Difference between revisions of "Aluminum Recycling"

Latest revision as of 18:09, 23 June 2010

Using old soda cans

• Collect your cans, the more the better

• Cut the tops and bottoms off. For instance use shears or scissors. You want to seperate the cans into 3 sections. The tops, sides, and bottoms. The side when cut, looks like a thin single sheet.

• Drop them all into boiling water and boil for a few minutes. This helps by cleaning and removing any varnish and soda left in the can. It also helps by removing/washing any sand/dust that tends to collect in a can left laying around or "donated". Let air dry.

• The bottoms have the most metal and can be stacked one on top of each other. Like the fake potato chips that come in a can.

This reduces the surface area quite a bit. When it begins to melt, the bottom forms a pool that gravity pulls the stack into the melt pool. Your dross will be minimal. I have used no flux, borax, wood ash, charcoal ash, pure carbon from a oxy/acety torch, etc as covers.

• When I started I made my own flux from Borax brand melted in a crucible till it goes 'glassy' and then crushing it. It was easier to

buy some from a supplier later.

• Now take a washed side and roll it into a tight cylinder, then add another, etc until you have a nice thick solid roll of sides and tie off with aluminum wire to keep it together. Add that to the melt.

• I don't usually bother with the tops, other than submerging them one at a time until they melt. It's usually too time consuming.

• Nice clean skin with very little dross and I get about 75-80 percent conversion into ingots.

• I use old quart cast iron pots as crucibles. The one with lids can be drilled to make pouring easy, and they skim the pour very nicely.

• Just before pouring I stick in a steel rod and stir it a bit. This helps to get rid of any bubbles.

If you can't afford or find better materials, like old engine blocks or other parts, aluminum cans are worth using. Do add some zinc or copper or both, and do flux the melts to get the most aluminum for your fuel that you can.

Purity of aluminum in cans

Aluminum needs to be almost pure ( read that as close enough to pure as to not matter ), in order to be drawn ( stamped ) in to such thin sections without becoming brittle in the process.

What is in the can?

Have you cheched on the cans for recycling marks, In Europe they took over the german system of marking the cans with a triangle made out of arrows with in the center either a number or Alu inside the triangle.

Using old Aluminum wheels

Wheelium is often Al-357(?), which is excellent for casting stress parts and machines well.

HOWEVER, some wheels contain Mg in their alloy and that presents problems of explosion, flammability and reaction with a steel crucible. You must test the wheel alloy....BEFORE... you try to melt it in the furnace.

Checking for magnesium #1

Take a little chunk of the alloy and torch it with a hand-held propane torch. Look for brilliant white flame / sparks. If, present, there's Mg present, so find another source.

Checking for magnesium #2

I find the easiest sure method is to scrape off some filings or small chips, - if it melts with a propane torch then its aluminum if it flares its probably mg or alloy with mg.

Checking for magnesium #3

Put a drop of muriatic acid on the item in question, if it bubbles freely, it is supposed to have magnesium in it

Using old alu pistons

Pistons are a very good source of aluminum for castings! The cleaner the scrap the less trouble you have during the melt, and the less wasted dross. You can clean the gunk off with soap and water but then you have contaminated water, so it might be best to melt what you have into ingot trays and pit the dross in the garbage, then recast the ingots into final castings.

Used printing plates

A great aluminium source if you can get it is used printing plates. Smaller printers often put them in the trash.

ZA-27

27% Aluminum, 2.2% Copper, 0.015% Magnesium, and 71% Zinc. 0.181 lb/in³, melts at 709-903°F secret recipie:

• $1.99 in post-1982 pennies
• 1¢ pre-1982 penny
• 13 beer cans

Misc

Wheels are a great source and are probably in most cases 356A alloy, great for casting and machining. Cans are also good when zinc and copper are added to make ZA-? alloys.
Some see recycle as something lower on their list of 'to-do's' but any form of aluminum can be melted and made useful with just a bit of study and adding the correct materials! Wheels can be broken into smaller pieces suitable for the crucible by a methos of 'hot short' which means roasting over a fire until at the stage of crumbly like a fresh cookie