Official Luthiers Forum!

I've got a set of Osage Orange that I started working on long ago, then put to the side. Back is joined, sides were thicknessed. I'm seeing cracks in the unbent sides which run perpendicular to the grain of the wood. I've not seen this before. There are about 20 cracks in one of the sides, none on the other. Any ideas as to what causes this? I think I'm going to need some new sides. Thanks

Sounds like the wood wasn't entirely dry.

Kevin Looker

_________________
I'm not a luthier.
I'm just a guy who builds guitars in his basement.
It's better than playing golf.

Perpendicular to the grain has me stumped. Parallel to the grain is what I would expect. If that was the case I would bend, clamp and flood with ca, but perpendicular? New sides for sure.

_________________
Joe Beaver
Maker of Sawdust

A picture would be helpful to understand what your seeing. Perpendicular cracks is very peculiar. I'd really like to see.

Ah, more reasons not to work with osage orange.

Have lots of OO,it/s troublesome to dry but well worth using IMHO. OO wood here in the midwest it/s prone to checking You might consider CA for cracks thinning the sides to .080 or less so they can be bent quickly without more splits/cracks and then using a backer veneer.022 on the inside for sides e.g. Walnut, mahog etc.

I have made quite a few OO guitars--most of them with wood from the same tree. I've never seen the problem you describe. I feel the resulting guitar is well worth the extra effort of working with Osage Orange.

You see this type of crack in wood when the tree experienced a major stress during the felling process. If a huge spruce tree is felled and it lands across a boulder or another tree trunk, then it sustains stress fractures.
As for your set: possibly the side that is showing the checks was on the outside of the tree and took the brunt of the felling force? Another possibility is the wood growing under some type of tension.
In any event it sounds pretty dicey to use it.

_________________
Stay with the happy people.
--Reynolds Large

Huh. Osage Orange is a phenomenal Tonewood. I have Osage Orange sets that ring louder and longer than Brazilian Rosewood sets in my pile. It generally works well if well processed. And it can make for a very distinct and unique looking guitar.

It's not entirely clear what is meant by "perpendicular to the grain." If you mean cracks at a 90° angle to the length of the sides, I agree that is a very odd configuration. If Osage Orange is not processed and dried correctly, all sorts of checking can and will occur, but I've not seen that. I'd be interested in seeing a photograph.

_________________
Aaron Craig

If it's curly, then cross grain cracks can form in the most endgrain exposed areas (they're actually radial cracks in that case), but if it's straight grained stuff, then that is strange. A picture would definitely help.

I agree with Bob and Aaron, osage is an excellent wood and just because you got a bad set is no reason to swear off the entire species. The set I'm currently working with (from Aaron) has been very cooperative. Not too tough to plane (a little stringy though), and bent easily with no cupping or ripples. And one unusual thing was that I didn't have to do any touch-up bending even after letting the sides sit for a week or two, with some fairly significant humidity fluctuation. Super stable.

never seen curly osage. sometimes odd flecking patterns but never curly. I agree with the previouse diag. sounds like what i call a wind check. osage is super tough and will with stand the super winds of a texas thunderstorm. afterwards the tree will heal it self, but not as good as before. the crack will fill with minerals ets. So ive been told. made lots of bows with osage and run in to wind checks from time to time. i'd say you need a new set.

Since the checks are only on one of the sides, I suspect it comes from seasoning checking on the surface of the original board.
Cross-grain cracks are more common on slab-cut wood that has runout.

_________________
John

sounds like maybe wind checking but the fact that it is only on one of the sides(are sides bookmached?) makes me wonder if it is checking that occurred in the planer years ago that was over looked, and is possibly worse /more visible do to temp/humidity fluctuations, over time.

For all that it's hard and tough, Osage can be surprisingly splitty on the surfaces. It's possible that in areas where there's some runout you've got surface checks. This would be exacerbated if the wood was not really smooth before it was bent. If the side in question was planed against the grain, either by hand or with a joiner/planer, and was not scraped or sanded down past the surface checks, they would come out later. That could explain why only one side showed the problem: you planed them both in the same direction, and on one side that was right, but not on the other, since they were book matched. Think about what you see on a top with runout as you cross the joint.

Try flooding them with thin CA, and see if they go all the way through. If so, make sure you've backed them up with something, either the liners, or a side tape at least. If they don't go through the dark mark of the CA will show you when you've scraped deeply enough to be rid of them.

DO scribe the sides before routing for the bindings!