A question.

[Buemaker]

I am going to help a friend make his first glass bow. We are going to use my form for a Hill style bow with one inch backset. He have bought Bowtuff clear glass, but only .030 inch thickness instead of .040. I have notes for stack thickness when using .040, but have never used the .030 thickness. Do you have any idea how using two strips of .030 instead of .040 will affect poundage? I guess one option would be to use his .030 on the back and take one of mine .050 on the belly. Do you think that would even things out. Thanks Bue.

[Arlo]

You are typically looking at .02 Glass = 2 pounds , so you are talking about 10 pounds difference using the same stack height on a 40-45# bow going from .040 to .030. Glass. I wouldn't use .030 on anything heavier than 45#.

If you wanted to mix it up using .050/.030 i'd use the .030 on the belly myself.  Arlo

[Flem]

Might be tough if you want to keep that backset. I think the .03/.05 combo sound sounds like a good plan.

[mmattockx]

If you wanted to mix it up using .050/.030 i'd use the .030 on the belly myself.

That's backwards, you want the heavier lam on the belly.


Mark

[Crooked Stic]

X2 .050 on the belly. There was a time when I got a bunch of .050 glass cheap. And used it instead of .040.  Can't remember it changing the weight that much as long as the stack was the same.

[Stagmitis]

Bue, why not put the .30 on the back and run the .50 through the sander and get it down to .40? I have settled on a .10 difference between back and belly on my Hills.  I wouldnt go over 50 lbs with this combo though.

[Pat B]

Good thing they cleared this up for you, Bue.     

[Flem]

You could just use the .03/.03 combo and add more wood the the stack to compensate for the missing composite.
Hill style bow's are thicker, with more working core anyways, so the lack of glass is not as noticeable as it would be with a Recurve or R/D bow.

[Arlo]

If you wanted to mix it up using .050/.030 i'd use the .030 on the belly myself.

That's backwards, you want the heavier lam on the belly.


Mark

There are a lot of backwards bowyers out there brother...

The reason i would go with .50 on the back of a Hill style bow vs .030 is mostly durability. . .030 glass wont take as much abuse as thicker glass, and hill style bows are more effective as clubs than bows anyway.....

 I honestly don't think its going to change the tension / compression dynamics at all either way on a deep core narrow limb...... Now if we were talking RC limbs that's a different story.

Arlo

[mmattockx]

The reason i would go with .50 on the back of a Hill style bow vs .030 is mostly durability. . .030 glass wont take as much abuse as thicker glass, and hill style bows are more effective as clubs than bows anyway.....

Clubs are useful sometimes! 

The reason to put the thicker lam on the belly is that compression failures occur before tension failures and the thicker glass lowers the stresses on the compression side. It will also reduce set if the design wants to overstress the core material.


Mark

[Flem]

If you wanted to mix it up using .050/.030 i'd use the .030 on the belly myself.

That's backwards, you want the heavier lam on the belly.

The reason i would go with .50 on the back of a Hill style bow vs .030 is mostly durability. . .030 glass wont take as much abuse as thicker glass, and hill style bows are more effective as clubs than bows anyway.....

Yeah, Howard Hill was not a very effective hunter. Neither was Bob Swineheart, or John Schulz, or .........

They might not be efficient, but effectiveness is unquestionable.

[Longcruise]

X2 (or X3 or X4, I've lost track) on the .05 on the belly.  😀