Bamboo backing - small nick

[passion for knowledge]

Working on my latest tonight and I managed to touch the sander belt with the back of the bamboo backed ipe I have on the go at the moment. Just inside the fades. Not very deep or large - about 1/32 deep and a bit smaller than a dime.

How worried should I be?

I was thinking of putting a small amount of epoxy on it to prevent any possibility of splinters.

Any thoughts?

[Pat B]

Will you post a pic? If it were in the handle I wouldn't worry about it but if it is in or near the working portion of the limb it could be trouble. The strongest fibers in the boo are the outside fibers.

[Roy from Pa]

What Pat said.

[passion for knowledge]

Forgot to take the camera when I went up to the wood shop.

I think (hope) I'll be OK having looked at it a bit more closely.

It's an inch inside the fades and I have power lam an inch longer at each end of the fades. The ipe belly also fades out into the rest of the limb. Where the nick is doesn't look to be bending when I put it on the tillering tree.

Was hoping to get the short string on yesterday, but time got the better of me. It's #50 at what would be a very low brace. Should get the short string on next time. Won't be able to get at it until Thursday, though.

Eyes, legs and fingers crossed!

[Pat B]

What is your ultimate draw weight? If your bow is pulling 50#@6" now then you have 65# or so pounds to loose before you hit full draw. Get your bow to within 10# to 15# of it's ultimate draw weight before you go to low brace.
 The boo backing is in tension as the bow is drawn. The power fibers in boo are long strands that run from node to node. With the back being in tension these strands are pulling against the non working area and a break in those fibers can lift under tension.
 The power lam should help prevent that area from bending.  This kind of thing(nicks and scrapes) is why I don't use boo backings very much. I have been disappointed by them in the past. Boo backed bows are the Cadillac's natural material bows but they also have weaknesses if proper handling is not observed.

[Roy from Pa]

David, no way should you string up a bow that's 50 pounds at a low braace.. If you have a slight hinge somewhere, stringing it up will only magnify that hinge. And cause greater damage.

[passion for knowledge]

Pat, Roy.

Thanks for the input.

I'll lose some more material before I sting it up.

[Carson81]

I did this recently with my sander but at the tip end. I took my scraper and basically chased it down a "ring" so that my back was no a fairly uninterrupted layer of boo fibers.

Just to be clear, I wasnt straining my eyes under the lights to perfectly chase the layer of fibers down, I simply took a small area of fiber violations and spread it out over a much larger area. A well sharpened cabinet scraper is handy for making light of such work.

[passion for knowledge]

Got a couple of hours in on the bow today.

Unstrung, the tips are 2in in front of the middle of the riser portion.

Got it to #38 with tips 7in behind the middle of the riser. Bending nice and even.

Time for the short string yet??

[Pat B]

If everything is good then you can low brace now. Keep an eye on it in case something shows up under the stress of bracing.

[passion for knowledge]

I'm going to go real slow.

Scraper and sandpaper only and lots of visits to the tree!

Patience is a virtue, or so I've been told!

[passion for knowledge]

Well, this one got away from me.

Struggled with tiller all afternoon.

Got it on the short string.

Tips were bending a bit too much and mid limbs were kind of stiff. Tried to even things out but couldn't quite get there.

Once it got down to #40 after all my struggles, I decided to stop. It will shoot, but the tiller is not good.

I think I should have thinned the boo a bit more.

Not a total fail, but I'll know better next time.

Think I'll avoid 'boo for a while.

Had very little trouble tillering my previous two laminated bows. This one was a serious pain.

Wood combo looks nice, but I'd rather have a shooter than a looker!

[Pat B]

Hickory is very good backing, easy to deal with and you can tiller some from the back.
 What are the dimensions of this bow?

[passion for knowledge]

Funny you should say that, Pat.

When I got home, my first thought was that my next one will be based on my recent hickory-maple-ipe tri lam but using the form I used for this one.

My maple backed ipe and the tri lam hardly needed any serious work, other than slight adjustments for limb twist.

I guess bow making, especially all wood bows, is a journey with no end!

I'm not calling this a success, but at least it didn't break and it's about the weight my daughter shoots, when I can persuade her to come out with me.

I think I know, mostly, where I went wrong with this one. I'll call it a very good looking learning experience!

On to the next one!

Maybe I'll take another look at 'boo when I've got a few more under my belt.

Bow is 66" NTN

1.25" at the fades = 1/2" wide at the tips.

[mikkekeswick]

Put a wrap around that section. Boo can let go unexpectedly with even slight violations to the power fibers. Don't trust it.
yes make the next boo backing no more than 1/8th thick with the edges paper thin.

[Roy from Pa]

Make it lighter by fixing the tiller, then give it to a young kid to plant the traditional seed.