Log in or Sign up
Coin Talk
Home
Forums
>
Coin Forums
>
Bullion Investing
>
Home Made Silver Bar
>
Reply to Thread
Message:
<p>[QUOTE="desertgem, post: 1651203, member: 15199"]There is a physical property known as Specific heat or specific heat capacity. It is the amount of heat required to raise a mass ( usually 1 gram) 1degree C. ). A high specific heat means it takes more heat to raise the temp. and once the heat is removed longer to cool down. The reverse with low specific heat substances such as metals. Water has a specific heat of 1.000, copper is 0.386, silver is 0.223. Raise water 50 deg.C (say from room temperature ) takes more heat than raising same amount of copper, but when the heat is removed, the copper cools much faster than the water. This is the problem most are ignoring. Your melting has to require a high enough temperature for a long enough time, WITHOUT allowing the heat to escape from the mass. With a torch, the heat is hitting a small area. Easier to melt 10 grams of copper with a torch, but to heat 4 ounces, or 16 ounces, the heat has to be affecting the whole mass, not just part at a time. It will soon be losing heat as fast as it gains it, and the temp. won't increase. </p><p><br /></p><p>To melt large amounts, you need large even heat source or an insulating environment such as a kiln.. Torch temperature is not the problem, heat capacity is the problem. I have seen homemade kilns made from fire bricks and 2 or 3 natural gas powered 'weedburner torch heads' reach the needed temperature and hold it long enough for the whole mass to liquify evenly and then slowly cooled down. If you know some one who does ceramics, they may have a kiln that could do it. A flux is also used to promote even melting/cooling. A person who taught ceramics hand built a small firebrick kiln about 18 " on a side and used one weedburner and a BBQ propane tank to melt various metals for sculpture/jewelry. The inside was about 8"x8x8". The insulation was what allowed it to work. IMO. Burn or blow yourself up at your own instigation.</p><p><br /></p><p><br /></p><p><br /></p><p><br /></p><p><a href="http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/inteng.html#c4" target="_blank" class="externalLink ProxyLink" data-proxy-href="http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/inteng.html#c4" rel="nofollow">http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/inteng.html#c4</a>[/QUOTE]</p><p><br /></p>
[QUOTE="desertgem, post: 1651203, member: 15199"]There is a physical property known as Specific heat or specific heat capacity. It is the amount of heat required to raise a mass ( usually 1 gram) 1degree C. ). A high specific heat means it takes more heat to raise the temp. and once the heat is removed longer to cool down. The reverse with low specific heat substances such as metals. Water has a specific heat of 1.000, copper is 0.386, silver is 0.223. Raise water 50 deg.C (say from room temperature ) takes more heat than raising same amount of copper, but when the heat is removed, the copper cools much faster than the water. This is the problem most are ignoring. Your melting has to require a high enough temperature for a long enough time, WITHOUT allowing the heat to escape from the mass. With a torch, the heat is hitting a small area. Easier to melt 10 grams of copper with a torch, but to heat 4 ounces, or 16 ounces, the heat has to be affecting the whole mass, not just part at a time. It will soon be losing heat as fast as it gains it, and the temp. won't increase. To melt large amounts, you need large even heat source or an insulating environment such as a kiln.. Torch temperature is not the problem, heat capacity is the problem. I have seen homemade kilns made from fire bricks and 2 or 3 natural gas powered 'weedburner torch heads' reach the needed temperature and hold it long enough for the whole mass to liquify evenly and then slowly cooled down. If you know some one who does ceramics, they may have a kiln that could do it. A flux is also used to promote even melting/cooling. A person who taught ceramics hand built a small firebrick kiln about 18 " on a side and used one weedburner and a BBQ propane tank to melt various metals for sculpture/jewelry. The inside was about 8"x8x8". The insulation was what allowed it to work. IMO. Burn or blow yourself up at your own instigation. [URL]http://hyperphysics.phy-astr.gsu.edu/hbase/thermo/inteng.html#c4[/URL][/QUOTE]
Your name or email address:
Do you already have an account?
No, create an account now.
Yes, my password is:
Forgot your password?
Stay logged in
Coin Talk
Home
Forums
>
Coin Forums
>
Bullion Investing
>
Home Made Silver Bar
>
Home
Home
Quick Links
Search Forums
Recent Activity
Recent Posts
Forums
Forums
Quick Links
Search Forums
Recent Posts
Competitions
Competitions
Quick Links
Competition Index
Rules, Terms & Conditions
Gallery
Gallery
Quick Links
Search Media
New Media
Showcase
Showcase
Quick Links
Search Items
Most Active Members
New Items
Directory
Directory
Quick Links
Directory Home
New Listings
Members
Members
Quick Links
Notable Members
Current Visitors
Recent Activity
New Profile Posts
Sponsors
Menu
Search
Search titles only
Posted by Member:
Separate names with a comma.
Newer Than:
Search this thread only
Search this forum only
Display results as threads
Useful Searches
Recent Posts
More...