What Is This In My Wood?

[j. pierce]

(the top one is a little fuzzy from the cloth I wet the wood from)

Building a couple of necks out of padauk. On the original plank, it appeared to be a couple of nicks from being run through the planer, I didn't give it much thought. tapered the neck, and didn't really see anything on the sides, and progressed as normal.

Anyway, as you see in the pictures, these little black lines, they almost look like "wrinkles", continue through the wood for some depth as I carved away the neck. At no point do my blades get caught on them, at no point does it feel like an actual crack, I can't snag my fingernail or a pin or anything on it. It doesn't seem to be different than the surrounding wood in any other fashion than it's appearance.

So is this just some mineral inclusion, or some sort of defect? Will this compromise my neck at all?

[Myka Guitars]

I have seen these before in black limba. This and the Padauk trees are both very large and I thought they were compression fractures from the weight of the tree as it grows and so they they might just be a radical figuring. Please don't take this as fact as it is just a guess. I really do not know as I have only seen it once.

Have you tried flexing the neck to see if the wood moves strangely in those spots? A crack would be noticeable if you drag your nail across it but flexing it should make it more apparent. Maybe if you have any scrap you could test that out without risking a break.

Hopefully this is just a mineral streak of some sort. Let us know what you find out.

~David

[j. pierce]

I didn't think about flexing it to open it up - I had early tried to see how sturdy the neck was, and the neck itself barely seems to flex (I guess the carbon fiber is doing it's job) Maybe I can use the truss rod to induce some, but I'll paw through the cutoffs and see if I can't find more of this in some scrap and see what I can't tell from there.

The neck feels sturdy enough, but there's this part of me that imagines the whole thing snapping off and going flying when I string the thing up for the first time. Necks aren't glued in yet, so it's not too late to make a new one, I guess.

[jmrentis]

Maybe its like Myka was saying that under its own weight it cracked/fractured. It seems very likely but you said there is no actualy gap, so my thought was maybe at sometime in the growth is cracked, but eventually sealed itself up and kept growing, thus leaving no gap, but a slight dicoloration in the spot where it had initially cracked. If there isn't a gap and it feels solid and you have some cf rods and truss rod, I wouldn't imagine it snapping under the weight of strings, but if it was really a crack you will probably know shortly after stringing it up and those spots might open up and become gaps. Very interesting though, let us know what you find out.

EDIT: Maybe you can rig a quick jig that enables you to put some strings on in order to see how it reacts without having to glue it in. Like you I wouldn't want to put a neck in that could possibly crack in half, especially in glueing situations. Maybe drill a bridge to a piece of wood and sandwich the tenon with that wood on top and another on bottom using some clamps so you can throw some strings on it for a day or two and see what it does.

Edited June 26, 2007 by jmrentis

[crafty]

With carbon fiber and a truss-rod, I doubt you'll have any problems. There's less than 200 lbs. of pressure on the neck when it's strung up, so if you can stand on the neck it's plenty sturdy.

[erikbojerik]

I also think it is a compression fracture that has healed. I saw it once in brazilian mahogany that was destined to be a LP back; still sitting on my shelf.