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 600°F in the first hour)than it had in the ashes (about 300°F 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
Reply to
spaco
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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
Reply to
paul_bilodeau1
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
Reply to
spaco
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
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I still intend to put some more numbers to the anecdotes.
Here's what I have so far:
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excel spreadsheet link is toward the bottom of that page.
Pete Stanaitis ---------------
Reply to
spaco
Sorry about this, but here's a correction, see last line:
spaco wrote:
formatting link
vermiculite test*** is toward the bottom of that page.
Reply to
spaco
Let's look at the materials.
1. vermiculite is mica. Mostly Muscovite or the old name Muscovy from th= e Ural=20 mountains in Russia. It is classified into Phyllosilicates in mineralogy= =2E
2. dry ashes - or mud if water within. Dry is really water driven off an= d dry.
Therefore when vermiculite is used it is a large array of sheets of miner= al 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 r= efined 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:
Reply to
Martin H. Eastburn
Might try baking the vermiculite and not as another test variable. Martin
spaco wrote:
Reply to
Martin H. Eastburn

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