Lignum Vitae color change at cure

[Mike L.]

So I had a couple of blocks of lignum vitae that were dark green after aging, a process I accelerated with a UVA light tube I made to speed up the process a bit.  As you can see, the lignum was a nice deep green before curing, and then I glued them up with a nice chunk of figured mango and after curing at 170 for 4 Hours,
The lignum bled oil everywhere and turned brown again.  Didn’t see it coming.  So should I wipe it off with mineral spirits and put it back under the lights?  Is the green color ever coming back?  Also what about the glue joints?  They seem solid but that oil pooled up all over.  Wonder if it compromises the bond.  Anybody have some thoughts?

[Mike L.]

Oops.  Meant to send this one too.

[Mad Max]

Osage turns dark over time, but only on the out side, if you sand off the outside it goes back.
After you finish the bow is when you should use UV light.
I don't know anything about the wood you have

[Flem]

I think the brown looks nice, but I realize that was not the look you were going for. That Ironwood is known for being oily. I think I would try what Max suggested, UV after glue up and maybe cook that epoxy longer at low temperature.

[Buemaker]

I would not cure this wood with heat, just room temp. To much oil in this species. Was among other things used for boat propeller bearings and needed no grease.

[Shredd]

All I know is that it is one of the hardest most dense woods in the world and it's oily and it is very hard to come by and I believe it is now protected... I agree with Max and Bue...  I personally stay away from oily woods when building a bow... But then I am more after function than aesthetics...

[Shredd]

If it ages to a green, what's the rush??  Just make the bow and it will turn green over time...

[Mad Max]

UV after completely finished is what I met to say

[Mike L.]

Makes sense.  I wonder if the glue will hold.  If it turns green again it’ll just be a bonus.   I figured the density and weight would make it perfect for a riser.  I’ll know next time to cure it at a lower temp.   I knew it was a rare species, but I just bought it a couple of years ago; no idea it was protected. 

[garyschuler]

This stuff is very hard and yes was used for support bearings in ships and lumber mills, made great saw guides for mills. I dont think i would use it in bow building.
But you don't know until you try. Definatly would cure at room temp of low heat.
Good luck and let us know how it turns out.
They said you can't make a bow out of OS Bamboo flooring, thats been debunked!

[Mike L.]

I’m going to give these two a try.  Both are lignum vitae and mango, one will have mango veneers and the other will be Australian curly walnut I hit with some green and grey dye yo match the green in the lignum vitae.  Both these risers produced a ton of oil when I cured them at glue up (ea40 170 for 4 hrs), so I was concerned about the glue bonds (and the color) but the bond seems fine as far as I can tell.  I’m going to try 2 64” R/D’s, one with the belly glass all the way through.  I also have one of those fake snake skins I might try on one of them just because I want to see how it looks.  From what I understand you glue them on outside the glass and can take it off later...

It was recommended not to cure the glue so hot to avoid bringing out the oil. Do you guys think I should use lower heat or no heat and 24 hour cure?  I’m using a fire hose press and silicon heat strips.   I usually rough up gluing surfaces and then wipe down with denatured alcohol prior to gluing.  Would acetone be better?

[Flem]

If you have a thermostat on those heat strips, you can cut the cure time in half by raising the temp 18deg. over room temp, which should not cause oil seeping issues. I would not use acetone, it can draw oil out of the wood. I stopped using solvents on wood altogether. I vacuum, then blow with dry compressed air.

What happened to your other glue-up?

[Mike L.]

These are the same ones, so far nothing happened, I was just really surprised by how much oil leaked out of the lignum vitae; each riser had a puddle of oil underneath and it was dripping pretty steady. I was worried it might have compromised the bond, but they both seem to be solid.  I don’t know of a definitive way to check, but at least they seem solid and I’ve handled them quite a bit.  It’s a really interesting wood, and I love the green color. 

[Mike L.]

Would denatured alcohol be a problem, do you think?

[kennym]

I never put any chemical on wood to be glued either, just fresh grind and glue up.

My hunting bow (til January this year ) I used for 5 years and cured with no heat on it, 24 hours at 70 ish in shop just to see. No probs...

[Mike L.]

Kenny, do you always use around 70psi on the hose?

[Mike L.]

I’ve been stopping at about 55 psi.

[Flem]

Would denatured alcohol be a problem, do you think?

Not on most woods, but I would not risk using even a mild solvent like denatured on oily woods.

[kennym]

Yes, but with the amount of glue that squeezes out at 10 psi before I remove the ziptys, and the amount when I go on to 70 psi,  I think 55 is plenty.  Not a whole lot more at 70 than 10 comes out.

I know a lot of folks run in the 50-60 range

[Mad Max]

On you dry run if the gaps closeup at 50psi that's all you need