"removable Preservatives" On Fossils

[cowsharks]

I'm interested in making a cast of a fossil shark tooth, but I'm faced with two problems:

1) the material that is used to make the cast/mold has oil in it, and during the process of making the cast, some of the oils could get absorbed by the porous root of the shark tooth. The root is a light color right now and I want it to stay that way. If oil(s) get into the root, it will darken the root and take away the nice light colors it has now.

2) research shows that I could paint a preservative of some sort over the root (or whole tooth) to prevent the oils from the casting material from getting into the shark tooth, but the problem with that is I'm not sure if the "preservative" can be easily removed without being forever absorbed into the root/tooth or itself leaving oils that would darken the root/tooth?

I do have some "junk" teeth to practice on, so please let me know if anyone has suggestions on how to resolve this problem. I want to "protect" the originality of the shark tooth as much as possible and don't want to darken it during this process.

thanks,

Daryl.

[Fossil Claw]

http://www.thefossilforum.com/index.php/topic/3629-preserving-fossils/?&hl=acryloid

[Wrangellian]

I would try the thin solution of vinac/butvar/paraloid, though I have not done it before so can't give you tips from experience, but these things are removable with acetone they say. Maybe a thin enough solution would not obscure too much of the surface detail and be easy to remove? I only wish I had thought of the oils(?) in latex when I went to make a cast of a bivalve negative that I have, which is now darkened. Not that I care like you do about the color, but what do these oils do to the shale over the long term? Now I wish there were something I could submerge it in that could remove the oil like you do with butvar/vinac in acetyone....

[cowsharks]

I wonder if I covered the entire tooth and root in a coat of Elmers glue if that would protect it from the oils in the cast/mold process, and then just remove the Elmers afterwards by soaking in water and scrubbing softly with an old tooth brush?

I might experiment with a junk tooth; paint on a coating of Elmers glue, let it dry completely, test to see if it will repel oil(s), then see if I can remove the Elmers glue and have the tooth dry out back to its original coloring.

[minnbuckeye]

Wrangellian has the proper advice. I have used butvar to protect specimens for multiple reasons, even a little acid treatment. It cleans off easily with acetone leaving the fossil looking as it did initially. I think this will go on much thinner than elmers glue diluted, hence providing far more detail than with glue. Try a test tooth each way and post the results. it would be interesting. Good luck either way!

[Opisthotriton]

Standard Elmer's glue is not reversible. It will not dissolve again. The "washable" kind might soften, but I don't know if it would remove cleanly, or leave white areas in the crevices.

Vinac/Butvar/etc might also change the color of the fossil, making it appear slightly darker or "wet". Rubbing acetone over the surface afterward would remove the surface "wet shine", and should reverse any darkening.

[toolbox82]

I have used a light coat of clear silicone di-electric grease to cover some fossils. Please test on one of your "junk teeth" to see the result first.

[Ludwigia]

A beeswax finish could also work, since it's easily removeable with acetone.

[Auspex]

It is still in its technological infancy, but 3-D printing would not alter the original at all. Whether it would achieve the desired results, though, is another question.

[cowsharks]

Thanks folks, these are some good suggestions. I'm going to practice on a few junk teeth after I get some butvar.

[cowsharks]

On this website, they list the following types of Butvar, but I didn't see an explanation of what the differences are. For putting a layer on a shark tooth to protect before a cast is made, and then remove the butvar afterwards using Acetone, which Butvar would be good to use?

White, free flowing powders. Generally soluble in alcohols, acetone and aromatic hydrocarbons. Forms films similar to polyvinyl acetate and is suggested as picture varnishes. Widely used to waterproof textiles. The films resist degradation by sunlight and heat. Average molecular weight is 30-34,000.

F4503-001 B-76 1 kilogram $34.00

F4504-001 B-79 1 kilogram $31.09

F4505-001 B-90 1 kilogram $25.08

F4501-001 B-98 1 kilogram $46.12

Edited August 30, 2015 by cowsharks

[Opisthotriton]

Butvar B-76 and Butvar B-98 are both used in paleontological preparation, but I can't find my reference for which of those two should be used in what type of situation. Every formula is different, so make sure you get the right Butvar. The other numbers will not be what you want. (Of course, just our luck, Butvar B-76 and Butvar B-98 are the expensive ones!)

Maybe JPC can find a proper reference.

Also, these "B-" numbers can apply to many different types of plastics, so you should always use the full name and B- number whenever you're talking about them. Butvar B-76, Vinac/McGean B-15, etc.

[jpc]

I see i have been summoned....

Amy davidson from the AMNH did a poseter on different uses of different consolidants. I don't have the link with me here at home. Mybe i will see if incan find it at work.

EDIT: Here it is: LINK

Edited August 31, 2015 by Auspex
Adding link

[cowsharks]

Thanks JP, etal, I'll check it out.

[mako-mama]

Daryl,

Vinac will darken whatever it is used on...sometimes it's a nice touch. But on shark teeth, prob a no-no. If your roots are white, they should already be Butvared to preserve them....such as those at Lee Creek Yorktown, Bone Valley or Shark Tooth Hill.

Butvar76 is a plastic. It absorbs into the tooth root. Oil will not penetrate that. If you feel you must remove the Butvar76 later (I don't recommend that), a good soaking of the "root only" will soften and dissolve it.

If the crown of your tooth has cracks, they should be treated with Butvar as well or the oil will soak into those crack. It won't hurt anything but will change the way the tooth looks.

I do sometimes use Vinac but for bones only. It gives them a very nice color. But like you, I dont want the root color of my shark teeth altered.

Pat

[ZiggieCie]

Here is a great link for preservatives and how to use and mix them.

http://www.connectingtocollections.org/wp-content/uploads/2014/02/Davidson_and_Brown_2012_Paraloid_B-72-_Practical_tips_for_the_vertebrate_fossil_preparator.pdf

Here is a supplier I have used.

http://www.conservationsupportsystems.com/product/show/acryloid-paraloid-b-72/acryloid

Ziggie