Dr. Ann, Dr. Ann

RSWORD · 17th March 2005, 05:25 PM

Quote:

Originally Posted by Ann Feuerbach

Hi Bill,
Excuse me if this answer is a bit muddled, I have a horrible cold and a fuzzy head

In the future we may be able to carbon date iron, I know Oxford has been working on this with varing amounts of success. Ideally a small uncorroded sample can tell us information such as if there is slag inclusions. The type of slag could in some circumstances suggest a relative date. Elemental analysis can also sometimes suggest whether or not it is new or old iron. We can also tell about the iron/carbon content and heat treatments. Testing rust will only tell you it is iron. Due to segretation and leaching in and out of elements during corrosion, as far as I know you can not get any useful information out of rust. I would be very scptical about any one who says they can learn alot from corrosion. I have found relic structures in corrosion products. It is hard to say what can be learnt about it without seeing it. If you want, send it to me and I can take a look at it and suggest possible aspects for research.
Ann

In regards to using corrosion to date a blade, it might be worth mentioning, that it is the accepted method of dating Japanese blades through the examination of the corrosion on the tang. I think a lot of study as been put into this over the years and one can start seeing trends in the depth of corrosion, color of corrosion, etc. and match this to dated tangs to get an "eye" for dating an unsigned blade. Barring new technology that can somehow date the metal of the blade, studying a blades tang seems to be an accepted method of dating. Thoughts?

Jens Nordlunde · 17th March 2005, 06:27 PM

RSword,
I don’t quite agree with you, although I don’t know much about it, what if the blade had been keep clean and oiled, but the sword itself had been kept in a rather damp place, then the tang would have more corrosion than another sword, also oiled and cleaned, but having been kept in a dry place. Don’t you think?

Jens

Andrew · 17th March 2005, 06:43 PM

I think both Rick and Jens raise interesting and valid points. My suspicion is that tang condition is but one of several elements used to date a Japanese sword. In other words, tang condition, by itself is useful data. Just not definitive.

Comments from Rich on this would be helpful.

Ann Feuerbach · 17th March 2005, 06:44 PM

Perhaps under certain circumstances it may be possible to suggest a date by corrosion, but having spent alot of time with corrosion (during my conservation degree). It would not rely on it. It is so easy to corode something. That said, you can look at the type and depth of corrosion which may suggest if it is genuine or fake, things like intergranular corrosion and what form the iron oxide is in, and if there is any relic stuctures in corrosion products, these factors I believe usually occur during slow corrosion. I have some iron that has been in my garage for only a few years (old file I did not want my mom to toss out, but even in the garage after a short time, they have totally lost their shape. They are even too far gone for me to even attempt to conserve.

Yannis · 17th March 2005, 06:45 PM

Quote:

Originally Posted by Jens Nordlunde

...the sword itself had been kept in a rather damp place...

Jens, in Japanese swords circles this is a blasphemy

Jens Nordlunde · 17th March 2005, 07:28 PM

Yannis, I am sure it is, but some people live near the sea, and som inland - that should give a difference, if maybe only a small one - but over the years?

Jens

Bill · 17th March 2005, 07:41 PM

My original question was in referance to: http://www.tms.org/pubs/journals/JOM...Cook-0305.html , but seems to be less than perfect. I've also read there is some debate to when the "luwa" (Sulawesi) smelting started. Is thermoluminescence viable for these studies or is it just to expensive for Universities for results that still would be questioned.

17th March 2005, 06:27 PM	#2
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	RSword, I don’t quite agree with you, although I don’t know much about it, what if the blade had been keep clean and oiled, but the sword itself had been kept in a rather damp place, then the tang would have more corrosion than another sword, also oiled and cleaned, but having been kept in a dry place. Don’t you think? Jens

17th March 2005, 06:43 PM	#3
Andrew Member Join Date: Nov 2004 Location: USA Posts: 1,725	I think both Rick and Jens raise interesting and valid points. My suspicion is that tang condition is but one of several elements used to date a Japanese sword. In other words, tang condition, by itself is useful data. Just not definitive. Comments from Rich on this would be helpful.

17th March 2005, 06:44 PM	#4
Ann Feuerbach Member Join Date: Feb 2005 Posts: 133	Perhaps under certain circumstances it may be possible to suggest a date by corrosion, but having spent alot of time with corrosion (during my conservation degree). It would not rely on it. It is so easy to corode something. That said, you can look at the type and depth of corrosion which may suggest if it is genuine or fake, things like intergranular corrosion and what form the iron oxide is in, and if there is any relic stuctures in corrosion products, these factors I believe usually occur during slow corrosion. I have some iron that has been in my garage for only a few years (old file I did not want my mom to toss out, but even in the garage after a short time, they have totally lost their shape. They are even too far gone for me to even attempt to conserve.

17th March 2005, 07:28 PM	#6
Jens Nordlunde Member Join Date: Dec 2004 Location: Europe Posts: 2,718	Yannis, I am sure it is, but some people live near the sea, and som inland - that should give a difference, if maybe only a small one - but over the years? Jens

17th March 2005, 07:41 PM	#7
Bill Member Join Date: Feb 2005 Location: Chicago area Posts: 327	My original question was in referance to: http://www.tms.org/pubs/journals/JOM...Cook-0305.html , but seems to be less than perfect. I've also read there is some debate to when the "luwa" (Sulawesi) smelting started. Is thermoluminescence viable for these studies or is it just to expensive for Universities for results that still would be questioned.