Lam number question.

[mwosborn]

Would there be much difference in performance using a single parallel lamination twice the thickness of 2 separate laminations?

For example in these two stacks.

2 - .04" glass
1 - .120" taper .003
2 - .06" parallel

2 - .04" glass
1 - .120" taper .003
1 = .120" parallel

[kennym]

I've never tested this theory but I think more lams will be stronger just like hi grade plywood. So maybe a couple lbs extra with same stack.

[mwosborn]

Thanks Kenny.

2x Kenny...   I don't have personal experience with that but what Kenny says makes sense and an old experienced bowyer told me the more lams the better...

[Al Dean]

If the 2 lams were from the same piece of wood cut one right after the other vs one lam from same piece of wood I doubt there wood be any difference.  There is basically no way to prove a or b since the wood is gone. There are several bowyers that use the 2 lam style.  Bama bows for one.

Al...   Here is something for you to ponder...  Get a 2x4 and rip 4- 1/4" thick pieces and 8- 1/8" pieces... Take the 1/4" pieces and glue them up in a 24" dia. half circle... Do the same with the 1/8" pieces...  Now see which one has less spring-back...
   In a bow it may or may not make that much a difference... It depends on the bow, the radius of the limbs, length of the limbs, thickness of the limbs and how thick the lams will have to be...  On a lightweight bow you could get by with 2 core lams... With a thicker limb bow more lams would be a wiser choice...  However on a straight limbed 70# Hill style bow you could get by with one core lam... But its be proven that a laminated wood with  the grains somewhat crossing will be consistently stronger than a solid piece of wood...

[Robertfishes]

On a one piece bow with typical riser design... you will have to use the two 060 laminations because it would be very hard to get a .120  lamination to run up the typical riser fade without a gap between the riser fade and lamination.. even with 60 psi in the air hose. I prefer those lams to be 070 or less.

[Al Dean]

I don't disagree with more lams, but are we saying a self bow, basically one lam, is junk?

[Crooked Stic]

More lams less spring back = stiffer and a bit more power stroke. Enuff to worry about ? every little bit helps.   :D

[Bvas]

Originally posted by Al Dean:
I don't disagree with more lams, but are we saying a self bow, basically one lam, is junk?

I don't think anyone is saying they are junk. Merely that a single piece is going to be weaker and more prone to failure.

2x Crooked...

Originally posted by Robertfishes:
On a one piece bow with typical riser design... you will have to use the two 060 laminations because it would be very hard to get a .120  lamination to run up the typical riser fade without a gap between the riser fade and lamination.. even with 60 psi in the air hose. I prefer those lams to be 070 or less.

That is a very good point Robert...  But there is a trick to that...  Unless your ramp design absolutely aesthetically calls for that curve, if you flatten out the last 3/4" of the ramp I'll bet you those thicker lams will lay down nicely...  Provided you do not have an extreme curve , of course...

[kennym]

Originally posted by Al Dean:
I don't disagree with more lams, but are we saying a self bow, basically one lam, is junk?

This is just a curiosity question for selfbow guys: more growth rings or bigger ones for better performance ?

I don't know much about them, maybe someday when things slow down a bit.....

[Crooked Stic]

Reply With Quote
I don't disagree with more lams, but are we saying a self bow, basically one lam, is junk?
I dont even think you are comparing apples to apples
. They are both bows. One with modern composites one with natural wood crafted to bend with good tiller.
Not junk if done right.

[kennym]

My thought question was if a selfie has tighter rings, is it a better performer(usually)?

 Wouldn't this be like more laminations except no glass?

[Al Dean]

Good point on the rings Kenny.  In essence a self bow properly made is some what similar to a lam bow.

[kennym]

Without experience I would think tighter rings would be stronger, therefore stiffer with less thickness? Just thinkin out loud....

[Bvas]

Or does the ratio of light to dark wood (early/late rings)have an effect on performance?   :confused:

I was just trying to research that with Douglas fir...  Do any of you guys have experience with DF??  Would you want smaller tighter rings or have them spread out..??