AluminiumBronze

Project Aluminium Bronze
Can we make aluminium bronze at revspace?
Status	In progress
Contact	Gori, Thomas
Last Update	2018-06-04

Why?

Because we (maybe) can. Also, it is really pretty. For visual comparison of many different alloys, see here. You can find their properties here

Lets make some Aluminium bronze C62500. It properties are here

Composition

• Fe: 3.5 - 5.5 %
• Al : 12.5-13.5 %
• Mn: 0-2 %
• Cu : rest
• Melting point
  • Liquidus - 1051 C
  • Solidus - 1047 C
• Density ar STP : 7.2 g/cm3

Recipes

For 500 cm3 / 3600 g

• Fe : 4% : 144 g
• Al: 13 % : 468 g
• Cu : 83% : 2988

For 400 cm3 / 2880 g

• Fe : 4% : 115 g
• Al: 13 % : 374 g
• Cu : 83% : 2391 g

For 300 cm3 / 2160 g

• Fe : 4% : 86 g
• Al: 13 % : 281 g
• Cu : 83% : 1793 g

For 200 cm3 / 1440 g

• Fe : 4% : 57 g
• Al: 13 % : 187 g
• Cu : 83% : 1196 g

Preparation protocol

Hypothesis

• As we will be using the 500ml graphite crucible for the first time, preheat first to 200 - 300 C, make sure it is stable and dry

Order to actions

1. Load the crucible
   1. Fe, in as fine as possible form in the crucible
   2. Al
   3. Borax
2. Wait for it to melt. We expect Iron to dissolve in molten Al
   1. Stir, check for solid Fe
   2. Add Cu
   3. More borax if needed
3. heat up to 1200 C, max the oven can do. We want to be well above melting temperature, so we have sufficient time to pour before it starts solidifying
4. Pour in stailess steel cupcake forms, to form ingots small enough to fit in the crucible

Experiment 1

10X magnification of one aluminium casting that was poured. Attempt no landings here.

• Used steel wool as soruce of Fe, hoping for fast dissolving in Al. Does not work well.
  • Too large volume, makes packing into crucible difficult
  • Starts burning after while being added to liquid Al
  • Tried wrapping in alu foil, in tight packets. Sort of ok, but very, slow to dissolve, borax get in everywhere , mess.
  • Next time either skip Fe, or try shavings from a file of drilling swarf.
  • With filings, iron will still take a long time to dissolve in Al
• Current crucible handlling tools are inadequate for the oven.
  • All tools must be long enough to never have to reach into the oven, and preferably stick out at least 30 cm from the edge
  • Crucible lifting tongs, that are lockable
  • Long, fine stainless steel tongs for adding metal
  • 2 x Long stainless stirrer / prodder
  • Stainless spoon, with long handle
  • Pouring rings should be custom made for each crucible type, to ensure maximum stability. Make sure handles are easy to pick up then ring lays flat on the table or floor.
• General process observations
  • Set up crucible so that maximum of operations can be done without opening the door
  • A ceramic ring/plate system for stabilizing the crucibles, and reduce risk of tipping over, maybe some form of splash tray.
• Safety
  • As long as you are not reaching into the oven, welding gloves, face shields, leather aprons + flame retardant overalls are ok.
  • Consider getting refactory gloves, sleeves and apron at least, some examples here
• ... more ...