Official Luthiers Forum!

Okay, my neck construction is a laminate design, with Purple Heart wood as the center. Now, after being planed down, it was a brown color, but after letting it sit for a while, it began to turn purple. However, now I've done construction and finishing in places, and not in others, but for the finished project, is there a way to have to a nice deep consistent purple color?

I did a little research, (check it out here: http://www.hobbithouseinc.com/personal/woodpics/purpleheart.htm and heat seems to have an effect of turning it a more deep purple, which was evident when I did some cutting with the bandsaw, and it got hot in certain places. I also read that some people have had success from putting it in the oven for 30min at 300 degrees, but I don't know if that would adversely effect the neck, warping, or drying improperly, or if the glue (I used regular wood glue to laminate the pieces together) would un-bond or anything like that. Anybody try this type of thing before?

I've got an oven for making fiberglass molds and that type of thing that would fit the neck, maybe heats to about 150 degrees, so that's an option as well. Thoughts? I'd really rather not screw up my neck at this point. Thanks!

I can't tell from your description whether the neck is laminated yet or not. You do state that some construction is done and some finish is applied. If your neck laminations are already glued up, I would NOT bake the neck. You'd just be asking for your glue to weaken. Others will probably have different opinions.

Oh sorry about that, yes, the neck has already been laminated. Even if I did bake it beforehand, sanding sections off would have made it brown again. I may just have to take the slow route and just be patient for a few weeks.

Freshly cut purple heart will have a washed out look compare to the color of the board prior to cutting...but the cut surface will turn a deeper purple after a while. I'm not 100% certain it's oxygen or u.v. that does it....but I'd guess it's oxygen.

Baking wood to obtain a darker color typically takes temps at 275F-350F when I do it with myrtle wood and maple. I wouldn't think 150F would be enough to accomplish anything although it's possible heated air helps it oxidize faster...idk.

Regardless of which glue you used....don't bake your laminated neck.

I just did some figured purple heart fretboards. After about a week they took the color of the original board.

_________________
I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

I figured that would be the case. I wonder if there would be a way to put it into some sort of oxygen enriched environment, if that would speed up the process. Anybody with a knowledge of chemistry, and reactions would release an immense amount of oxygen?

Stuart,
I think it's light, UV to be specific. I had some binding laid loosely on my bench and the parts exposed to light from a window turned deep purple, the shaded parts, which were exposed to air flow but not the sunlight, did not turn purple.
So to the OP, leave the parts in the sun and they should turn purple again.

_________________
http://www.CostaGuitars.com
PMoMC

I used to keep my wood in a shed. I also have lotsa purpleheart.
I did an experiment once. I cut and sanded some purpleheart and put it in the shed, in the dark, for about a month. I also stacked wood on top of some to see what happened.
All the stuff that turned purple was uncovered, and left in the dark.
The stuff that had wood stacked on it stayed brownish.
Whenever I've left it in the sun, it turns brown again after a while.

_________________
Old growth, shmold growth!

See like I said, oxygen baby!





Note to self: edit post about it being the sun that turn it purple.

_________________
http://www.CostaGuitars.com
PMoMC

Everything I or any of my colleagues has ever built with Purple Heart has turned a rather unattractive muddy brown after a few years, no matter what finish we applied. Seems to be UV degradation.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

Ditto.

Alright, so the general consensus is to try and use oxygen then? I had a thought, though. If I get some 6" diameter PVC with a couple of end caps, and cut a small hole in one end, and then use a welder's oxygen tank, and steadily bleed the oxygen in, that could be a good way to enrich the environment and let the wood turn purple. No leaving it in the sun, or anything like that! Thoughts?

I've read a hundred times that purpleheart oxidizes to a dark brownish color. The pretty color is nice while it lasts but if you want something to stay purple you should probably just dye some maple or something.

That's one reason I haven't played with it, because it doesn't stay purple.

_________________
http://www.tinyhouseandland.com

Yeah, it's a tough call. It's probably more about timing than anything else for finishing. I may give it a try and see how it turns out.

Careful you don't burn your place down, concentrated O2 can make stuff burn that would not otherwise.

_________________
Brian

You never know what you are capable of until you actually try.

https://www.howardguitarsdelaware.com/

I will keep that in mind!

I wouldn't mess with oxygen, too dangerous. It's actually more than combustible, it's explosive, and also toxic in high concentrations (yup, it's toxic!).

_________________
Old growth, shmold growth!

Early astronauts breathed pure oxygen. It was abandoned because of fires, not toxicity.

I don't swear by it, but a quick google check has several sites referring to oxygen toxicity only being a problem under pressure, like for divers.

Mike

_________________
Mike Lindstrom

Not technically explosive, it's actually an oxidizer ( ). Oxidizers don't actually burn or combust themselves but they make other combustibles (like purple heart wood?) burn. The higher the O2 concentration, the more rapidly something will combust. With a high enough concentration of oxygen materials can combust spontaneously, but that is generally from contact with liquid oxygen (I had to learn about the dangers of liquid O2 when I went through Hazardous Waste Operations training as an environmental consultant).

The concentration of O2 in the atmosphere is around 21% these days, but has been as high as 35% a few hundred million or so years ago. Not sure what concentration is dangerous, but that should give you an idea of what's safe. Without any means of monitoring the concentration I wouldn't even consider messing with it. And yes, in high concentrations oxygen is toxic (just like anything else that gets you high), but then again so is water, supposedly.

Science is fun! (And dangerous).

_________________
-—-—-—-—-—-—-
Mike Hoenerhoff
Elderly Instruments

I never drink water. too dangerous.

_________________
Old growth, shmold growth!

For a chemical reaction I would go with hydrogen peroxide. If you place your wood in a plastic bag or similar enclosure with a container of hydrogen peroxide mixed with blended raw liver -blended in the blender-, you will get an enriched oxygen environment. Body temp. will give you the fastest result and refrigeration will reduce it to almost nothing. Shouldn't be highly dangerous, but I would tend not to do it in doors, or near flammable materials.
edit: I would not store it in the fridge when mixed -would eventually fill fridge with oxygen-, but starting with your liver and peroxide cold will give you time to mix it before the reaction gets going.

I haven't used it on guitars, but I had the same problem with purple heart knife handles when I made those. Baking did the trick. I don't remember the temp, but knife blades are okay at temps up to 400 F, so that wasn't as much of an issue. I'm assuming all the nice purple boards at the lumber dealer are kiln dried. Don't bake your neck. The glue won't like it. Oxygen sounds like a good idea. The pvc pipe should work fine. You can breath pure oxygen with no problem. Divers breathe it down to 33 feet (twice the pressure here). Keep it away from sparks, and you'll be OK. Get it near a spark or flame, and a fuel source, and things will get interesting. Cigarettes are a bad idea. But ask any doctor, and they'll tell you stories of elderly smokers with emphysema, who breathe pure oxygen from a tank, and turn off the valve so they can safely take a few drags on a cig, turning the tank back on before they pass out.

I think it's potassium dichromate that is used as an oxidizer on mahogany. I haven't used it. It has a strong color of it's own, and might stain your other laminates.

"WudWerkr" on this forum has been building an acoustic guitar with back and sides of purple heart. I'd bet he's learned a thing or two about the wood. PM?

one other thing to consider is the ph. I recently did an experiment in responce to another thread that showed that both bubinga and koa change color with P.H. In both cases acidic conditions encouraged purple red and pink while basic conditions resulted in greens and browns. there may be other factors involved in your specific situation.