Primitive Archer

Main Discussion Area => English Warbow => Topic started by: Prarie Bowyer on March 13, 2013, 12:39:41 am

Title: Lets talk tri-lams.
Post by: Prarie Bowyer on March 13, 2013, 12:39:41 am
Grrrr...

I can't seem to to get to dimensiton that resemble a long bow in three layers with out the built up grip area. 

What the heck is it with me?  I'm getting closer. 

What I'm aiming for is a simple bamboo backed "sumptin (purple hear, bamboo, yellow heart, Ipe... ) with a hickory or Ipe belly.  No extra clump glued on for the handle.  Unstrung should look like a stick.

I'm getting closer but how the heck are those other guys getting there.  I feel like I get so much extra strength from my glue lines that I build a club.


So if anyone is willing to share dimentions and thicknesses of laminations that would be lovely.
Title: Re: Lets talk tri-lams.
Post by: mikekeswick on March 14, 2013, 04:38:24 am
Backing upto 1/4 thick, core upto 1/8th, belly thick enough to make the total thickness upto 3/4 - 7/8th at the handle.
Gluelines DO NOT add stiffness, if we are talking about a standard glue-up then thickness determines overall stiffness. Remember to double a bows draw weight you only have to increase the thickness by an 1/8th.
Title: Re: Lets talk tri-lams.
Post by: Prarie Bowyer on March 17, 2013, 06:48:21 pm
What about gluing in reflex?
Title: Re: Lets talk tri-lams.
Post by: mikekeswick on March 19, 2013, 05:38:23 am
What about it?
Title: Re: Lets talk tri-lams.
Post by: Prarie Bowyer on March 19, 2013, 02:15:03 pm
Thoughts?
Title: Re: Lets talk tri-lams.
Post by: Ian. on March 19, 2013, 03:28:49 pm
I feel like there is a question missing, was it - how much weight would be gained by re-flex?
Title: Re: Lets talk tri-lams.
Post by: Yeomanbowman on March 19, 2013, 06:58:08 pm
Thoughts?
Too much reflex on a bow of this sort will lose weight as the wood will give up if overdone.  It also really effects stability in an ipe belly bow as it often wants to cast off to the side.  With a heavy laminated longbow, I have found a little reflex goes a long way. Say 1" or so. 
I made a 4 growth ring ash/mass160lb longbow with a straight glue up and it didn't follow the string over much.
Title: Re: Lets talk tri-lams.
Post by: adb on March 19, 2013, 11:36:02 pm
I've also found heavy draw weight bows to be rather unstable with even a little bit of reflex. I had to abandon an ipe bellied tri-lam cuz I added a bit of reflex, and I couldn't brace it early on without it rolling over. Shame, it was looking like a decent bow. From now on, no reflex on warbows for me.
Title: Re: Lets talk tri-lams.
Post by: mikekeswick on March 21, 2013, 05:15:32 am
The other guys have covered it!
I have many,many thoughts about reflex....
Specificity is a great thing when it comes to asking questions  ;)
Title: Re: Lets talk tri-lams.
Post by: toomanyknots on March 21, 2013, 09:42:40 am
I've also found heavy draw weight bows to be rather unstable with even a little bit of reflex. I had to abandon an ipe bellied tri-lam cuz I added a bit of reflex, and I couldn't brace it early on without it rolling over. Shame, it was looking like a decent bow. From now on, no reflex on warbows for me.

Were you trying to brace it at a low brace? I find any narrow profiled reflexed bow can be ustable, regardless of draw weight. You gotta give it a high enough brace to be stable from the start. It probably is more unstable the higher the draw weight though. The way I tiller a bow like this, is to use a mirror, step on the tillering string, and pull up. That way you can hold the bow stable when drawing it, until you get it to a high enough brace height to be stable and it wants to calm down and be a bow.
Title: Re: Lets talk tri-lams.
Post by: Prarie Bowyer on March 22, 2013, 02:36:50 pm
The other guys have covered it!
I have many,many thoughts about reflex....
Specificity is a great thing when it comes to asking questions  ;)

What if there is information that i could use and don't ask THAT question.  Basically I was getting at is it necessary?

I finished the bow up with about 2.5" of deflex... glued it up flat.  Next one I'll thicken the core... thin the belly at the center  and glue in about 2" of reflex if using Hickory sap wood. 

Ipe dosen't need it I know.
Title: Re: Lets talk tri-lams.
Post by: bow101 on April 07, 2013, 10:49:44 pm
I've also found heavy draw weight bows to be rather unstable with even a little bit of reflex. I had to abandon an ipe bellied tri-lam cuz I added a bit of reflex, and I couldn't brace it early on without it rolling over. Shame, it was looking like a decent bow. From now on, no reflex on warbows for me.

Thats strange you mentioned "Roll over" adb.  I always wondered 'bout it but never did ask anyone on here... ;D  Have you ever had a standard type bow roll over on you..? ???
Title: Re: Lets talk tri-lams.
Post by: adb on April 08, 2013, 02:05:31 pm
Nope.
Title: Re: Lets talk tri-lams.
Post by: Thesquirrelslinger on April 12, 2013, 03:23:08 pm
I've also found heavy draw weight bows to be rather unstable with even a little bit of reflex. I had to abandon an ipe bellied tri-lam cuz I added a bit of reflex, and I couldn't brace it early on without it rolling over. Shame, it was looking like a decent bow. From now on, no reflex on warbows for me.

Thats strange you mentioned "Roll over" adb.  I always wondered 'bout it but never did ask anyone on here... ;D  Have you ever had a standard type bow roll over on you..? ???
I frequently roll over the bamboo recurves I make, they are for little kids, they pull around 15-20 pounds, are bamboo, 2 layers.
If I make the limbs too narrow and the recurve too severe, I generally end up with a twisted piece of crud.
If I make the limbs wide enough, they shoot good.
Title: Re: Lets talk tri-lams.
Post by: AndiE on April 15, 2013, 02:02:07 am
Hi

What would be the best combination for a trilam?
I think hick-osage-osage!
What Do you guys think?

Greetings
AndiE
Title: Re: Lets talk tri-lams.
Post by: adb on April 15, 2013, 09:49:53 am
Depends on what you're trying to achieve. I don't think there's a 'best' combo for a tri-lam, but there are many very good combos.
Hick/osage/osage would be a tri-lam, but not a good one IMHO. One of the nice things about a tri-lam is the contrast in the colors of the different types of wood, and the combo you suggest would simply look like a bi-laminate bow. If you had two thinner pieces of osage you wanted to use up, this would be a good option, but there are much better options for a nice tri-lam longbow.
Title: Re: Lets talk tri-lams.
Post by: bow101 on April 19, 2013, 06:48:51 pm
Maple and white oak lams are good. Maple for back & belly oak core.  Never built a warbow. Thickness. I don't know try about .600 thou"            ???  It may get you about 80#
Title: Re: Lets talk tri-lams.
Post by: adb on April 19, 2013, 10:11:39 pm
.6 thousands of an inch??? I make my lams usually 1/4".
Title: Re: Lets talk tri-lams.
Post by: bow101 on April 19, 2013, 11:16:33 pm
Yes you are correct.  Getting confused on these fractions.  Really meant to say inch "  not Thou. :)

Bingham Projects chart.
eg. 68" longbow , 50# , .389"

 Bingham project charts correspond to their kits.
*all variables taken into consideration, riser lenght, wood used, etc.....etc....
Title: Re: Lets talk tri-lams.
Post by: adb on April 20, 2013, 12:30:19 pm
0.6" would be too thick. Like I mentioned, I usually make my lams 0.25". 0.6" would be about right for the belly wood however.
Title: Re: Lets talk tri-lams.
Post by: bow101 on April 20, 2013, 02:54:40 pm
0.6" would be too thick. Like I mentioned, I usually make my lams 0.25". 0.6" would be about right for the belly wood however.

Ya lost me, I meant total stack ...like in total thickness of a Tri Lam, 4 lams 5 lams whatever.

Bingham Projects chart.
eg. 68" longbow , 50# , .389"

Title: Re: Lets talk tri-lams.
Post by: adb on April 20, 2013, 08:07:48 pm
Isn't Bingham all about FG bows and laminations using FG??
0.389" is about 3/8" and that won't make a 68" 50# wooden bow.
Title: Re: Lets talk tri-lams.
Post by: bow101 on April 20, 2013, 11:33:39 pm
0.389" is about 3/8" and that won't make a 68" 50# wooden bow.

Mmm so how much..?
Title: Re: Lets talk tri-lams.
Post by: adb on April 21, 2013, 03:07:46 am
That's a very difficult question to answer. There is no secret formula in bow making with wood.

For a FG bow, you make it a specified thickness, shape, and width, and you get a predictable result. Not so with wooden bows. Depends on the wood, depends on the design, depends on what you want as a final result. I can't offer you a secret formula, or a specific thickness... they don't exist.

I think if I had three different bows, all with similar designs, and perhaps even with the same wood (or wood combinations), that they would all end up with different thickness dimensions. Wood is a natural material, and even wood of the same species will have variable densities. For me, that's part of the joy... not knowing... not being able to predict the final outcome with exact certainty.

You could probably end up close to 50# using hickory backed ipe and making it a pyramid bow with wide flat limbs, but it would be a gamble at 3/8" total thickness. I would definitely start thicker and tiller to desired effect.
Title: Re: Lets talk tri-lams.
Post by: bow101 on April 23, 2013, 05:10:07 pm
Sounds good, I think that pretty well wraps it up.  I'll try to keep it on the heavy side over  3/8" total thickness for sure.
Title: Re: Lets talk tri-lams.
Post by: Squirrelslayer on April 28, 2013, 07:42:32 am
The ELB im making will be a bamboo back, osage core, lemonwood belly. im doing it on a longbow making course on the 17th of may should be fun. SS
Title: Re: Lets talk tri-lams.
Post by: Cameroo on April 28, 2013, 10:57:45 am
I think you'd do better to have the osage on the belly, but that's just me.

When are you going to post a bow for us Squirrelly?  You sure talk about making them lots ;)   :P
Title: Re: Lets talk tri-lams.
Post by: Squirrelslayer on April 28, 2013, 04:14:46 pm
Well im doing the bow makin course on the 17th so I guesse some time around then.  Im also waiting for my maple to dry and ive got 14 exams coming up these next 2 months. But after that when its the summer ill be a bow makin machine! SS
Title: Re: Lets talk tri-lams.
Post by: WillS on April 28, 2013, 05:29:37 pm
Who's running the bow making course?  Bickerstaffe? Stratton?
Title: Re: Lets talk tri-lams.
Post by: Squirrelslayer on April 28, 2013, 07:21:24 pm
Its run by a guy called will lord. SS