Chonetes bastini prep - thoughts and advice?

[Mainefossils]

This is a recent prep I undertook - a rather incomplete specimen of a Chonetes bastini, a species of brachiopod from the Leighton Formation. I picked this one as a practice piece to try some new techniques on, and was hoping for any tips on different finishes for the matrix. I have heard that beeswax was often used for the matrix to make it appear darker, but did not know the proper methods or appliance techniques. Any thoughts on the finished product are also appreciated!  

 

The specimen itself is missing the upper right left of its shell, and only has two spines present (upper right). Otherwise, it was a well preserved specimen. I applied a thin coating of paraloid to the shell, to make it stand out, as well as preserve it better.

 

The pictures show the specimen before and after preparation. The first image is of it before prep, while the last two are of it after. 

 

Thanks for reading! 

 

@Ludwigia @Terry Dactyll

 

 

 

 

[Ludwigia]

I've mentioned this many times before. The product that I and many other European collectors use is called Rember, a beeswax based finish which is easily removeable with acetone. All you do is paint it on. I'm not sure if it's available in the USA, but similar products must be obtainable there.

[Mainefossils]

36 minutes ago, Ludwigia said:

I've mentioned this many times before. The product that I and many other European collectors use is called Rember, a beeswax based finish which is easily removeable with acetone. All you do is paint it on. I'm not sure if it's available in the USA, but similar products must be obtainable there.

Thanks! I'm sorry, I didn't see the name mentioned in your prep threads - must have overlooked it.  Thanks for your time! 

[Kane]

Lately, I've been using a light sealant/adhesive akin to Loctite, which cures using a UV light. The good thing is there is good control over how much or little "shine" pending how thick or thin you apply it. I find it helpful during the preparation process when I need to stabilize a (cleaned) area before proceeding if the specimen is fragile and liable to fracture from even slight vibration. You can either get the name brand Loctite, or get an off-brand version for cheaper -- either will likely do the job. 

[FossilDAWG]

Is Loctite reversible?

 

Don

[Kane]

4 minutes ago, FossilDAWG said:

Is Loctite reversible?

 

Don

I believe so. The substance is fairly similar to cyanoacrylate, so I think it responds well to acetone (but I would have to double check). 

[tombk]

14 hours ago, Mainefossils said:

I applied a thin coating of paraloid to the shell, to make it stand out

@MainefossilsIt does make the shell stand out, without making it too shiny. What concentration paraloid did you use? 

[Mainefossils]

55 minutes ago, tombk said:

@MainefossilsIt does make the shell stand out, without making it too shiny. What concentration paraloid did you use? 

Thank you! I started with a 2 percent solution, but because of the impermeability of the shale, just applying it resulted in a shiny coat. Instead, I soaked the fossil in acetone first, which penetrates deeper than the Paraloid solution. I read from a paper on the subject (which is cited below), that this usually allows deeper penetration. It also lessens the effect of reverse migration. 

 

Here is the like to the paper: 

Davidson, A., Brown, G. W. (2012) Paraloid B-72: Practical tips for the vertebrate fossil preparator. Collection Forum, 26(2). http://www.connectingtocollections.org/wp-content/uploads/2014/02/Davidson_and_Brown_2012_Paraloid_B-72-_Practical_tips_for_the_vertebrate_fossil_preparator.pdf

 

[Ptychodus04]

I'm a big proponent of using only known conservation grade products on fossils after having been tasked so many times with removing old finishes that were applied. Unless it is 100% reversible for the lifespan of the material, I avoid it.

 

Wetting with acetone does help the paraloid penetrate deeper. Since Paraloid B72 is soluble in ethanol, you can also wet with that carrier to help draw it in and since the ethanol evaporates slower than the acetone, it allows the plastic to penetrate even further.