It's Guess the Recipe Outcome Time Again...

[Dick in Seattle]

I’m close to laying up the next bow.  I just have to complete my quilting project first and I’m hard at work on that.  I’m guessing maybe Monday or Tuesday will be layup day, using the new form.

I’d appreciate reactions to the “recipe” I’m considering.

Slowpoke was laid up at:  

.040 clear glass - .090 oak lam, parallel - .110 maple core, tapered .002 - .070 oak lam, parallel - .040 clear glass

Total glass:  .080       Total wood:  .270

AMO: 68"

Final draw was 28@25 ----- 33@28


I’m planning on the same basic pattern, but I want to come out about 5# heavier.   I wouldn’t mind also finishing up at a couple of inches shorter, but 68” would be OK, too.

 I have on hand two pieces of clear glass .043.   This will obviously incline to making things heavier, but possibly by too much, so I figure I need to reduce the wood stack.   I’m thinking maybe two lams of osage…  one .110 parallel and one .110 tapered .002.  (Note… my sled actually seems to taper more like .0015…  at least as processed on the old drum sander)   I’m also thinking a tip wedge on this one.    If  you guys think that might come out too light, I also have a .050 action boo lam on hand that I could work into the equation.

I also plan on narrowing the limbs more quickly, not carrying the width so far up. Between that and the osage instead of oak, I figure I should get more speed, though not looking for a barn burner.

So, what do you think?


I also have another question, re tips/nocks and the use of faster string.   Does a tip wedge serve to strengthen the tips in the same way that an overlay does, or are both required to be really safe in using FF string?  We’re conducting some comparative experiments with ff vs. B50 over on the Hill list and I’d like to try both on this bow when it’s done.

[Bradford]

From everything I have read up on in the last week, you should overlay for FF.  The other option I read.. which sounded good.. was to cover the FF with dental floss so It's not so abrasive.  I guess the FF is so firm, it will sand away your knocks.  But if you cover the loops with something, you can get away with a standard knock.
Just what I have learned in the last week.

[DCM]

I've only done two glass bows, but dozens of selfbows.  I simply used 1 lam of core (for looks) and another lam of .040 glass to build up the overlay, versus some other "stronger" material like micarta.  I have another glass bow (Bobby Lofton) w/ a single elm overlay.  On selfbows I don't use any overlay and with woods as soft as elm and hackberry I've never had a problem with string abrasion.  I use 12 to 15 FF usually.  

I think much more important is the shape of the string grooves, pronouned teardrop w/ lots of surface area, no sharp spots, and cut so the string lays straight at brace.

I think generally folks look for low SG material to make more effecient core lams.  Osage and oak would not rate as high as boo, lam boo, lam maple, red elm, etc., as I understand it.  No direct personal experience myself.

[adam]

I agree with what other people have posted. If using FF use tip overlays and serve your loops. If you don't want to serve your loops i've heard people using super glue finish on the tip so they are more durable.

As far as the lay up i would use the bamboo core and the osage for belly/back lams. From what i have read you want a light core wood and heavier veeners. I also agree with your idea or tapering the limbs more. you should pick up a few fps. As far as the lam thickness on the bows i build .003 difference usually give me +/- 5 lbs.

If you wanted a shorter but a tad heavier i would use the same layup as the bow before but make a 66" finsihed bow. That should give you the extra 5 lbs.

But i have only built a few laminated bows.

[Roy Steele]

One thing about LAM bows all you need is the right recipe.