinking is that if it is the middle lam the effect would not be so pronounced. I must say it is a lot of extra work because the two bamboo laminations must be grinded thinner and there is an extra glue line, which must also be kept in mind as it will add to the stack. The red line together with the accents in the handle should look very nice though. 7 lams altogether with the clear glass

[Bowjunkie]

Wayne, you would think so, a little bit anyway. I've done it with glass, with carbon, and of course with nothing but wood in there, and never noticed a difference between them... but then I don't have a chronograph so...

It's not a lot of extra work. Just takes a minute to slather up another lam.

I did it for a long time, but haven't put anything in the middle but wood for years.

[fujimo]

cool, thanks guys- just wondering about the theory. but i guess sometimes i chase this downward spiral of ever decreasing significance- when i should just really concentrate on building bows   :D  
good to know- thanks guys
as an old scots friend of mine always says "everrry daay izza skoool daay"      

i think it would really look cool though!

[Sixby]

It has more benefits than just looks. It establishes the neutral plane and keeps excess stress away from outer laminations, Sort of like leveling everything out. It also theoreticaly makes a limb tougher and last longer . That's why it is called core tough. It definitely increases horizontal stiffness and decreases limb torque.

All in all you have to weigh the benefits against the drawback of increased weight. I use it in most of my longbow models and have had nothing but compliments on the bows.

God bless, Steve

[wcdurand]

Thank you Sixby. I plan to cut this bow in half and do Big Jims take down system, so it might strenghen the takedown areas under the fiberglass and the tenan(male part) as well.