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spider
Dont use it (unless following Freds instructions) is the best thing to remember lol
Have a nice day :0)
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Sharp-eye

Hello, I'm thinking of buying some varnish to protect and preserve some fossils - not all fossils need a coat of varnish. I have a Icthyosaur vertebra which is surrounded/preserved in iron pyrites. I have heard that Iron pyrite fossils should be coated in a clear varnish to protect and preserve them. 


 


Should I get some varnish from here; http://www.kenmannion.co.uk/fossilglues.htm 


 


Or is it best to leave the fossil alone to do it's own thing?


 


The fossil isn't showing signs of rapid decay but I have had other pyrite fossils before which were cleaned but not coated and they have decayed unfortunately. 


 


I see that it has been mentioned here that it isn't perhaps a good idea to seal in a fossil but left to the open air it will decay anyway - so what do you guys reccomend, what have you found works best?


 


Nick Big smile

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gigantopithicus

 It depends on the fossil tbh, each pyritised fossil will lend itself to being treated differently. One of the biggest factors in the decay is the fluctuation of the temperature and humidity, so where you leave the fossils may help the most.

But if you can get some paraloid it does help with some fossils, just make sure the fossil is stable before you seal it.
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ThomasM
Don't varnish pyritic fossils, paraloid is highly recommended but I have heard conflicting reports as to whether it actually keeps the moisture and air out, as being plastic it will be slightly porous. The method which seems to work the most is Fred Clouter's; 10% Ronseal Wet Rot Wood Hardener in Acetone, into which the fossil is then soaked.
Thomas

If you don't look, you won't find.
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Julian123
Nail varnish seems to work well for me - it's a good idea to dry the fossil first in an oven at very low heat.
Julian

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ryanc

Take lots of pictures of it then do your best to preserve it. I don't really think the arguement about 'damaging the scientific value' of a fossil generally applies to pyrite ones.


If it shows any sign's of pyrite rot you need to ammonia treat it first before coating it with anything.

 

Good luck!

 

Regards,

 

Ryan
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ThomasM
I'm not sure I completely agree Ryan - although I agree it is best to preserve the fossil as well as you can there is no argument for using a bad, unreversible method that ultimately obscures surface detail and diminishes the scientific value, like the many pyritic fossils I have seen in old collections that are covered in a layer of horrible high gloss varnish that is peeling off. It is best to use a reversible method, because in the end any coating you put on it will eventaually fail and let water vapour in. The best treatment available at the moment is to put the fossil in a sealed container with silica gel to lower the humidity.
Thomas

If you don't look, you won't find.
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ryanc
ThomasM wrote:
I'm not sure I completely agree Ryan - although I agree it is best to preserve the fossil as well as you can there is no argument for using a bad, unreversible method that ultimately obscures surface detail and diminishes the scientific value, like the many pyritic fossils I have seen in old collections that are covered in a layer of horrible high gloss varnish that is peeling off.


 

Well I didn't reccomend a coating but in my opinion the scientific value of a pile of dust is zero.

 

I wouldn't reccomend non-reversible coatings in general on non-pyrite fossils but I dont think there is a reversible coating that creates a decent moisture barrier in the long term.

 

If it was a fossil that had high scientific value I would store it in an non-oxygen environment - I believe synthetic mineral oils have been used in the past but clearly this is not practical for a whole collection.

 

Additionally, I dont think the Ronseal method you reccomended is a truly reversible one but you can de-shine it with acetone and it certainly does a good job of preserving pyrite.

 

Regards,

 

Ryan
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ThomasM
I agree Ryan, I just wanted to make sure nobody would coat an important specimen in something horrible.
Thomas

If you don't look, you won't find.
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Sharp-eye

Thanks guys, has anyone checked the link I included? - what do you think of that varnish, - I have read that it is not a good idea to varnich bone but the fossil that this is about is a vertebra which isn't preserved in pyrite but rather surounded by pyrite - the bon itself isn't pyrite but it is amoungst pyrite. - Therefor I was thinking of just coating the pyrite areas. - What do you think about that?


Nick Big smile
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Julian123
The varnish in your link looks ok to me.
Julian

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Fred
Clean the fossil thoroughly then dry off in an oven at low temperature to dry it completely.
The best thing that you can do is immerse the fossil in a weak solution of Paraloid B72. About a 15% solution should be effective. Use acetone to thin the solution, or to place the crystals in. The paraloid will then coat the pyrite at a molecular level which will help to slow down any decay.

Pyrite decay is inevitable. You can only slow it down however some forms are more stable than others so longevity of the specimen will vary depending upon type. Check out the PDF page on my website for more information.

Fred

Fred
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spider
and obviously varnish comes in silk and matt if you dont want to achieve that glossy finish Wink
Have a nice day :0)
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Sharp-eye
Cool thanks everyone, I hadn't realised varnish for fossils was such a complicated thing lol.
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