Sealing/preserving fragile ammolite

[jvdlinden]

Hi everyone,

 

I am new to this forum and have been loving it. 

I found a very fragile ammolite preserved in mudstone (I believe) and I want to seal it to preserve it and prevent it from falling apart. What can I use? Can resin/epoxy be used?

[Thomas.Dodson]

Generally a permeable, acetone soluble thermoplastic is used for consolidating and preserving fossils. Butvar B-76 and Paraloid B-72 are two of the most popular ones for fossils. Because these have become more widely available I'd look at getting some, especially if you are going to be collecting more fossils in the future.

 

First, you should make sure the fossil is dry before consolidation. Sometimes I dry fossils at low temp (200F) in the oven but I usually only do this for specimens that tend to hold moisture.

 

A 1:20 Paraloid B-72 to acetone is typical. Suspending the granular Paraloid in something like a tea infuser speeds the process but isn't necessary. Once the solution is mixed up you can soak the fossil in it until the bubbles stop coming from the fossil, and place it on a cardboard flat to dry. You can also brush the stuff on in repeated sessions if the fossil is so fragile it can't even stand a soak in acetone.

[jvdlinden]

Wow, thank you so much! I am hoping to find more fossils in the future.

[Al Dente]

I would test a piece of the matrix in the acetone solution before submerging the fossil in it. A lot of clay, silt, shale and mudstones will disintegrate if put in liquid after they have dried. 

[pachy-pleuro-whatnot-odon]

I personally use a pure acrylic sealant, designed as a craft's sealant, called decoupage medium by Daler Rowney. Gives a bit of a shine, but perfectly consolidates the outer surface of shale without penetrating. It can be brushed on to seal and consolidate the fossil, without risk of it disintegrating (I typically use this stuff on Holzmaden-material) and can be easily scratched off if you decide you want to remove it again (I believe it'll also dissolve in acetone, if needed).