How to Preserve Fossils

[JohnnyFlake]

I have heard of special sealants that can be purchased to brush onto fossils that will help preserve them, but that they are crazy expensive for what you get. I have also heard/read of people using Elmer's Glue to coat the fossil, as it dries clear. I have also read that some collectors use a form of spray shellack or other clear spray type sealants. One person mentioned using clear nail polish.

I am a little unsure as to what will work and what will not. Any and all comments and suggestions will be appreciated.

 

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[GatorBoy]

If it is completely fossilized you shouldn't need anything.
If not.. all I use is white glue and water.
You don't brush the glue on since that would only coat the outside leaving the rest to deteriorate.
Thin it down to a consistency not much thicker than whole milk(about 1 part glue to 10 parts water) and soak the item in it overnight.. 24 hours.two days....ect.. depending on the size of the object.
You want it to penetrate the entire thing.

 

[GatorBoy]

Works well on old bone artifacts also.

 

[JohnnyFlake]

If it is completely fossilized you shouldn't need anything.
If not.. all I use is white glue and water.
You don't brush the glue on since that would only coat the outside leaving the rest to deteriorate.
Thin it down to a consistency not much thicker than whole milk and soak the item in it overnight.. 24 hours...ect.. depending on the size of the object.
You want it to penetrate the entire thing.

Thanks GatorBoy

What is "white glue"? Is it sold, named as such, "white glue"?

 

[roygpa]

Elmer's glue is white glue.

 

[Harry Pristis]

Here is a workable technique for consolidating fossils.

Polyurethane and other spray coatings will not give the desired penetration of the fossil. These resins are very difficult to remove. Such coating 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.) Rarely, a specimen cannot be dried without it crumbling, and white glue is the only reasonable answer. In my experience, white glue is messy and never looks good when the specimen is fully-prepared.

A much better material for bone is a polyvinyl butyral plastic such as Butvar B-76, but that material may be hard to find in small quantities. I have used this plastic, dissolved in acetone, for many types of fossils. (I have used it successfully on Silurian-age shales with brachiopods, for example.) It penetrates well, and in the proper dilution it produces a "damp-looking" finish with no gloss.

Butvar B-76 (but not other Butvar varieties) is also soluble in alcohol. (I assume that is denatured alcohol that you can buy in gallon cans.) I have never tried this solution for consolidation. The alcohol takes considerably longer to boil off the treated specimen.

So, what is the best choice? [most convenient, if you don't have Butvar-76] I recommend a solution of Duco Cement (clear, like model airplane glue) in acetone.

Dilution? Start with a tube of glue dissolved in about five or six ounces of acetone in a glass jar with a metal screw-top. Shake well. Shake some more ... it take a while.

Adjust the dilution with more acetone until, after shaking, the tiniest air bubbles are just slightly r*tarded in their rise to the surface.

I usually heat specimens with an infra-red lamp to drive off moisture just before dipping the fossil. I do this with all sorts of fossils, and have never had one damaged by the heating. The untreated specimen is always at least as wet at the relative humidity of the air around it, I suppose. (A microwave oven may be as effective, but I've only dried glass beads for my air-abrasive unit.)

Do NOT heat the acetone solution directly. The acetone solution will get warm after dipping a number of heated fossils. You must have good ventilation to deal with the fumes!
I use a long-jawed forceps -- ten-inch tweezers, really -- to dip and/or retreive the fossils from the jar.

Ideally, you would submerge the dry specimen in this consolidant for a brief time (say 15-30 seconds, or until the specimen stops fizzing). Set each wet specimen aside to dry on cardboard (I use beer-flat because that cardboard is absorbant and doesn't readily stick to the fossil).

To avoid pooling of consolidant which may want to drain from a bone, I rotate the bone once or twice in the first minute or two after placing it on the cardboard. This helps avoid a "drip-bead" of consolidant near the lowest point of the bone.

For a specimen too thick to be submerged, you can use a turkey-baster to flood the difficult areas. I treated an adult mammoth tibia that, because of its size, I dried in the Florida sun, then used the baster to pump consolidant into every opening of the bone.

I use a RubberMaid-type cake-pan to hold the consolidant for this soaking step - that plastic seems to be impervious to the acetone. Get 'em at your local dollar-store.

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

* Here's what 'oilshale' had to say about white glue:
"Don't get me wrong - Elmer's White glue is a great stuff for glueing wood and can be also great for "hardening" crumbly fossils!
"But I fully agree with Harry's opinion (even so I am a polymer chemist and my job is to develop white glues and other latices....): I would never use a white glue unless the fossil is wet, crumbly and the substrate is porous and can't be dried before consilidation!
"There is no way to remove this white glue once dried (not even with solvent). It will form a dense polymer layer on the surface without penetrating much into the substrate (white glue are tiny polymer particles dispersed in water with a particle size of around 1µm, so the penetration depth won't be much).
"Butvar, a Polyvinyl butyrate (the company I am working in is also producing these polymers, of course different brand names) in this respect is much better (will penetrate better and can easily be removed by solvents).
"I do have a couple of fossil fish which were mistreated by someone else in such a way. Since the substrate was almost nonporous (diatomaceous earth!) and quite soft (and may be also the amount of white glue and concentration used was too high) there is now a thick slightly yellowish polymer film on top. Unfortunately, this is not all: The film shrinks and now peels off (with bones attached to the polymer film of course)!
Thomas"​

 

[pippinwhitepaws]

never do anything that can not be undone...on museum pieces, fossils, anything that will survive longer than you.

 

[GatorBoy]

I use "Gomer's solution" Ducco and Acetone on all my shell artifacts.
Just as a warning.... if there is any moisture at all in the piece the rapid drying of acetone can quickly destroy the piece...and drying a piece out can lead to its destruction..especially in the sun.
Elmer's..works..its safe..its easy..and it will work on wet or dry pieces... and Harry's dilution rate is WAY off..much too thick!
And I don't have to write a disclaimer to recommended it..haha
You choose.
Also.. butvar will make your piece shiny and unnatural looking.
After that entire quote of one mans opinion.. he still testified that white gkue works.
Lets see that Mammoth tibia Harry.. I bet it looks great.

 

[GatorBoy]

This is what Elmer's looks like after several years.

 

[GatorBoy]

There is no such thing as dry environment in Florida so if you are from Florida and go with Ducco and acetone be sure your piece is dry. It is better than Elmer's but it comes with risks and is not an option on items that may be too unstable to dry out completely without damage.

 

[GatorBoy]

This is what Ducco and acetone did to what was a nice dugong rib that wasn't all the way dry.
Almost the entire surface layer cracked and flaked away.

 

[Perico]

I've never tried to preserve my fossils. I don't have any that look like they are deteriorating. Is it that necessary? Or is It only for fossils that are brittle and unstable?

 

[GatorBoy]

In most cases it's not necessary at all.
And in my experience its mostly the mineralized bone that come from wet environments that required stabilizing so making them bone dry before preserving was way too risky.
I'm sure Harry can load the page full of contradictions to what I just said but that's my experience ... it is what works for me.
I learned the technique and when to apply it from a local archaeologist.
That and I don't keep an infrared light handy... kidding...... no not really. ><>

 

[GatorBoy]

Oh..and if anyone decides to use Duco cement and acetone ..be sure to get the green tube not the blue one.

 

[Harry Pristis]

Museums go to the trouble of consolidating fossils as a long-term investment in preservation. If you decide that it doesn't matter what happens to your fossil bones and teeth after two, ten, or twenty years, don't bother with museum-type consolidation.

Some of your unconsolidated specimens will remain as collected, others will fracture and split. If we could reliably predict which specimens need no consolidation, then we could ignore those to concentrate on the fossils which are at risk. But, we can't make a reliable prediction. (Teeth are notorious for splitting -- after years of stability in a drawer.)

If you DO CARE what happens to your fossils in the long-term, say because

- they are museum-bound as part of your estate, or
- you or your survivors may want the legacy (or the money-value) of your collection, or
- you are a conscientious collector who feels an obligation to curate the objects in your temporary custody,​

then you should make the effort to consolidate all your vertebrate fossils, using museum standards (or as close to them as you can get).

You wouldn't glue a rare stamp into your album, and you wouldn't clean the patina off an old copper coin, and you shouldn't put white glue on your fossil bones and teeth.

 

[Perico]

Thanks guys!