Jump to content


Photo

Special Grease Used on Pallasites

  • Please log in to reply
10 replies to this topic

#1 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1294
  • Joined: 08 May 2012

Posted 22 September 2013 - 03:55 PM

Hi:

I just bought 2 pallasites and the shipper said they would be coming with a "special grease" on them to protect them in shipping. This grease can then be removed with alcohol. Does anyone know if using this grease is common for protection and would I just use rubbing alcohol. What type of grease is used?

Thanks, Kent

#2 Lost in Space

Lost in Space

    Vendor - Galactic Rocks

  • *****
  • Vendors
  • Posts: 2085
  • Joined: 14 Nov 2004
  • Loc: North Carolina

Posted 22 September 2013 - 08:22 PM

Kent, which pallasites did you buy? Some can tend to rust more than others, and so you may want to proceed with care.

Rubbing alcohol is usually 70% to about 90% alcohol, the remaining percentage is water. Of course, you might try to obtain pure isopropyl alcohol (same as rubbing alcohol, but no water) and go that route.

I wonder why the seller saw fit to coat them with this "special" grease? Perhaps these are known rusters, and that might be why.

IIRC, Glassthrower has great experience with cutting iron meteorites and perhaps he can share his best practices. I would wait until he chimes in before trying anything.

Ed

#3 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1294
  • Joined: 08 May 2012

Posted 22 September 2013 - 08:27 PM

Thanks Ed. Yes the 2 I bought are known as possible rusters but I thought I would take a chance since I live in AZ, a dry climate and also they were from a very reputable dealer. One is Brahin and the other is Brenham. I also bought a Seymchan. For removing the grease I guess an alcohol with the least water would be best. Perhaps I should ask the seller. I have included pics below.

Brahin

Attached Files



#4 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1294
  • Joined: 08 May 2012

Posted 22 September 2013 - 08:28 PM

Brenham

Attached Files



#5 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1294
  • Joined: 08 May 2012

Posted 22 September 2013 - 08:28 PM

Back of Brenham

Attached Files



#6 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1294
  • Joined: 08 May 2012

Posted 22 September 2013 - 08:29 PM

Seymchan

Attached Files



#7 Dave M

Dave M

    Cosmos

  • *****
  • Moderators
  • Posts: 8262
  • Joined: 03 Aug 2004
  • Loc: Ohio

Posted 22 September 2013 - 08:46 PM

Kent, Those are beauties, makes me want a Brenham or Brahin now.

#8 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1294
  • Joined: 08 May 2012

Posted 22 September 2013 - 08:51 PM

Thanks Dave! Yes I have bought a lot of "stones" in the past 3 weeks and I am winding down. But I saw these and didn't have any nice Pallasites. I knew the 2 were possible rusters and thought I better not get them and got the Seymchan 1st knowing it had a better reputation. But I thought these sure looked nice and were worth the gamble. I don't have them yet but from the pics the Olivine seems to glow without a backlight. I hope they look as good in person.

I emailed the seller to see what alcohol he recommends.

#9 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1294
  • Joined: 08 May 2012

Posted 23 September 2013 - 08:24 AM

I heard back from the seller. He said I could use any alcohol %70-90.

#10 lee14

lee14

    Vostok 1

  • -----
  • Posts: 194
  • Joined: 19 Dec 2009

Posted 23 September 2013 - 09:18 AM

Hi Kent. Those pallasites are certainly beauties. Since the surface has been coated with grease, it's likely they haven't been treated for long term mitigation of rust. They are polished, and not etched, (which is a great look, etching doesn't necessarily add to the attraction), so the grease is there only to protect the polished surface in the short term. It's analogous to purchasing a steel machine tool that has been oiled or otherwise surface coated to keep the surface pristine until use.

The main problem I see with the grease is that's it lacks the penetrating properties needed to keep moisture from the interior. It no doubt does a good job of maintaining the polish, but that's it. Pallasites are no more or less prone to rust than irons in general, but the corrosion can be much more objectionable since it can eventually loosen the olivine from the nickel-iron matrix. Once that level of degradation occurs, it's nearly impossible to reverse.

The good news is that the polished surface is much easier to maintain than one that is etched. If the metal shows fingerprints from handling, or a dulling of the polish, conventional metal polish and a soft cloth can restore the mirror-like appearance. Additionally, I would avoid any alcohol other than anhydrous. There is no need to introduce water into a meteorite, especially a pallasite where it can migrate into the microscopic spaces around the olivine. Also, typical rubbing alcohol can contain glycerine, which while not damaging in itself could inhibit proper drying. The best method of grease or oil removal is acetone, which while it may penetrate into any cracks, will evaporate quickly. If it leaves a dull film behind, simple metal polish and cloth will restore the mirror finish. In any case, a protective metal polish should be used regardless of the method of grease removal.

The other good news is that properly prepared Brahins should remain rust free without any serious precautions. I know these are relatively expensive, so I wouldn't want to encourage experimentation, but I would treat these with gun oil as well. In the case of a polished surface though, it's the penetrating property that is desireable. After allowing sufficient time, I would remove the oil from the surface and apply a metal polish designed for iron or steel. 'Flitz' is one that I've had good sucess with.

Lee

#11 Kent10

Kent10

    Apollo

  • *****
  • Posts: 1294
  • Joined: 08 May 2012

Posted 23 September 2013 - 10:09 AM

All very interesting, Lee. Thanks as always.






Cloudy Nights LLC
Cloudy Nights Sponsor: Astronomics