As a general rule, how much do you guys increase stack thickness when building a 2" longer bow on the same form as a shorter bow? I'm not changing the length of my riser, just increasing limb length.

.015 on T/D recurves

Just longer tip or backing the wedge up ??

It's a one piece hybrid. I've been building 54" bows off this form for 6 years. I recently built a 56" bow off this form but was short on weight. I can go as long as 58" on this form but looking for suggestions on how much to bump op my stack.

I generally get 4-6# more if I shorten 2" and 4-6# less if I lengthen 2".  So I would calculate the desired lam thickness using the lam stack calculator and your known lam stacks from your historical bows using that differential

Thanks for the info.

5-7 lbs. for two in.

I have built several 54" bows that come in around 49-50 pounds with a .310-.311 stack. Anyone care to take a stab at the stack I should go with for a 58" bow at 42-43 pounds?

JGR, I need to edit my previous comment on 7# for a 2" change - my notes indicate 4-6# instead - sorry about that...thought I had that memorized!

I plugged in your data to the lam stack calculator.  With a .311 stack your 54", 50# bow would produce a 40# bow at 58".  To get a 43# bow at 58" - I think you should use a .319 lam stack.

Mileage will vary of course - you know how it is. If you need a copy of that lam stack calculator, send me your email in a PM - or you maybe able to find an old link on this site.

Thanks Brad. I came up with about the same number with the stack calculator as well. I was hoping to get confirmation that It was correct.

JGR .295.
And its gonna depend on what the weight range of the bow is lighter bows be less than heavier bows

Glued up yesterday and roughed in this morning. I went with a .300 stack at the butts, 58", with 7 5/8" brace and it's 46#@27". She's 1 1/2" at the fade outs and 5/8" at the tips so by the time I take the limbs down to my usual width and work the tips I should be about right.