Annealling or normalizing in ashes vs vermiculite

Some years ago I published in The Metalsmith, a test I ran cooling a chunk of steel in my ash bucket. Last week I ran a very similar test
using vermiculite instead of the ashes from my coal forge. I was shocked to see that the part cooled much faster in the vermiculite (about 600F in the first hour)than it had in the ashes (about 300F in the first hour). Does anybody here have data that would support or refute this finding? I did find one blacksmith related site where the guy said about the same thing, but his experience was apparently anecdotal.
For what it's worth, either annealing medium will work pretty well for plain carbon steels, and maybe for 4140. But it won't do much for even 01 let alone S7 or other air hardening steels.
I already have the "ashes" test data and graph on blacksmith portion of my website and I will make a page for the vermiculite results if some of you are interested.
Pete Stanaitis
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Pete,
Interesting findings. I thought vermiculite was a better insulator so you would have seen the opposite results. Have you done anything to the ashes, like sifting out small pieces of coke or clinker, or are they whatever got shoveled out of the forge?
Also, on a related note, did you happen to notice any carburizing in the pieces that you tested?
Thanks, Paul
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Hello, Paul.
paul snipped-for-privacy@excite.com wrote:

Exaclty, So did I. Have you done anything to

No. They are mostly the fine stuff that came out the ash dump with a few pieces of clinker.

No, but I didn't check specifically. I did file the part to see if it had annealed at all, which it had. But even if the surface had carburized, the slow cooling would have probably annealed that thin outer layer.
The vermiculite that I used was pretty fine compared to that used by at a recent hammer head making demo I saw. Either way, a handfull of vermiculite seems to have no weight at all compared to ashes.
I am going to look for some coaser vermiculite. Then I will probably rung the test again, with both fine and coarse, making sure my part (about 4 pounds 4 oz of 4140) is well centered in the container and that it has, for sure, been thoroughly soaked at heat.
Pete Stanaitis
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I don't know if you can copy this long crummy url into your browser, but this knife maker talks about the ashes vs vermiculite issue, as do many others.
If the url won't work, I googled "+anneal +ashes +vermiculite" (don't use the quotes) to get there. This site was the first one in the hit list
http://books.google.com/books?id=lrc3sRSR1rEC&pg=PA52&lpg=PA52&dq=%2Banneal++%2Bashes++%2Bvermiculite&source=bl&ots=6jQAfQf-EU&sig=UKlUcfhPWaN82HXAaZlSqcASjfU&hl=en&ei=RRRfS-uXIYW4Nf3_oOcL&sa=X&oi=book_result&ct=result&resnum=1&ved AkQ6AEwAA#v=onepage&q=%2Banneal%20%20%2Bashes%20%20%2Bvermiculite&flse
I still intend to put some more numbers to the anecdotes.
Here's what I have so far:
http://www.spaco.org/Blacksmithing/Anneal/AshBucketAnneal.htm The excel spreadsheet link is toward the bottom of that page.
Pete Stanaitis ---------------
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Sorry about this, but here's a correction, see last line:
spaco wrote:

http://books.google.com/books?id=lrc3sRSR1rEC&pg=PA52&lpg=PA52&dq=%2Banneal++%2Bashes++%2Bvermiculite&source=bl&ots=6jQAfQf-EU&sig=UKlUcfhPWaN82HXAaZlSqcASjfU&hl=en&ei=RRRfS-uXIYW4Nf3_oOcL&sa=X&oi=book_result&ct=result&resnum=1&ved AkQ6AEwAA#v=onepage&q=%2Banneal%20%20%2Bashes%20%20%2Bvermiculite&flse

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Might try baking the vermiculite and not as another test variable. Martin
spaco wrote:

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Let's look at the materials.
1. vermiculite is mica. Mostly Muscovite or the old name Muscovy from the Ural mountains in Russia. It is classified into Phyllosilicates in mineralogy.
2. dry ashes - or mud if water within. Dry is really water driven off and dry.
Therefore when vermiculite is used it is a large array of sheets of mineral and hold lots and lots of moisture. It is hygroscopic as I recall.
The ashes are void of air and moisture keeping scale down and blanket of pre burnt material. It withstands most any temperature until it converts a refined state of minerals.
Likely had steam cooling in the vermiculite.
I've heard of both, and this test you did was good input.
Martin
spaco wrote:

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