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Purpleheart color change..

Discussion in 'Luthier's Corner' started by throbgod13, Sep 29, 2009.


  1. throbgod13

    throbgod13

    Mar 26, 2005
    Texas
    i've read about how purpleheart changes color.. from violet to a ruddy brown.. apparently, it's from a chemical change in the wood.. i read that if you heat the wood up, it will change back to violet.. but, it has to be a temperature around 450 degrees F..

    i have a Conklin GT-7, and the fretboard and laminates in the neck have went brown.. on a lark, i used a 1200W hair dryer on full blast on the neck..

    and no kidding, i can see the violet shade coming back.. it's not completely violet, but the color has come back to a noticeable degree.. i.e. it's not rust brown, it has more of a violet shade to it now..

    i'd use a heat gun, but i'm afraid to stress the glue..

    i'll take some pics.. i do have some before pics to compare..

    i'm not sure if it's UV that breaks down the chemicals in the wood, or if it's just a normally occurring thing with purpleheart..

    heat will bring the color back, though..
     
  2. stevetx19

    stevetx19

    Sep 28, 2006
    Denton, Texas
    ...wait...you put your hairdryer on full blast on a finished bass neck...a nice bass like a conklin? and it worked? :eek:
     
  3. I was told it's like metal rusting. Purely oxidation of the wood. I have a P-bass with a purple heart top that is a dark maroon color.

    H
     
  4. Cy_Miles

    Cy_Miles

    Feb 3, 2005
    Here is what PH looks like after cutting.
    3513918846_899a84c951.

    Here is what it looked like a couple days later. You can't really see it here, but I have seen dark sap spots seep out of the poors if the wood is left alone after milling.
    3530421288_2446ca04da.

    After a week or two it became a very deep purple, to maroon/burgendy, depending on the light. In a yellowish light it looks more maroonish. In a white light it is more purple.

    Here are two pics from the same camera just seconds from each other. The "white balance" on the camera made the ph seem different in the two pics, but not unlike how it appears to me at different angles.
    3593412309_50d9e1d19c. 3593412317_866c88bc04.


    And about heating the ph... Another TB denizen suggested putting it in the oven. So after a google search I put a piece in the oven at 140 F. The first pic is after 15 minutes, notice the dark sap soaking out into the wood.
    the second is after 45 minutes. (the smaller piece was cut off and not cooked, as a control piece, again, see the "white balance" color tone affect.
    3529441561_a56892fea5.
    3529441563_1a9b1457f1.
     
  5. throbgod13

    throbgod13

    Mar 26, 2005
    Texas
    well.. all i can say is that the FB was brown, and after i hit it with the hairdryer it became more violet.. i'll post pics..
     
  6. mikeyswood

    mikeyswood Banned

    Jul 22, 2007
    Cincinnati OH
    Luthier of Michael Wayne Instruments
    Interesting. I can say that the browning in Purpleheart is from autoxidation of the oils in the wood itself. It is a process that can only be stopped by removing ALL oxygen which may cause breathing problems.

    I am fascinated by the heating process and I wonder if that is heating up more fresh oil to the surface...

    Cy - After your oven piece turns brown would you heat it up again? My thought is that it will be a decreasing solution.
     
  7. Cy_Miles

    Cy_Miles

    Feb 3, 2005
    autoxidation???? is that still legal?

    seriously, I am not convinced that it is oxidation, (auto or not) is what is behind the color change. Some seemingly knowledgeable wood websites have suggested it was do to UV. I am not convinced of that either.

    When I heated that piece of ph, it turned deep purple throught the piece, and seems to have stablized that dark purple color. That was several months ago and it has not changed color to any appreciable degree.

    And I disagree that PH turns brown. It turns very dark after time, but I still see it as a deep purple, maybe a maroon or burgundy. In my experience it starts brown and turns purple, and then just gets darker.

    The ph in my bass is actually two tone when you look at it up close. A bright reddish purple irridescents mottled together with the darker (ok ruddy brown) sap spores. Together it makes a color that is certain light/angles looks more purple and other light looks more maroonish. But I would never call it brown.

    And remember, they say a large % of men are color blind.... :ninja:
     
  8. throbgod13

    throbgod13

    Mar 26, 2005
    Texas
    from what i've read, it's not an oxidation process.. it seems that there are over 20 different types of "Purpleheart" wood..

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

    this has pics of cooked purpleheart.. but the specific types aren't denoted.. i think that's why some planks came out more violet than others.. it could also be from where the planks came from in the tree.. i.e. more sap, deeper violet during the cooking..

    i'm not saying that my neck turned violet, but the color is much more apparent than it was before.. prior it was just a ruddy brown.. now, you can see a more violet tone to the brown..

    i might subject it to direct UV.. i.e. a tanning bed.. to see if it turns more violet..
     
  9. Stealth

    Stealth

    Feb 5, 2008
    Zagreb, Croatia
    Let's just hope there's a positive link between UV light and the purple tint, and that it's repeatable forever - akin to phosphorescence. Otherwise, at one point the purple-heart will lose the color and that, sadly, might be it.
     
  10. throbgod13

    throbgod13

    Mar 26, 2005
    Texas
    that would suck.. but it does look pretty nice as a tea colored wood with blonde in it.. but it doesn't look nearly as dramatic as violet does..
     
  11. Getaway Driver

    Getaway Driver

    May 31, 2009
    Omaha, NE
    Does finishing PH in a certain way effect this? I suppose oiling it for use as a fretboard would leave it more susceptible to oxidizing, but would lacquering it seal the wood enough that it wouldn't change?
     
  12. Cy_Miles

    Cy_Miles

    Feb 3, 2005
    do you know this from first hand experience or is this something you've read or been told. :confused:

    Because my understanding is that it will get darker. I'll have to come back to this post in a year or two and give you a report on my ph. Which to this point has just got more dark, but I would not call that loosing it's color. Just going from a brihgt violet purple to a deep maroonish purple.

    Why would oiling wood make it suseptable to oxidization. :confused: I don't know about plant oils, but I am sure the mineral oil I use on the necks protect it from the air.
     
  13. mikeyswood

    mikeyswood Banned

    Jul 22, 2007
    Cincinnati OH
    Luthier of Michael Wayne Instruments
    You cannot be serious. Oils "dry" because of oxidation. Oils do not prevent oxygen from getting to the wood. Nothing does. Oxidation is part of life. Cy I hope that I missed the sarcastic inflection.

    The only way to prevent a material that oxidizes is to remove the oxygen. But that may make it a wee bit tougher to breath.
     
  14. throbgod13

    throbgod13

    Mar 26, 2005
    Texas
    BEFORE..
    DSC_1186.

    AFTER

    DSC_1216.

    DSC_1217.

    DSC_1219.

    DSC_1220.

    it seems to be more apparent than before.. it's not violet, or really purple, but it's more than it was before.. i figure if i leave it outside in the sun for awhile, it might turn a deeper violet.. maroon would be just fine too..

    i know it's not a dramatic change, but if i keep doing what i'm doing, hopefully it will be more violet/maroon than the rusty brown it was..
     
  15. BassBilodeau

    BassBilodeau

    Apr 2, 2007
    Sherbrooke, Qc, Canada
    Builder of Bilodeau Basses
    I have never seen purpleheart changing to rusty-red color.

    I don't want to drop oil on fire, but it does not look like a purple heart fingerboard.
     
  16. mikeyswood

    mikeyswood Banned

    Jul 22, 2007
    Cincinnati OH
    Luthier of Michael Wayne Instruments
    The grain and color appear to be Purpleheart. What do you see to think that is not?
     
  17. Cy_Miles

    Cy_Miles

    Feb 3, 2005
    I did not really mean any sarcasm, I just thought the purple emoticon was germain to the topic. And I was sort of confused. :confused:

    About the oxidization, I tought that oil would keep out the oxygen. That is why you are not supposed to put butter on a burn the way my grandma used to.

    I did a little google search and found an article that parralels what I had learned before, and why I use mineral oil on my FB instead of lemon oil .like many people do.

    At Woodenflute.com their is an article that is similar to an article I found about bagpipe maintanance.

    The crux of the article is that most oils do oxidize, but that mineral oil has a completey different structure and "there is essentially no mechanism for air oxidation of mineral oil".

    So looks like we can both be right on this one. :hyper:
     
  18. Stealth

    Stealth

    Feb 5, 2008
    Zagreb, Croatia
    Not from personal experience, something I read long ago and now can't recall the source. I haven't actually paid attention to any of my instruments (none are purple-heart - and only one is oil-finished mahogany) changing color - then again, no instruments of mine see the light of day that often. What I'm saying is - I'm not sure if wood would darken from UV exposure or from lack of it, but I hope you can do it indefinitely every time the purple-heart loses its luster and color.

    You might very well be right and it might just keep getting darker and more purple - if it does, excellent. That means my long-term planning to get a purple-heart instrument will pay off. The purple's where it's at. :D
     
  19. Cy_Miles

    Cy_Miles

    Feb 3, 2005
    This pic I found and borrowed off of craigslist shows how many different shades ph can take on with time.

    I am going to venture a guess that it largley has to do with the grain and what part of the tree the wood came from.

    3968462746_4f2a84e53f_o.
     
  20. mikeyswood

    mikeyswood Banned

    Jul 22, 2007
    Cincinnati OH
    Luthier of Michael Wayne Instruments
    SWEET!! Practical use of chemical knowledge!!

    Butter on a burn has nothing to do with oxidation. Butter is composed of ~46-60 carbon length chains which means that it is large enough to be a fat; which in turn is an insulator. Butter on a burn will prevent the exhaustion of heat thereby increasing the intensity of the burn.


    All oils oxidize. The oxygen will link at the end of the carboxy side. I believe that what you have noticed with the mineral oil is that it is mostly hydrophobic which will keep water away. By keeping the water away it will reduce the frequency that water will intrude (bringing oxygen) and slow the oxidation.

    Mineral oil will reduce the speed of oxidation but not form the protective coat that other oils do.

    I can respect that guess. My guess is that the glue-up shown is comprised of pieces from different trees which could be separate species within the amaranth group.
     

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