Quad lam - 4 laminations - Why not more?

[orangputihkgu]

Hello to you all! 

I have seen lots of Tri Lams. Why are there so little Quad Lams? 

According to EWBS description a non-historical bow may have up to 4 laminations but somehow this kind of bow is rather a rare species. I can only recall a pictutre of a 4 Laminate made by a member of the EWBS-NZ.

So why are there no more of this kind of warbow? To difficult to make? No real advantage having a fourth lamination? Any difference in performance compared to the Tri Lam?
Did anybody has hands on experience in shooting a Quad?

Any input and information appreciated!!!  :

-cheers.......CHRIS

[Thesquirrelslinger]

Aside from looks, what would be the benefit of an additional lam?
The back is tension, Belly is compression. The core is shear strength and stiffness.
Making the core 2 lams increases the likelyhood of a delam b/c the glue line is under extreme stress(it is right where the wood wants to shear)
Just my 2 cents, from a person who has never made a laminated bow...

[Newindian]

Maybe us bowyers are just lazy

[BowSlayer]

Aside from looks, what would be the benefit of an additional lam?
The back is tension, Belly is compression. The core is shear strength and stiffness.
Making the core 2 lams increases the likelyhood of a delam b/c the glue line is under extreme stress(it is right where the wood wants to shear)
Just my 2 cents, from a person who has never made a laminated bow...

+1

[adb]

Making a quad lam would be no harder than a tri lam. Just slightly more labour intensive. You'd have to make sure your lams weren't too thick, especially the core lams. I often make tri lams, because I can make more bows with less wood. I need less precious belly wood to make a bow. They also look very nice with contrasting woods.

Proper glue lines are not weak. If done correctly, they're stronger than the surrounding wood. I've never had a glue line failure on any bow, including heavy warbows. The wood itself always fails first. You'd also have to watch that your limb's physical weight didn't get too high using dense core layers. I don't believe there is any advantage to making a quad lam over a tri lam.

[Hrothgar]

I don't see any advantage to having additional lams. Howard Hill bows are routinely made with 4 lambs and sometimes up to 6, however.

[mikekeswick]

It is pretty much just for looks the way most people make them. However adding extra lams under perry reflex may have some benefits but you have to do 3 glue-ups.
Why on earth would a 4 lam bow by more likely to fail at a glueline??? If you prepare shoddy surfaces and then expect the glue to hold it all together fair enough but if they are well prepared and you follow the way the glue should be used - no problem.
I quite often make quad and more lam longbows. It just starts getting tricky to 'fit them all in'. The best way to do multiple core lams is to taper them all......which can be a pain but does look pretty special!

[toomanyknots]

I have been making some reflex deflex bows lately with a good about of bend in the glue ups. I notice when comparing a glue of just a backing to a belly, it will not hold it's reflex too much right out of the form. I mean as soon as I take the bow out of the from the limbs come down a bit loose some reflex. When doing basically the same bow but with 2 belly lams instead of one, it holds it's reflex a lot better right out of the form, and doesn't seem to loose any at all. So might these observations of mine be indicative of added stability/stiffness?

[mikekeswick]

No it's just that it takes less force to bend thin lams to the shape of a form than it does a thicker belly lam and a backing. Equal and opposite reaction and all that.
If you don't thin your belly lam when doing a perry reflex glue-up as you remove bellywood the reflex increases....now that's a fun situation.

[Dances with squirrels]

It sure does. Mike, you are one of the few I've heard recognize the 'reflex gaining' phenomenon. It can be quite the adventure. The more wood you remove, the more reflex it gains, making the limb appear 'stronger' than the other on the tree, so you scrape off even more.... etc. It hasn't happened to me since I began carefully pretapering my pieces and got a bettet feel for how much material I needed to be closer to final thickness after glue-up.

[warpath]

Many years ago I had a bunch of yew that was already cut into thin 1/16" sheets for glass bow laminations. So.... I decided to make a bow with a ridiculous amount of laminations just to see what would happen. It has 8 laminations of yew, (not including the handle riser). Then a back and belly lamination of the evil glass stuff. At an overall length of 68", 66"NTN, it pulls 110# @ 30". She's a real sweet shooter and flings an arrow like a rocket down range. I still have her.

  G

[adb]

I'm sure it's an awesome bow, but once you add FG to the lams, everything goes out the window. The core lams (regardless of how many) just become a platform for the FG. The tiller and draw weight are only determined by limb profile and thickness.

[mullet]

I'm sure it's an awesome bow, but once you add FG to the lams, everything goes out the window. The core lams (regardless of how many) just become a platform for the FG. The tiller and draw weight are only determined by limb profile and thickness.

I have to agree, once you add the glass, the rest is for " looks". You could get by with one or two Lam's for a functional glass bow.

[bow101]

You just end up with the possibility of more glue line failures. More wood to glue.  My first bow was 5 lams, because I thought it would be better.  Wrong, a tri lam would of been sufficient.  The other reson was I had a dozen or so lams cut at a very thin margin.  The next bow I'll try a mild R/D  having 2 lams. Either 2 maple or Oak & Maple. Backed or unbacked....

[Newindian]

When you glue up lots of laminations would the glue start to add excess mass?