RE: [meteorite-list] Re: rust and crust
Stephen, I have also treated Irons with NaOH , it is important to wash them well in good quality 'distilled' water, and alcohol (preferably anhydrous pure) and dry in a drying oven for a few hours, then quickly apply a coating of VCI/metal protector [before the iron cools] (otherwise moisture condenses back onto the surface, when it gets cold). You should handle irons with gloves until they are protected, otherwise fingerprints start the rust cycle off. One of my other Hobbies is Clock repair, and we often have similar problems with watch/clock movements, you find that once you clean a metal surface such as a watch movement, it is far more likely to tarnish than before! So you need to get some sort of barrier onto the surface to prevent condensation corrosion, most clock cleaning solutions have a VCI added for this very purpose, you can also wipe with oil, (although some oils contain water!!) or lacquer of course as a last resort. I suspect that the use of a 'clock cleaner solution' (Non-Ammonia based!!) or 'clock rinse' with VCI added, could be a good thing to use as a cleaner to remove rust, as people have been putting a lot of research into corrosion prevention in this area with good results, and there are numerous concoctions out there to prevent rust. I don't know if anyone has ever done any serious research into corrosion prevention in meteorites, maybe we should bite the bullet and start a large scale trial, to see just what works an what doesn't? Just my thoughts, Mark Ford __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
Re: [meteorite-list] Re: rust and crust
--- Stephen McMann [EMAIL PROTECTED] wrote: - Dear List, I thought that I would ask a question relating to the never-ending rust thread. I hope that this has not already been fully addressed. As a fairly new collector I may not be familiar enough with the archieves. Those who are tired of rust discussions should not read this. A large part of my collection consists of Sikhote individuals. Of course one of the many things that makes Sikhotes appealing is that they are usually relatively stable. This combined with their abundence makes it tempting to treat them carelessly. However, I wish to err on the side of caution. I want mine to be in good condition many years from now. I have taken measures to inhibit the arrival of fresh Cl- and moisture. They currently live in plexiglass cubes with VCI paper and silica dessicant. Several were wiped with a silicone gun cloth. However, I aquired my SAs from a variety of sources and can say little about their histories. I am sure that at least some of them have been held in sweaty hands. One of them (a fairly well oriented individual) is shedding flakes, suggesting that it is sick. Of course another characteristic of SAs is that individuals are covered with a delicate crust whose characteristics have been determined by some combination of rapid passage through the atmosphere, post-fall weathering in the field, and post-collection treatment. Some crusts are black, rich in magnetite, and often smooth or marked with flow lines. Other crusts are more orange, rich in limonite, and can be avariety of textures. I'll say that both kinds of crusts can be interesting and attractive. On the other hand I don't want a meteorite with a touch of orange to turn into a ball of poo. I have been intrigued by recent discussions about stabilization treatments such as soaking meteorites in alcohol and perhaps adding some NaOH to help remove CL-. Now the question. Can anyone tell me what treatments are best for stabilizing crusted meteorites? In particular, how will NaOH affect the various kinds of crusts that you can find on SAs? Thank You Stephen McMann In my experience with NaOH, with distilled water and alcohol, rusting does not occur and only the offending chlorides are affected and neutralized. Mix according to the stated method, and if you find that there is a layer of brine at the bottom of the container, add small amounts of distilled water till it goes back into solution. I have use NaOh with SA's several times and each came out with good results. Steve Schoner/ams __ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com __ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
