How to care for your iron and pallasite meteorites.
CARE AND FEEDING OF IRON AND PALLASITE METEORITES
In order to keep your iron meteorites in good shape and rust free, you will need to do a little maintenance. With the proper care I believe even sliced and etched iron meteorites with names like Campo del Cielo and Nantan, will last as long — or longer — than you and me.
The main enemy of our iron meteorites is moisture. It can be in your display case or already deep inside your favorite specimen. In order to keep moisture out I use and recommend a small dehumidifier unit in each display case. Mine is called a "Renewable mini-Dehumidifier." When it gets too much moister in its pellets it turns a pink color. All I have to do is take it to an area where moisture is not a problem and plug it in. The unit warms up and releases the moisture into the air and is soon ready to dry your display cases again. The manufacturer says this unit will last 10 years and they only cost about $20 each.
Now that the environment is as dry as we can make it, most irons and slices will remain rust free as long as we follow a few simple procedures. You need to pick up each slice or end cut and inspect it at least once a month. This should not be a really big chore as most of us really enjoy looking at them, that is after all why we have them in the first place, right?
What we are looking for is any spot that is discolored — maybe not yet actual rust but a little brown or yellow. These spots will usually start around the edges and in tiny little fractures in the meteorite. A bright light will help you spot any problems and yes you had better wear your glasses. If you find any of these spots you will need to get some CLR. That stands for Calcium, Lime, and Rust remover. You can get it at any store that sells cleaning supplies. For small spots I just dip a Q-tip in the CLR and gently rub the discolored area until it is bright shiny metal again. Some spots wipe right off while others need to be wet and then after a few seconds rubbed and repeated for several minutes until the tough spots have disappeared. After they are clean they need to be rinsed off with alcohol. I use a plastic container with a lid. I use the alcohol with the least amount of water that I can find. Of course 100% pure is the best but if you can get 91% alcohol during your normal shopping. I pour enough it the container to throughly wet the piece I am cleaning and use a plastic brissle brush to gently rinse all the CLR off the piece. Then when I am finished I pour the alcohol over the piece in a final rinse. This is only nesecery when I use a lot of CLR on a piece. If I just used a Q-tip on a small area I just use the other end of the Q-tip to rinse the area off with alcohol. Once the piece is rinsed off with alcohol the piece needs to be re oiled.
I use and recommend Automatic Transmission Fluid (ATF). Yes the red stuff you put in your car's transmission. In the case such as the one we just described, I like to lay the slice in a plastic container and entirely submerge it in the ATF for a few seconds and then wipe off the excess with a clean soft white rag. Just in case you did not already know this, the etched surface of iron meteorites will scratch very easily if they are rubbed with something abrasive or sharp like another iron meteorite slice.
Following this treatment, the slice is ready to go back on display. Depending on how often you find little spots, I recommend letting the slice soak overnight, completely submerged in the ATF, about every month or two. If you have to clean spots with the CLR every two weeks you might want to soak them more often than that. If you have a slice that is a constant problem or noticeably worse than the others. I recommend putting it on a small plate so it won't get scratched and put it in the oven at about 200 degrees for one hour. This will drive out any moisture in the cracks or inclusions. For a pallasite do not use that much heat, stam in the warm range or 150 degrees.
While the piece is still hot drop it into ATF or a good quality light oil, once it is cool it is ready to dry off and put it back on display.
When you handle a slice try not to touch the bare metal with your hands. You will get oils from your skin on the metal surface. Always hold a slice by the edges.
A complete iron sometimes will start to rust on the outside. If the iron has been cleaned and has a dark grey or black surface you can use the same basic procedure as we described for slices. For an individual iron meteorite with a rusting problem I first recommend putting it in the oven to drive off any moisture that is inside. As a rule of thumb, leave the iron in the oven for one hour for each pound of meteorite. In other words, the bigger the iron the longer you want to leave it in there. I use a low temperature of 200 degrees, but they will still take some time to cool off after you turn off the oven.
If you wrap your meteorites in a paper towel this will keep them dry as they cool off. Once the iron is cool enough to handle, submerge it is the ATF overnight.
For a smooth round specimen you can just wipe it off and put it back into the display case. If it has thumbprints and a lot of character, I like to let it sit on a rag or some paper towels. I pick it up and wipe it down every once in a while. This might take a day or two, so just leave it in a place where you can see it. After a while it will quit dripping and will lose that wet shiny look. When it looks right then it is ready to go back on display.
If you have an iron with a natural patina, rusting is usually not an issue. But sometimes we have and end cut on an iron with a natural patina. In this case the ATF will change the patina in an undesirable way. It will always look wet, and the natural look will be lost. You can sometimes restore the natural look by using Dawn dish soap and distilled water to wash the oil off. Use a lot of soap and a tooth brush to get into all the nooks and cranies.
Once you have done this, the piece needs to be dried in the oven as described before. But once it is dry it will still need some oil on the metal face. I like to use a plastic container. Then I dampen a paper towel in ATF, not soaking wet, just damp. The only way I know to do this is to squeeze out the paper towel with your hands. You can, of course, use a rubber glove to avoid contact with the ATF.
Then I lay the damp paper towel in the bottom of the tray. I like to use a double layer of paper towel. Then I gently lay the etched face on the damp paper towel. This way the face is exposed to the oil but it does not soak the patina. I would leave it overnight and then wipe it off and return it to my display.
I would like to offer my help if you have any problems with your slices that need to be repaired. Just let me know what you have and in many cases I can repair them at no charge as long as they were purchased from me. Even if you bought them somewhere else I can fix them at a very reasonable cost.