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  1. #1
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    real tortoise shell or plastic?

    Having just spent a fortune on new tortoise shell at Blade show, I was inspired to dig out some old previously used scales that I had been given as tortoise shell. (one set is a beautiful and unusual shape and has the liners with it as well and they dont look as if they were ever made up... anyone want to see?)

    So the question is - how to I know that they are real and not imitation? To be fair, it may be possible to date the strangely shaped one as pre plastic and they look right. Is there a test that is safe for the shell? (I don't care if it melts the plastic)

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    Re: real tortoise shell or plastic?

    If you were able to take a small scraping and apply a flame, I'd expect tortoiseshell to smell not unlike singed hair. This is a way in which proteinaceous fibres such as wool and silk can be identified from their man made imitators, so should work for the shell too...

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    Re: real tortoise shell or plastic?

    Same sort of test as for amber - hot needle.
    Peter

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    Re: real tortoise shell or plastic?

    Quote Originally Posted by PS_Bond View Post
    Same sort of test as for amber - hot needle.
    yes but won't that hurt the shell

    One of the troubles is that I dont know anything about the imitations. Was the pattern printed on the reverse? Mixed throughout the pale? What plastics were used (can I use a solvent to check?)

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    Re: real tortoise shell or plastic?

    A hot needle will damage both. It is my understanding that the UN banned the trade of tortoise shell in the 1970s when the primary source, the hawksbill turtle, was listed as an endagered species. A faux shell will look like the coloured patches are floating in clear plastic. A real tortoise shell will look a little like horn... opaque and transluscent. Hard to explain and show in pics.

    Modern Faux


    Old Genuine

    Last edited by Smiling-Knife; 27-06-07 at 09:20 PM.
    s-k
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    Re: real tortoise shell or plastic?

    A little google reveals that if plastic, it may be cellulose nitrate, or 'Celluloid i.e. the same stuff as movie film used to be made from.

    Try some nail varnish remover on it (sparingly)!

    http://www.noteaccess.com/MATERIALS/...oseNitrate.htm

    See this page, the paragraph to the right of Fig. 2:
    http://www.vam.ac.uk/res_cons/conser...ver/index.html

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    Re: real tortoise shell or plastic?

    Quote Originally Posted by grace horne View Post
    yes but won't that hurt the shell
    Afraid so, yes.

    Doesn't do much good for the amber either...
    Peter

    ethics (Noun, pl)
    1. a code of behaviour, esp. of a particular group, profession, or individual: business ethics
    2. the moral fitness of a decision, course of action, etc.

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    Re: real tortoise shell or plastic?

    True celluloid went out of fashion in the late 1940s. it was too unstable and extremely flammable.

    A good reference for the history of 'plastics' may be found at

    http://www.plastiquarian.com/
    Last edited by Smiling-Knife; 27-06-07 at 09:36 PM.
    s-k
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    Re: real tortoise shell or plastic?

    What I was pointing out to Grace was that a: If the material was Cellulose nitrate, it would be soluble in acetone, and b: Used sparingly, it shouldn't harm the material should it transpire to be real tortoiseshell.

    The links are there to qualify what I said since it was only gleaned from a bit of google-fu. I guess the celluloid reference is a total 'piquet rouge'!

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    Re: real tortoise shell or plastic?

    I'm still wondering whether I can sell my turtle shell!

    If you will a good edge win,
    temper thick and then grind thin.

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    Re: real tortoise shell or plastic?

    Can't you try sanding a corner or the back a little and smell it to see if it smells like plastic?
    Celluloid smells different (like moth balls supposedly but I've never smelt them so can't be sure if they smell like naptha or what.) and can outgas/rot which corrodes blades. It seems to depend on the colour as I've seen patches where certain colours have been with celluloid (orange?)

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    Re: real tortoise shell or plastic?

    Quote Originally Posted by grace horne View Post
    Having just spent a fortune on new tortoise shell at Blade show, I was inspired to dig out some old previously used scales that I had been given as tortoise shell. (one set is a beautiful and unusual shape and has the liners with it as well and they dont look as if they were ever made up... anyone want to see?
    Silly question

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    Do you have a leatherwork question? Try checking HERE to see if your question has already been asked.
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    Re: real tortoise shell or plastic?

    I'm really quite excited about designing a knife based around these scales...it'll be interesting to see just how contemporary it'll look given that the shape has been fixed.

    and with gold leaf under them, the colours look amazing.

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    Re: real tortoise shell or plastic?

    Quote Originally Posted by grace horne View Post
    I'm really quite excited about designing a knife based around these scales...it'll be interesting to see just how contemporary it'll look given that the shape has been fixed.

    and with gold leaf under them, the colours look amazing.
    Those are beautiful Grace. What are the dimensions? Thanks
    s-k
    Rust Never Sleeps

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    Re: real tortoise shell or plastic?

    Quote Originally Posted by grace horne View Post
    I'm really quite excited about designing a knife based around these scales...it'll be interesting to see just how contemporary it'll look given that the shape has been fixed.

    and with gold leaf under them, the colours look amazing.
    Cut throat razor scales?

    Danzo

 

 

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