12 replies to this topic

[JimB88]

anyone use vinegar on limestone? whats the best way - to soak it for a time or pour some on wait for an hour or so and remove what it loosened? It a 5% acid..do I need to dilute it further?

[Crinoid Queen]

JimB88, on 07 September 2010 - 10:41 PM, said:

anyone use vinegar on limestone? whats the best way - to soak it for a time or pour some on wait for an hour or so and remove what it loosened? It a 5% acid..do I need to dilute it further?

I have used CLR on lime stone and that worked pritty well. I just put a little one a bruch and scrub it for a tad and then rinse it off real well. I think viniger is for shale but idk?

[tracer]

post a pic of the fossil and elaborate on what you're trying to do. acid is indiscriminate, unless you're dealing with a fossil and matrix of different minerals. you can get away with it a teeny bit on something like removing a bit of carbonate from a calcite urchin test or something, but you have to be careful, and you have to thoroughly neutralize the reaction before you quit the prep. weak acid is still acid - it works by etching and pitting in addition to "cleaning".

[Angus Stydens]

I agree that it depends on what you are trying to clean. Some fossils are more susceptible to becoming damaged than others. I use vinegar all the time to remove limestone matrix from Eocene shark teeth, and it works well on them. The teeth seem to be mostly impermeable to the acid.... but not totally. If I have a shark tooth in a chunk of matrix, I will first use an eye dropper to deposit just a few drops of straight vinegar on the matrix clinging to the shark tooth. I let it sizzle for maybe 20-30 seconds, then eye drop water on it to totally dilute the vinegar. While the matrix is still wet, I use a fine sewing needle to very gently probe into the matrix next to the tooth. You can loosen a little bit at a time this way. I flush the loosened matrix away with more water, then apply the vinegar again and repeat the process until I have the tooth either totally exposed on the block of matrix or removed from the matrix. I also use a small, paint-by-number paint brush dipped in either vinegar or water to very gently brush away loosened matrix. Here is a "before" photo showing a hexanchus agassizi cow shark tooth in matrix as it was found, and the next post will show another after the cleaning (90% finished):

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[Angus Stydens]

Here is an example of another hexanchus agassizi cow shark tooth, 90% cleaned and still in the matrix. Of course, limestone varies a lot in hardness and not all fossils can be removed this way. But it works well in softer types of limestone. After the tooth is completely cleaned and still in matrix, I put a couple of drops of Butvar hardening solution on the tooth to help preserve it.

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[jax]

One thing to remember using Vinegar or other acids. Make sure you wash it all off the piece or it will continue to eat away at the piece. If using on sharks teeth I wouldnt soak them very long as it will start to eat away at the tooth.

I normally use it for cleaning limestone off urchins

[MikeD]

What jax said. Put some baking soda on it, wet it a little and scrub it around with an old toothbrush. Rinse, rinse, rinse. It will neutralize the acid from the vinegar.

[Wakaritai]

MikeD, on 08 September 2010 - 03:11 AM, said:

Put some baking soda on it, wet it a little and scrub it around with an old toothbrush. Rinse, rinse, rinse. It will neutralize the acid from the vinegar.

This. Baking soda is the best and most convenient way of neutralizing acids like this. Rinsing with water does not neutralize acid-- it dissolves it. The acid is still there and still acidic. So, if you don't neutralize it, it will continue to eat. Just mix up a couple teaspoons in a water bottle, shake well, and rinse with the solution. Rinse, and repeat until you don't see any more reaction (and then a couple more times for good measure).

This also works great for cleaning battery terminals. First off, yeah, I know that battery terminals only corrode if they are installed by someone who doesn't know what they're doing... but the fact is, many are. (Because many novices do not know to rub a simple oil coating over terminals and connectors.) Just a few days ago a friend of mine couldn
t start his vehicle because of severely corroded terminals (installed by a "certified" mechanic, no-less). Some baking soda solution, a wire brush, some spare terminals and parts, and a drop of oil later, he's good to go with properly installed terminals. He's lucky that it happened at my place, where we have everything we need. It could have easily happened at a gas station or something, where it would have commanded a hefty tow fee. hmmm... I guess this is as any-- check your terminals Make sure there is no discoloration (green, blue, white, etc) around or on the terminals or connectors. A simple check (to an oft neglected spot) can save you lots later.

[Tony Eaton]

I have read about apatite (i.e. shark teeth and bone) being dissolved by vinegar, but not so much if you buffer the acetic acid first, (i.e. dissolve some limestone first).

The Optimal Acetate Buffered Acetic Acid Technique for Extracting Phosphatic Fossils
Author(s): Lennart Jeppsson, Rikard Anehus, Doris Fredholm
Source: Journal of Paleontology, Vol. 73, No. 5 (Sep., 1999), pp. 964-972
Published by: Paleontological Society
http://www.jstor.org/stable/1306854

[Acryzona]

Here's a link to the full Jeppsson paper that Tony mentioned. I'm trying his method with four different limestone samples (check out my blog on FF) but had to use 5% vinegar because I couldn't find a local source for 10% or stronger. Anyone here know where to get 10% acetic acid cheap?

Edited by Acryzona, 16 September 2010 - 12:39 AM.

[Tony Eaton]

Lowes or Home Depot will often have the 10% vinegar in their organic garden section, but it is $15 a gallon or so as I recall.

[Frank Menser]

I have found white vinager to be very effective for cleaning calcite XLs as well as fossils, but as stated above you need to be very careful about how long things are exposed and then thoroghly rinse. Here's an urchin I used vinager to clean.

[JimB88]

<sigh> I used vinegar to loosen the matrix (limestone) around the third trilo butt Ive found from the Bangor, but I left it in too long and it ate away the actual material leaving only a bad impression of the underside of it... ..fossil hunters..don't..cry

Edited by JimB88, 24 September 2010 - 05:56 PM.