pics of power lams in the stack??

[arrowlauncherdj]

Can anyone please post some pics of power lams in the stack.  I am trying to modify a recurve design and want to push the bend a bit off the fades.  I have already made the new prototype, but I wanted to see what others have come up with and what it looks like glued up.

Thanks,

Dave

[JamesV]

Dave.............

 I only build longbows so this might not apply. I have never used a power lam what I do is, if I want the limb to bend farther from the fade I stop my taper maybe like 2"  from the fade, allowing the bend to be more mid limb or closer to the limb tip. Also your taper rate will have a big effect on where the limb bends

[Robertfishes]

this is the only pic I have, one bullet is pointing at the end of the riser fade, the other bullet is pointing at the end of the "power lam".. I don't have a drum sander to taper full legnth so I just use a .030 or .040 actionboo parallel and carefully taper last 2 inches of each end with a sanding block, I usually make them 3 to 4 inches past each fade. location in stack is belly glass, veneer, taper, powerlam, riser, back veneer and back glass..  

[kennym]

Like Robert, I usually go 3-4" past the tip of riser, and use about .010 per inch p-lam that is parallel from 3" or so in from riser tip toward bow center.

[Robertfishes]

I am still experimenting with the PL's. I think Kenny may use a sled and drum sander to presision grind his. It takes me at least 15 minutes to hand sand mine, I use a digital caliper to measure thicknesses as I sand..and reading glasses of course

[rmorris]

Does anyone use fiber glass as a powerlam?

[Dmaxshawn]

I have used glass as a power lam kinda sort of but it was when a bow missed weight drastically.  So I used a 18 inch piece of 040 with a .006 taper and set up the bow again in the form and glued another piece on the belly.   It acts as a power lam but its on the outside instead of the inside of the stack.  the glass was not as clear as usual but it came out great and the guy couldnt even tell it was on there after I put on 4-5 coats of epoxy finish.  It added 8 pounds after I got it all resanded.  Brought it up from 39 to 47 lbs.

There a few of the big timers that when you look closely at there pics of their bows you can see glass PLams in the stack.

[kennym]

I used some glass on a walnut core, black glass bow. Like Shawn, I did it after the fact. Hard to get the black blended in, now it is my camo painted limb huntin bow......

[arrowlauncherdj]

I hope I am going to be ok with what I did.  I took a piece of cherry lam .04 thickness and put it in the middle of my stack of 3 maple lams.  I let it go out about 3" past the fade at full thickness then tapered it the last 1.5" to feathered edge.  I am using a .002 taper in the limb.

Here are 2 pics before the PL. At brace it looks a little compressed with the 8* pad angle:

 

 

On the next one I was going to go another degree on the pad angle up to 9* and with the PL, I am hoping for a  bit less work at the fades.  The bow above had pretty good performance and shooting characteristics, but I figure a little less mass moving forward cant hurt.  I dont have a thickness sander, just an oscillating drum, so I made mine with a sanding block as well.

[Robertfishes]

I think you will have about 4 lbs more of draw weight using that P L, maybe more??

[arrowlauncherdj]

That's ok Robert.  I went down on the stack from .260 to .250 to accommodate that difference.  I did not include the PL in the stack calculation, just the base lams and glass = .250.  The bow above was for Trux in another swap and I had to really round the edges and do a bit of sanding to get it down to 54@28.  

I am gunning for 50 +/- 2lbs. on this one.

[Buemaker]

The issue of powerlams comes up quite often.Some say they want to push the bend a bit further out from the fades or stiffen that section a bit. On an all wood laminate bow with a glued on handle on the belly side so that section does not pop off I see the benefit. A lot of glass laminated bows have been made and is being made without a PL. So is it really necesary or could the handle section including fades just be made longer if you want a shorter working limb? That is for a glass laminate. Bue--.

[kennym]

The handle section could be made longer , but you get stiffer material when lammed. Also the cost of riser wood is saved by using a p-lam on a one pc at least.

On a TD, you can also use a p-lam tho to manipulate where it bends.


I can pick up a couple fps by using a p-lam and tip wedge in my d/r.

The way I see it, it bends the limb in the center section more, and acts as a catapult when fired, making the tips move forward faster??