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Post by Mitch on Jul 16, 2007 20:52:05 GMT -5
Does anyone know a good remedy to help stop Enamel chip. Iv got a tooth here that I would like to prevent chip and break on the enamel from happening. Does anyone have any ideas?
Mitch
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Post by harrypristis on Jul 19, 2007 19:18:38 GMT -5
What sort of tooth do you have, Mitch? Enamel (or enameloid on shark teeth) is very dense, but it will take on a consolidant. The dentin will absorb even more. I usually don't do anything with shark teeth, but here's what I do with mammal teeth sometime.
I use an infrared (heat) lamp to drive off any moisture, heating them for a few minutes until they are too hot to handle. Using forceps, I dip them in a solution of Butvar-76 and acetone. I leave them in the solution until they stop bubbling vigorously. I dry them on cardboard, turning them once if needed to avoid a "drip" on the tooth surface.
If Butvar-76 is not available, you can use Duco cement (the transparent model cement).
Acetone is a toxic, explosive solvent, so use plenty of ventilation.
---------Harry Pristis
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Post by Mitch on Jul 19, 2007 20:12:17 GMT -5
Thanks Harry. Im dealing with a rather large Great White tooth, the one shown in the picture on the Trip reports board. As its drying out it may begin to peel and I wanted to be prepared.
Mitch
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Post by harrypristis on Jul 20, 2007 10:26:21 GMT -5
That is a big carcharias tooth, Mitch, and I understand that you want it stabilized. I've never had one from the Waccamaw Fm in SC delaminate, but it does happen after the bourlette is eroded.
Here is something I posted on another forum some time ago. The fossil to be stabilized was in a crumbly shale. This technique works well with thoroughly-dry specimens whether in matrix or out.
<<Polyurethane will not give the desired penetration of the shale. Putting polyurethane on a fossil is usually a bad idea. I recommend against white glue (polyvinyl acetate) as a consolidant because there are better materials available. (Normal prep lab dilution of white glue is one part water to two parts glue.) A much better material for shale is a polyvinyl butyral plastic such as Butvar-76, but that material is hard to find in small quantities. I have used this plastic, dissolved in acetone, for many types of fossils. It works quite nicely on Silurian-age shales with brachiopods. It penetrates well, and it produces a "damp-looking" finish with no gloss. So, what works best? I recommend a solution of Duco Plastic Glue (clear, like model glue) in acetone. In a pinch, you can use a styrene plastic such as styrofoam dissolved in acetone. (I am not recommending this as I have no experience with styrene plastic. It is a tip I picked up years ago, but never needed to try.) Dilution? Start with a tube of glue dissolved in about four ounces of acetone in a glass jar. Shake well. Adjust the dilution with more acetone until, after shaking, the tiniest air bubbles are just slightly retarded in their rise to the surface. I usually heat specimens with an infra-red lamp to drive off moisture just before dipping the fossil. The specimen is as wet at the relative humidity of the air around it, I suppose. A microwave oven may be as effective, but give it some time. Do NOT heat the acetone solution. Ideally, you would submerge the dry specimen in this consolidant for a brief time (say 20-30 seconds, or until the specimen stops bubbling). Set aside to dry on cardboard (I use beer-flats). For a specimen too thick to be submerged, you can use a turkey-baster to flood the difficult areas. I use a RubberMaid cake-pan to hold the consolidant for this soaking step - that plastic seems to be impervious to the acetone. Acetone evaporates very quickly. Replenish the consolidant mixture with a bit of acetone if you are using it on many specimens. Store it in a tightly sealed glass jar. Even if some acetone evaporates away between uses (it always does, it seems), you can reconstitute the solution by replacing the acetone. Acetone is a nasty solvent. The fumes are explosive. The fumes are toxic. The liquid penetrates the skin-blood barrier. It's best to use gloves. Use in a well-ventilated area.>>
--------------Harry Pristis
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