real tortoise shell or plastic?

[grace horne]

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)

[underground]

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...

[PS_Bond]

Same sort of test as for amber - hot needle.

[grace horne]

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?)

[Smiling-Knife]

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

[underground]

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

[PS_Bond]

yes but won't that hurt the shell

Afraid so, yes.

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

[Smiling-Knife]

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/

[underground]

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'!

[imagedude]

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

[murphy]

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?)

[Tiffers]

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

Tiffers

[grace horne]

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.

[Smiling-Knife]

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

[Danzo]

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