Quote:
Originally posted by Since87
According to this list of thermal conductivities hard drawn copper (which is preferable to use for machining) has only 89.5% of the thermal conductivity of annealed copper.
Anyone know enough about this stuff to suggest a good home annealing technique?
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An annealed material has better thermal conductivity than that of a cold worked material because it has larger grains which transmit heat better than the smaller grains found in a cold worked (in this case hard drawn) material.
The are many variables that affect what temperature a material should be annealed at, but it is typically between 1/3 and 1/2 of its melting temp (pure copper's Tm is 1083 C). So to anneal a block of copper (assuming its relatively close to pure) youre going to have to heat it in the range from 360 C to 540 C. A torch should work assuming it burns that hot (I'm not too familiar with torches or welding). I'll speak with one of my professors today who may be able to recommend a better way to "home-anneal" a block of copper.