Never heard of this.......

[ScottR]

I went to pick up some sapele today and ran across something I never heard of before.

They had a dozen or so purpleheart boards leaning up against the building. The guy said they had turned brown on him (normal so far), so he had to bring them out into the sun so they'd turn purple again. It was always my understanding that the UV in sunlight was what turned them brown in the first place. I will admit the boards were indeed purple, albeit a lighter purple than the rich purple of fresh cut stuff.

 

Anybody ever hear of that before?

SR

[SwedishLuthier]

Agreed, never heard of. This is from the LMI site:

"the color will warm-up over time to a brownish hue (avoid UV/sunlight to maintain the purple color)"

[rhoads56]

Second time ive heard this in as many weeks.

I DID have some that went more purple with UV, and brown when freshly sanded.

But it would generally be the opposite way around.

[Tim37]

Is it UV turning them brownbrown, or is it oxidation?

 

If they where oxidizing that would be a decent explanation of why the purple returns

[ScottR]

Is it UV turning them brownbrown, or is it oxidation?

 

If they where oxidizing that would be a decent explanation of why the purple returns

Interesting points Tim. Perhaps oxidation also turns them brown. If UV turns oxidation back to purple, I expect it will ultimately turn that purple back to brown again.

SR

[Prostheta]

I'd call bullshit on this one if I were younger. The thing is, Purpleheart is one of a few different species. Depends on which one, and yes....UV/oxidation differences are a thing. I had a piece of old PH which went brown but returned to a deep dark purple after being scorched. Funny stuff, and one that has more opinion and peanut gallery activity than hard and fast facts. Probably because of the exceptions to the rule!

[Ripthorn]

I actually have a piece in my stash right now that does the exact same thing.  At first I thought that it looked like purpleheart, but not brownish as I expected.  I cut some up to make an infill plane, and the cut ends were brown.  Some of the offcut scrap that got left out turned purple.  I thought it was backwards.  However, I think what is really happening is that there are more than one species of tree called purpleheart, much like there are more than one kinds of maple, walnut, etc.  This purpleheart I have does not splinter quite like other purpleheart I have used (and that stuff was purple fresh and brown later).  So I think it is likely just that there are two species that both have purple heartwood, but that behave differently.  Then again, that's only a guess, but I have used purpleheart where the color shift goes both ways.

[ScottR]

Here is one of my favorite sources......with a whole lot to say on the subject:

http://www.hobbithouseinc.com/personal/woodpics/purpleheart.htm

Be sure to click on the "Fact Sheet"

Maybe one species was most commonly sold in the past and now a diferent species is the most common one on the market.

SR

[Prostheta]

Yeah, I've had some PH which went deep purple when cooked by the router. It was more common on the crappy bandsaw I was using at the time, since it was like trying to cut knives with butter.