Can coke be used to prep lyme regis fossils?

[Pterygotus]

Can coke be used to melt away Lyme Regis limestone?

[JohnBrewer]

The liquid coke may well do so being slightly acidic. Why no try acetic acid in the form of vinegar (that’s about 5% acetic acid). I’d try on a test piece of limestone and a poor fossil first tho. 

 

The dry variety of coke, no.  

 

@Ptychodus04

 

[daves64]

43 minutes ago, JohnBrewer said:

The dry variety of coke, no.  

 

The dry variety may make it SEEM to be melting. 

[jpc]

Stay away from the dry version... the economy on Colombia is picking up and we don't need more of a market for the stuff. 

 

But seriously, coke should work but vinegar is cheaper.  And yes, you might be going through a lot of whichever you choose.  There are tricks to acid prep that you should look into before trying it. 

[TqB]

You'd only use acid of any sort on bone from this location. (It can also be used on silicified fossils - e.g. shells, corals - from elsewhere)  As said above, acetic is best and the full process involves washing, drying and coating each bit of fossil as it's exposed to protect it. This may have to be done many times. And maybe using a buffer to control the severity of the reaction.

[Kosmoceras]

Following on from what Tarquin said, you’re not going to want to use acid to prepare your ammonite as it’s composed of calcite which will be attacked by the acid just like the matrix.

[Ptychodus04]

Thanks for the tag @JohnBrewer. 

 

@Pterygotus I would not use coke for the reasons mentioned above. 5% acetic or formic acid is best for acid prepping limestone matrices. You also need to add a calcium phosphate buffer to the acid if you are prepping bone. Otherwise, the acid will attack the bones as well.

 

Any invertebrates preserved in limestone will be dissolved by the acid as well. Acid prep has to be done properly. If done wrong, it is dangerous at the worst, or will ruin your fossil at the best.

[TqB]

Re buffers - the best professional preparator I know recommended a handful of bone meal from the garden centre!