Why did it break?

[matts2]

I finished this bow over a week ago and shot it a ton.  Even had a buddy shooting it a bunch in the shop.  I put it up and it sat for a few days and I grabbed it to take to league last night and figured I would take a few practice shots before I left last night.  Never even got an arrow in it yet.  First pull and snap.  Its a oak board bow with a hedge belly lam.  This thing shot great and I was really looking forward to shooting it.  Oh well, I guess I will have to make something else.

What could I have done to prevent this from happening or was it just time?  Would a backing of some kind prevented this?

 

[PEARL DRUMS]

How thick was each lam? Osage is way more powerful in compression than oak is in tension. Could have been your problem? Since the osage is failry intact and the oak is exploded, my guess is over powering took its toll.

[Art B]

What Pearl said! Gotta ask, do you monitor the MC of your bows? What was the R/H where you keep your bow? Since your bow was performing great and then broke after several days of storage I would also suspect low MC........Art

[matts2]

Not sure what you are referring to Art.  Based on that, I doubt it.  It was in shop where there is no temp control when I am not in there.

[Roy from Pa]

MC = moisture content.
R/H could be relative humidity:)

But who knows what that Ole Fart got up his sleeve:)

[matts2]

oh ok.  The oak was a Menards board and I never did check the MC on it.  I assumed it was dry enough.  I forgot to check the hedge as well.  I have a moisture meter, but didn't use it.  As far as the humidity in the shop, I try to keep it between 0 and 100 and that changes regularly.  The oak being a bit wet and drying out makes sense.  I have a dedicated forced air furnace in my shop that is only on when I am in there.  It has one vent that blasts out high on the wall straight across the ceiling.  That just happens to be where this bow was stored.

[Roy from Pa]

I have electric heat in my bow shop, when not out there I keep it at 50 degrees. But being electric heat, I keep a humidifier running all the time.

[vanillabear?]

[matts2]

I don't have any pics of it at full draw or even from checking tiller.  I will have to take a close look at it tonight and really see where it broke.

[Pat B]

Just looking at the one pic you posted I'd say the tension failuse was along a grain runoff, not along the edge but across the back; grain feathering. Red oak isn't a good bow backing IMO and especially not a board. Hickory or maybe even maple or elm would have neen a better choice bor the back.

[matts2]

This bow was originally supposed to be a plane board bow and got over tillered.  I took to much off and it got to lite.  So the hedge was added to increase draw weight.

[Art B]

Matt, get you a couple temp/humidity monitors at Wal-mart or hardware stores for monitoring the MC of your wood/bows. Sure proof method that won't fail you like a moisture meter. I paid something like 6-7 bucks for my monitors. I keep one in the house where I store my bows and one for the shop. Use a humidifier for winter and airconditioner for summer time control.....Art

[Roy from Pa]

Use a humidifier for winter and airconditioner for summer time control.

Well now hain't you just Mr. Traditional Bowyer? LOL, is that how the Injuns did it Artie Boy?

[Roy from Pa]

Matt, what is this dark line down the side of the bow? Is that some sort of imperfection in the wood? Looks like it to me. Maybe that is what caused the failure..

 

[matts2]

That is part of the grain.  During finishing, I applied a dark stain after letting it sit for a couple minutes, I took thinner and wiped it all off.  That brings out a lot of grain detail.

[matts2]

Here are a couple pics of that line.  The first is prior to stain and that line doesn't show up a whole lot.  The one after is after finish and the line is now dark.

 

 

[Art B]

Originally posted by matts2:
That is part of the grain.  During finishing, I applied a dark stain after letting it sit for a couple minutes, I took thinner and wiped it all off.  That brings out a lot of grain detail.

Yeah Roy Boy, the rest of us knew that! Geez!!!

[Art B]

Hey, you got some skills bud! Ole Roy could learn something from you. Broke or not, I like it! Art

[Pat B]

Can we see a pic of the back at the break? What does the grain look like there?

[Shaun]

The reason it broke is that oak is a marginal bow wood. Why fool around with it except to learn how on an inexpensive material? The bow appears to be well made with considerable skill and artistic ability. Osage, bamboo, yew, hickory, ironwood, ipe, or other good bow woods - you'd still be shooting.

Another observation is that bamboo backing or osage belly can overstress the opposing wood - especially if that other wood is marginal in quality or grain orientation.

Looking forward to your next bow post - nice work on this one. Keep em coming.