Fossil Preparation

[tracer]

i struggle with fossil preparation concepts. the reason i do is because i care a lot about fossils, and i have read up quite a bit on adhesives and consolidants and micro jackhammers and air abrasives, etc. etc. and, just to be frank, i've seen quite a few fossils that i feel have been ruined by poor preparation. or they are going to be ruined and their owners don't realize it yet. you might ask why should i care, if they're not my fossils? well, i guess i just feel like we're all only temporary owners of our fossils, and they can't be replaced if they're destroyed.

so what are the main problems that lead to damaged or destroyed fossils in preparation/consolidation? well, i feel like they are bad information, too little information, lack of appropriate resources, and impatience. Bad info - your third cousin Billy Ray told you to spray carburetor cleaner on the fossils and stick them in the microwave for lebenty minutes on "stun" setting. sound crazy? not really. i've seen some really bad advice. chemistry isn't a particularly straightforward subject, but it's what you have to deal with if you want to understand why using anything based on cellulose nitrate as a consolidant or adhesive on your fossils is a BAD idea. in a relatively few years that material yellows and shrinks and can tear up a fossil. and it can't be removed because it's crosslinked. yes, lots of us, including me, used adhesives and other products based on cellulose nitrate forty or fifty years ago for various things, but it's because it's what we had back then. nowadays, the only thing stopping people from having the best materials is willingness to part with the money and go through the effort of ordering what isn't available locally. patience is a big deal. yes, we all want that great fossil on display the minute we acquire it. but some fossils take weeks, months or even years to get properly preserved and prepped. i've linked to stuff like the "nautarch" site before to foster insight into just how extensive the serious conservators' methods are. we over time here visit the issues fairly often of how to keep things from deteriorating that we care about. pyritized fossils are a biggie. but less obvious are fossils from marine environments that are loaded with salt that will cause brittleness, flaking, delamination, etc. and then there's the very painful situation many of us have had where we find a very cool fossil in a very unstable condition, and we badly want it to get "fixed" so we can gleefully add it to our collections and oogle it forever (well, the few decades we have, anyway). hey, if you've never gotten to use one of those micro jackhammers, or an air abrasive unit, all i can tell you is that they are magical, wonderful tools, that will astound you if you ever get to use them after doing manual prep. i'm not talking about the time savings, although that's huge. i'm talking about the magic that happens when the fossil emerges from the matrix in ten times better condition than you could have hoped to do it by hand. no wonder some people just have prepping as sort of a full time hobby or love. it's totally cool. ok, ok, i'm shutting up. look, for your trouble in putting up with me, here's a really cool powerpoint presentation on something done very right, in my mind.

cool!

[Rover]

Hey, since you started this topic on fossil prep, I might as well get the ball rolling with a question about a specific specimen. I found some (what I consider to be) very nice corals in the shell layer at Green Mill run, but they're so fragile I don't even dare to clean them with a toothbrush. I'm wondering what I should use to make them a little bit more durable, because that bothers me more than the little bit of dirt still clinging to them.

[tracer]

rover -

you will see the terms "vinac" and "butvar" used quite a bit on this forum and elsewhere when you are reading about fossil prep. if you use the search engine here you can look for those terms. on a more generic note, many "pros" use these things, and they are basically polymer beads, polyvinyl acetate and polyvinyl butyral, and they can be dissolved in acetone, or sometimes in ethanol. very thin solutions can be made or very thick solutions can be made to use as "glue". some mix up "glue" and keep it that way and just thin it with more acetone when they want a penetrating sealer/stabilizer. these polymers do not represent the strongest, most durable bonds/seals possible - that's not the concept. they represent the best of both worlds, in that they are resoluble/removable with the original solvent, and they are also fairly strong and don't tend to crosslink, shrink, etc. if you sort of mess up a brush application, you can clean it off with acetone and re-do it. so anyway, that's my first thought on stabilizing/protecting many fossils. when i believe a fossil is too unstable and is basically a "lost cause" anyway, or need a strong repair of a particular crack, i use cyanoacrylate glue. "super glue" is a very interesting substance. it is very good at wicking into the teeniest crack. i've learned to use the small containers of it. if you get a big bottle and try to use it you will pretty much guarantee that you'll end up getting it where you don't want it, and gluing and burning yourself with it. i put the end of a small bottle flat down on top of a crack, and squeeze just a tiny bit, and as soon as the glue starts coming out, it wicks into the crack. i then remove the bottle and quickly wipe off any glue on the surface. when i do it well, you really can't tell the crack was glued. any "shiny" area can be dulled by wiping with acetone. by the way, moisture is a catalyst for super glue. it works faster/better on a slightly damp fossil. this means you can use it to stabilize a fossil before it completely dries, which sometimes is very important. the end result of using cyanoacrylate is that you've applied an acrylic. it's far less removable/reversible than the first two things i've mentioned, but sometimes it's necessary. i know it is very necessary at times in the field when attempting to remove things from matrix where the fossil is going to explode and you know it. sometimes it's the difference between just taking home a photo and taking home a fossil. anyway, have fun with your prepping and consolidating...

p.s. - i'm not including msds sheets, but be careful and read up on using any chemicals. seriously. you don't want to end up looking like i do.

[Fossildude19]

Great topic. Should be pinned.

Thank you Tracer for making us see the importance of what we hold in stewardship, and the importance of preserving, correctly, the things we seek, and find.

Regards,

Edited July 28, 2010 by Fossildude19

[tracer]

there's just a lot about fossil preservation that isn't all that intuitive. for instance, i was reading recently about how shell fossils can be eroded and damaged by being stored or displayed in cases that are not of archival quality, ie wood-frame display cases or cases with cellulose-based materials that are not acid-free. basically all of my CaCO₃ fossils are in inert plastic storage, except for a few that are out "on display" on shelves with normal indoor air exposure. we've all seen beautiful oak display cases. how many people are aware that those cases put their treasures at risk?

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[pleecan]

This is a good thread ... lots of interesting comments... good one Tracer.

PL