aNtistic design

Step 9 Something smelts funny

WARNING--- Although zinc can be handled in its solid form without risk of poisoning .zinc fumes are toxic and of coarse should not be inhaled (sit up wind of the fumes or have a fan blowing from behind you) .not to mention in the molten state at 786F and aluminum melting at 1218F .proper safety gear such as face shield, leather work gloves under welding gloves, welding leathers, leather shoes and long cotton jeans should all be worn ---END WARNING

Now that safety is out of the way .its time to make an alloy .the simple definition of an alloy is a substance that is a mixture of two or more metals, or of a metal with a nonmetallic material .in this instance my alloy would be zinc aluminum know as a ZA alloy .ZA alloys were designed for gravity casting (which is the type of casting I'll be doing) .although unsure of the exact percentages of zinc to aluminum my guess would be it was about ZA4 or ZA12 which means 4% or 12% aluminum .when making an alloy with one metals melting point being 432F higher then the other .it will bring down the melting point of the aluminum and raise the melting point of the zinc

The sand excavated by the ants and placed on top was just sitting loosely .the slightest disturbance of the form could cause sand to rush back into the tunnels .I noticed that even the ants walking on the sand could be enough to cause a cascade to start .my initial plan was to remove the sand with a scoop I made from an old spoon .but that turned out to be problematic .not only did I cause sand to tumble back down the tunnels it also flattened the surface making it unsuitable for the ZA to properly flow .so my next option was to use a shop vac and a crevasse tool .I drilled holes in the top of the crevasse tool to limit the amount of suction at the tip .which also allowed for fine tuning by simple placing a thumb over the drilled holes

To ensure I had enough metal to cast all of the ants tunnels .I poured the sand I had vacuumed(down till I saw the red line) off the top into the crucible and that told me how much ZA was needed .when I melted my zinc I was just shy of the amount needed .when I added the aluminum I reached the required amount .I also found out something interesting .that was that ,if you have molten zinc .and a solid hunk of aluminum .the aluminum will float on top of the zinc .it makes sense now since zinc is much more dense then aluminum but it was something I'd just never though about outside of this situation

I built a small floor and two partial walls out of fire brick to help hold in and reflect the heat (and to keep from burning anything down) .making sure to leave room for the tongs to be able to fit around the crucible .I should have melted my aluminum first since it has the higher melting point but I was able to melt the aluminum after the zinc without any issues .once my alloy was melted and thoroughly mixed (stirred with a spare piece of rebar) it was time to pour .I made sure I had all obstructions away from the area I was to be walking to get to the form and from all around the form .you need to make sure you pour quickly but in thin streams so you don't overwhelm the tunnels causing collapse or clogs .sadly I had no way of taking pictures of myself pouring the ZA since my hands and focus were elsewhere

Comments

[robbtoberfest]

Melting metal is awesome!!!!!!!!!!!!!!!!!!!!