Tatara

[BIG]

All about...

 

http://www.hitachi-metals.co.jp/e/tatara/nnp0109.htm

 

Best Regards

[SAS]

Very nice article, Shimane province has excellent iron sands and is a famous tamahagane producing area. The article does state that flux is not used during the welding of the tamahagane while forging; this is not strictly accurate, as the  burnt rice straw used has silica in it and the rice paper and runny clay blocks oxygen and acts as flux.

[ROKUJURO]

Steve,

while the forging/welding temperature is about 1.200°C, the melting point of silica is 1.713°C, and rice straw ash contains about 90% of it. I think it must be mainly the clay which works as a kind of flux. 

[SAS]

Jean, you may be right, however, the old timey blacksmiths in the western tradition used silica sand as flux, primarily to reduce scaling and loss of material. It would seem the Japanese smiths used the materials available locally to do the same, as well as wet forging to pop off remaining scale residue.

[Ken-Hawaii]

Jean, rice straw ash contains 75% SiO₂ according to a Chinese study. That actually surprised the heck out of me, as I thought it was more in the 15-20% range, & that ancient tosho used it for its carbon content. Interesting!

 

Ken

 

 

 

[ROKUJURO]

Ken,

ashes are the mineral residue of (in this case) plants, and as grasses (GRAMINEAE) contain high amounts of silica which gives them their incredible strength (bamboo is a 'grass'), a completely oxidized rice hull ash (water free) can indeed contain very high amounts of SiO2. I have worked with this material.

Rice straw ash can contain small amounts of carbon if not burnt properly.

Rice hull ash (mostly coming from China, but Japan has its own production) is used in large amounts and widely in the iron producing industry as an insulating material to cover the melted iron in an open crucible. It just floats on top of the iron.    

[Jean]

Perhaps already posted but one of my prefered video:

https://m.youtube.com/watch?v=-t-oZ6X1sho

[Greg F]

Always a pleasure to rewatch this great video that features our fellow member Mr Bottomley, thanks Jean. Cheers.

 

Greg