tri-lam question

[upstatenybowyer]

How critical is it to taper the middle lam? I mean, if your backing strip is super thin (and high quality) say 1/16" thick and your middle lam is 1/8" that still leaves a decent amount of wood to work with for the belly right?

[Bayou Ben]

That would work Jeff.  You would have enough belly meat to put in your taper. 

I’ve found though that on these bows the closer you are to final dimensions at glue the better it will come out.  And a mid lam taper gets you that much closer.  I like a taper on all 3; it helps them bend nicely at glue up too. 

But if that’s all you got to work with, your plan should be fine.

[Pat B]

I've never tapered lams for a tri-lam. After tillering the belly lam ends up tapered. I've only made a handful of tri-lams and they all turned out well. Tapering may help you achieve a specific profile like a R/D or recurves easier but they are not necessary.

[Del the cat]

That would work Jeff.  You would have enough belly meat to put in your taper. 

I’ve found though that on these bows the closer you are to final dimensions at glue the better it will come out.  And a mid lam taper gets you that much closer.  I like a taper on all 3; it helps them bend nicely at glue up too. 

But if that’s all you got to work with, your plan should be fine.

+1
Del

[silent sniper]

Jeff,
 I taper all of my laminations before gluing them up on a tri-lam. This ensures that you bow is going to be somewhat bending well when you take it off the form. I have found that with R/D profiles you will still have stiff spots mid limb off the form even with tapered lams. The more work you do in the building stage the less work you have to do after it is glued up.

I have shot some bows that were built by laminating multiple (4-6) 1/8" non-tapered lams together with epoxy and then tillered through the lams just like the growth rings of a selfbow. I have not tried this method yet, but the bows I shot were quite nice. It would make the process for building a multi-lam bow much less time consuming then having to taper each lam before glue up. Food for thought if nothing else....

Enjoy, SS

[upstatenybowyer]

Thank you all very much for your replies. I have a bit of a confession to make... I had already glued up a tri-lam w/ non-tapered lams when I posted this. 

I now completely understand why the tapered lam approach makes so much sense. I think this bow could definitely end up a success, but it took a ton of work to get her bending. I've got her at a low brace and still have enough belly wood to finish without cutting into the middle lam, but there'll be less belly wood then I would have liked.

Thanks again you guys.