Thread: Tortoise shell repair

I've disassembled a Frederick Reynolds faux frameback. I'm pretty sure the scales are real tortoise shell. They are warped away from their inner sides and one has a crack near the wedge pin. The wedge is lead and the crack did not go all the way through.

I'm not too worried about that crack; I can fill it and then with epoxy and then glue it down to the wedge for mechanical backup.

My questions:

1) What methods can I use to straighten these scales?

2) Am I taking the right approach to the crack? What glue will adhere tortoise shell to lead?

3) Can I put neetsfoot oil on the tortoise, or is there something better?

Many thanks!

I am pretty sure they are Horn, commonly called Mottled Horn...

There are a few ways to straighten them. Steam, Hot Water, Hot Air, all combined with pressure...

In the Workshop sticky are different ways laid out to employ those methods...

I have been having 100% success with my pressing boards lately..

Two pieces of Oak 3x9x1/4 inches drilled with many 1/8 inch holes, I put the scales in between the two boards and use c-clamps on either end and use the Shot o Steam Iron for a more noble use... Tighten them as I go then leave them alone for 24 hours after the scales are steamed straight... works wonders...

Originally Posted by gssixgun

I am pretty sure they are Horn, commonly called Mottled Horn...

There are a few ways to straighten them. Steam, Hot Water, Hot Air, all combined with pressure...

In the Workshop sticky are different ways laid out to employ those methods...

I have been having 100% success with my pressing boards lately..

Two pieces of Oak 3x9x1/4 inches drilled with many 1/8 inch holes, I put the scales in between the two boards and use c-clamps on either end and use the Shot o Steam Iron for a more noble use... Tighten them as I go then leave them alone for 24 hours after the scales are steamed straight... works wonders...

I was thinking the same about them being horn...but i'm not yet edumacated enough to say for sure...lol.

All the FR scales like yours I have seen are horn - it was treated with various chemicals (lye, quicklime, white lead, mecury) to make it look like tortoiseshell - in fact it was one of the most successful imitations of the time and known as mockshell.

Both horn and tortoiseshell are very similar in composition - both are thermoplastic and may be softened and shaped by heat (both dry heat and by boiling) - if the heat is too high the substance turns gelatinous - melts.

Tortoiseshell was built up in layers simply by fusing it together - the surfaces were rough filed, cramped together after being wetted and then heated. They stuck together in one piece, but water (in the form of steam) has to present. Even cracks were mended by cleaning the pieces, wetting the edges and pushing them together while applying a hot iron. The temperature had to be just right - the iron should be hot enough to just discolour writing paper, not burn or char it. The edges of the crack had to be scrupulously clean, too - no oil or dirt. I wouldn't recommend trying it except on something that wasn't wanted.

Seing as the chemical composition of horn and tortoiseshell are so similar, then I don't think that neatsfoot would hurt tortoiseshell - but I think those scales are horn.

Regards,
Neil

Originally Posted by Neil Miller

All the FR scales like yours I have seen are horn - it was treated with various chemicals (lye, quicklime, white lead, mecury) to make it look like tortoiseshell - in fact it was one of the most successful imitations of the time and known as mockshell.

Many thanks, Neil. I hadn't heard of mockshell. Sounds toxic. What sort of horn did they start with?

I just did the hot pin test on an old razor I have. It didn't smell like plastic. It actually had sweet smell to the smoke. Does that indicate anything?

Originally Posted by roughkype

Many thanks, Neil. I hadn't heard of mockshell. Sounds toxic. What sort of horn did they start with?

Ox or cow horn. Translucent or blond was best, but it could be bleached - or even coloured (earth colours like black, dark brown, dark red) by treating it with various chemicals.

When it was translucent it could be hot-pressed into large sheets and treated with tallow grease, then pressed again to make it more translucent - the result was lanthorn, used not surprisingly for lanterns.

Regards.
Neil