Straightening warped ivory

J

Jason Fry

Joined
Jun 5, 2008
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I've got a set of thin mammoth that's just begging to go on this super-thin Bird and Trout I'm working on. The knife started with 3/32 stock and is tapered both ways. The ivory is a little less than 3/16 thick at the crown, and there's about 1/16 of bow in each scale. Are there any ways to flatten ivory? Maybe boil and clamp? I'm afraid that if I thin them down the regular way by taking material off the back of the scales with the disk sander, they'll be too thin.

If there's no way to straighten, what's an acceptable liner material for an ivory knife? I'd want to thicken the scales a bit if I have to grind them flat. Without some kind of liners, the knife is going to be good to make it to 3/8 thick as it is.
 
Water and heat is bad news with mammoth ivory. Try to slowly flatten on your disc grinder if it gets too thin use it on one of your slip joints.


Craig
 
Craigb said:
Water and heat is bad news with mammoth ivory. Try to slowly flatten on your disc grinder if it gets too thin use it on one of your slip joints.


Craig is correct. No go on heat and water on any kind of ivory....not elephant, not mammoth, not hippo. not walrus, not warthog, not nuttin............
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Ok then... what liner material is acceptable with ivory? I've got red or black G10, and red, black, or gray fiber. The ivory is medium tan with bluish flecks. I got them flat the usual way, by sanding the back. Total maximum thickness without liners is .410. Is that too thin?
 
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Well I certainly don't believe that old wife's tail about mammoth ivory. I cannot say this for elephant or walrus or narwhale, but for mammoth, I usually start off grinding on it with a 60 grit belt and keep it cool by dipping in a 5 galloon pail of room temperature water. Even with other sizes of sandpaper I don't trust that I won't get it hot and dip the ivory frequently in the water. I have straightened many mammoth scales say 1/8" to 3/16 with a heat gun most often with a plate of steel two clamps and a tooth pick or a very small piece of wood. Sure you must go slow and don't try to do it in one time. Warm the ivory all over until you can't touch it comfortably but try not to go beyond this, tighten it with the clamps but only to take out the "soft" part of the bend. Let it cool and do again as necessary. Frank
 
Thanks for the input. I ended up sanding them flat. I am going to the Guild show, which is Loveless' organization (even though he's passed), so I went with his "lipstick" theory and did red liners. Got it glued up now.
 
Jason, did you go with g10 or fiber? I was going to say red G10, but I wondered what you decided.
 
I went with fiber. I've used the G10 several other times. The G10 is more "stable" supposedly, but the color just doesn't pop right like the fiber. Fiber was good enough for Bob :)
 
The mammoth ivory is antediluvian, it's been exposed to the elements for a long time,a little more water in your shop is not going to hurt it. Just let it dry completely before you use it.
 
I have steamed warped ivory to flatten it. I set up a pot of boiling water with about 1/2in of water in it. Put the ivory in a strainer on top. Steamed for 10 min and then clamped to a piece of PG steel. Let it dry for about a month before considering using it.
 
I've flattened it by soaking in vinegar untill it gets rubbery then clamping it between two flat pieces of wood. Like Chuck said let it dry for a long time.
 
Got it finished out this evening. This is the knife and crooked ivory that started this thread. Lin Rhea gave me this knife as a waterjet cut blank of 3/32 15n20. I did the rest :) OAL is 7 inches, blade is 3 1/4. Mammoth ivory and red liners on a tapered tang.
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