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Hippo Ivory Preparation


Mark

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HI everyone. This is my first post. This is my first attempt at carving ivory. I purchased a piece of hippo ivory and have cut it to a smaller length for my piece. About half of the tooth has the nice ready to go Ivory that is manageable to carve. However about half the tooth has a harder grooved outer layer that is really hard to carve. Does anyone know of an easier method of removing this hard outer layer to get to the chewy easier to carve center? Thanks and any help greatly appreciated. Mark Lustigm@verizon.net

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As I understand it, you want to remove the bark. A belt sander, using the slack part of the belt should help get rid of the outer layer. Start with a medium grit and watch the aggressiveness. I'd hand sand with the finer grits to avoid burning the material. You could hand sand entirely, but it will take longer. Hope this helps.

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The hard part is the enamel of the tooth - what you want to carve is the interior ivory or dentin. I soak the tooth for about 30 minutes in muriatic acid (used in the construction industry for cleaning concrete and brickwork - is an industrial grade of hydrochloric acid). The acid will dissolve the enamel. Obviously the acid is a hazardous material, so you should handle it with care, outside, rubber gloves and eye protection. Don't leave the acid inside your studio/shop since outgassing will cause all the steel in the place to rust, even with the cap sealed.

 

The bad part is the surface of the ivory will be attacked as well, and will be sort of gooey/sticky. I use a scraper to remove all of that and get down to the good carving material, followed by a short soak in baking soda/water or household cleaning ammonia to neutralize any remaining acid. Ideally, you should wait several days before continuing to carve. Any gooey spots you've missed should show up as darker areas by then.

 

Don't try to cut the ivory with the enamel still on with any power saw - the enamel will ruin the blade, as my bandsaw can attest.

 

Power sanders can slowly remove this very thick enamel, but you need to be careful about heat buildup, as this will ruin the immediate ivory layer underneath. Don't breathe the dust this will produce...

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The hard part is the enamel of the tooth - what you want to carve is the interior ivory or dentin. I soak the tooth for about 30 minutes in muriatic acid (used in the construction industry for cleaning concrete and brickwork - is an industrial grade of hydrochloric acid). The acid will dissolve the enamel. Obviously the acid is a hazardous material, so you should handle it with care, outside, rubber gloves and eye protection. Don't leave the acid inside your studio/shop since outgassing will cause all the steel in the place to rust, even with the cap sealed.

 

The bad part is the surface of the ivory will be attacked as well, and will be sort of gooey/sticky. I use a scraper to remove all of that and get down to the good carving material, followed by a short soak in baking soda/water or household cleaning ammonia to neutralize any remaining acid. Ideally, you should wait several days before continuing to carve. Any gooey spots you've missed should show up as darker areas by then.

 

Don't try to cut the ivory with the enamel still on with any power saw - the enamel will ruin the blade, as my bandsaw can attest.

 

Power sanders can slowly remove this very thick enamel, but you need to be careful about heat buildup, as this will ruin the immediate ivory layer underneath. Don't breathe the dust this will produce...

 

Thanks very much Tom. I am on the way to get some acid and a replacement Dremel bit or 2. Thanks for making a tough job easier. Once I start carving, I will be posting progress. Mark

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Hey Clive,

 

I guess I've been going about this all wrong....

Should I retire my rifflers, files, gouges & chisels???

Trade them in for an industrial grinder and the like?

Oh dear, am very concerned now..... ;);)

 

Regards,

 

Kathleen

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Guest ford hallam

actually, I'd second what Clive said.

 

I have a piece of hippo incisor which has enamel that is like bulletproof glass. I eliminated it with an angle grinder. It stinks to high heaven and makes loads of smoke and sparks!....and the hippos really struggle at that point ;) , but it beats getting all slimey and is quick!

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Guest ford hallam

Hi Doug,

 

I am only familiar with the tushes ( sic ) of our local warthogs and these don't have any enamel covering, they are just like elephant tusks in that respect. But if the sort you are talking about do then I'd just suggest that you don't hog off ;) too much of the outer layer when preparing them for carving.

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Hiya Katjleen.. long time no speak.. u well I hope.?

 

As far as the question goes... my approach is always to do what does the job most directly.. lifes too short to be messing about with fancy shit there being so much other stuff that does require serious considerstion. I geuss half the battle is learning what is important and what isn't... but thats a each to her/his own journey thingie sort of subject.

 

Aye up Doug... Naa... the enamel on pig (boar) tusk is a lot softer than hippo and obviously since the tusks are a lot smaller a lot less work. Well thats if you want to get rid of the enamel.. personally I love the contrast between the two materials and take advantage of it wherever possible

 

Ford... your local warties do have enamel on thier toothies just not very much.. the prefer to headbutt any scallies.

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Hiya Clive,

 

Yes, I'm quite well thank you. No complaints and who would listen anyway? :) I trust you're keeping well yourself? I would hope at any rate.

 

Ahh, you're quite diplomatic in your response. I'll continue on as is then. Personal preference would be my arguement as to choice. :) Yes, there is far more important stuff to consider...am rather deeply involved with that at the moment. :D

 

All the best,

 

Kathleen

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Hi Mark...

 

Hippo ivory comes from that animals lower canines and incisors. It varies in size depending on the size of the animal. The lower canine is curved and has a triangular cross section; the incisor is straighter and has a circular cross section. Its basic structure is the same as in most animals... a pulp cavity, a softish material called cementum which lines this cavity and the outer root section, then the dentine which makes up the body of the tooth and which is covered by the hard protective enamel

 

It is the dentine that you have recognised as the soft inner material. However the dentine has two layers: an outer, primary dentin, and an inner, secondary dentin. The innermost layer has a marbled appearance, which differs by species, and can even appear to have a greenish cast. The cementum material is slightly softer than that of the dentine and often has a deeper yellow creamy appearence.

 

I've used hippo ivory extensively over the years and have tried various methods of removing the enamel. As I mentioned earlier an industrial grinder with a masonary disk is my prefered method. Obviously a nice new disc will cut through the enamel better than a blunt old one... producting less heat which as has been mentioned will burn or crack the underlining dentine.

 

If you have any more questions please don't hesitate to ask.

 

Clive

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  • 2 weeks later...
Power sanders can slowly remove this very thick enamel, but you need to be careful about heat buildup, as this will ruin the immediate ivory layer underneath. Don't breathe the dust this will produce...

 

Tom pointed those very important issues and although Clive's solution seem to be the easiest and most likely best to keep the material intact do bear in mind that most enamel and dentin matrix of most teeth in the animal world is hydroxilapatite (a.k.a hydroxiapatite) and that reads pretty much a calcium phosphate ceramic. It's certainly not silica but if you breathe it the mucose of your lungs and sinuses won't like it very much and might cause chronic problems if you sustain exposure to it for long enough. So if you plan on working often with it it's probably wiser to weaken it with muriatic acid, fluoride concentrated solutions will also cause it to break in bits as it does with teeth when they are in mouth but on a hippo tooth it could certainly take a while longer.

 

As for having enough material to carve after the proceedure it should not be a problem, most dentin to enamel ratio in provide for plenty leftover.

 

Sorry about the dentistry insight, it is perhaps the only bit I can talk about with more knowledge at the moment.

 

Regards

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Well of course, it is about equality amongst everyone and for everyone (but him), and if you refer to the zoo that would probably be another name for his government cabinet, so most likely that hippo would probably be the minister of education hahahaha.

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