Tools/castingcrucible/induction

Some of the tools at the Hackspace are potentially hazardous to use, for these tools members are required to have an induction before they can use them. Inductions provide the most basic information on how to safely and effectively use the simpler functions of the tools, we appreciate that some members may have professional experience on some of these tools and in this case please tell your induction provider and the induction may be very reduced and just cover any risks or procedures specific to rLab. Some tools have multiple levels of induction in order to cover more advanced uses of that tool without making the basic induction take too long, higher induction levels will introduce some of the more advanced features of the tools but as with all inductions are only intended to provide basic information on the capabilities of the tools and how to use them safely. Some members of rLab may be willing to offer more detailed tuition beyond basic induction level or offer guided practice sessions in exchange for beer money or assistance on their own projects.

For all tools you are only required to take level-1 induction before use, after that you may perform any task that you feel confident you can do safely, higher levels of induction may be useful to you in performing more advanced operations but are not required before doing tasks covered in them so long as you're confident of your ability to handle those tasks without risk to yourself, others, or the tool.

PLEASE NOTE : All induction providers are volunteers who are providing inductions to the best of their ability but are NOT qualified instructors. Inductions are provided on a best-effort basis but you and you alone are responsible for your safety while using the tools and for satisfying yourself that you can operate the tools safely. There are professional training courses available from various providers in Reading and the surrounding area if you feel they are appropriate for the level of work you intend to undertake. Reading these notes is NOT a substitute for an in-person induction.

Note for wiki editors : Please do not edit induction pages unless you are one of of the people that gives that induction

equipment capabilities

• Types of casting
  • Sand casting
  • Lost-PLA casting
  • Investment (lost-wax) casting
  • Metal mold casting
• We're only going to be doing sand-casting today, procedure for others is under development
• Metals we can work with (Tin/Lead/White-metal, Aluminium, Copper/Brass/Bronze, we can't cast iron/steel)

Object designs

• How the mold is mounted to the boards, creates the cavity which can then be filled with metal, what is cope, drag and board.
• You have to be able to align the 2 parts of the mold using pins
• You have to be able to move the mold from the sand without breaking it too badly, so allow tapers. You can't have overhangs
• Using cores if you need complex shapes but we won't cover that
• Consider how the metal will flow, small cavities are hard to fill, there needs to be a path for metal to get in and gas to get out
• Remember the shrinkage allowance, 2% in aluminium, 1.5% in brass
• What are Sprus, Gates and Risers and why you need each of them
• Design them into the mold, or cut them afterwards once you've made the sand form
• The possibility of designing, 3D printing, Casting and then finishing on the boxford.
• Printing out a mold, carving a mold for wood, high surface finish needed

Making the mold

• Mounting the board to the cope and drag
• The sand is builders sharp-sand and bentonite clay with a small amount of water to make it stick together
• Screening the sand to remove lumps
• Power the mold to help with release
• Packing the sand down hard and completely filling the drag
• First sand layer must be very fine and carefully forced into the smallest of gaps, later layers can be larger and less careful
• Leveling off to enable use of a backing board
• Flipping it over and then repeating on the cope
• Tapping and releasing the mold
• Touching up any defects, large defects mean starting again

Safe clothing

Overalls required - NON-SYNTHETICS ONLY!! Jeans are good Shoes Leather or natural fabric, NO SYNTHETICS, Steelies preferred. - Trainers NOT acceptable MIG Welding gloves should be used, nothing else, no others have sufficient insulation and are non-melting You can get specialized foundry versions of all of this kit, all of which are very effective and very expensive Googles AND face shield when pouring, remember face-mask will burn if there is an accident Dust masks

Beware of concrete spalling in case of spill

[copied over from old wiki]

Due to the temperatures involved, casting is a dangerous process, and the following precautions should be taken before using the furnace.

contents 1 Setting Up The Crucible 2 Pouring Aluminium 3 Cleaning Up 4 Risks and Mitigations setting up the crucible The crucible should be used outside, and should not be used in the rain. There is a steel tray that should be placed outside and then filled with sand. Place the crucible furnace on the tray and then connect it up to the butane, ensuring that all of the pipes and the regulator are fitted tightly and correctly. Once the butane is connected correctly, connect up the mains lead, and turn on the butane. <process for melting ali..... I assume the metal goes in cold?)

pouring aluminium When using the crucible when it's hot, you should use the PPE provided (leather gloves, apron and face mask/shield). Ensure that there are no people crowded around the crucible when you're pouring, and ensure that anyone keeps a safe distance. When you start to pour the aluminium, the flame on the crucible will go out. This is expected behaviour!

cleaning up Pour any remaining aluminium into the ingot mold and let it cool down. Let the crucible cool down as well and unplug it from the mains, and turn off the butane.

Once everything is cool, put the crucible away on the shelf, and then put the sand back into the bin. Put away the tray tidily and sweep any spilt sand up.

risks and mitigations Risk Mitigation Water entering the hot melt Do not cast in the rain Ensure that anyone with drinks are kept well clear of the crucible when in operation Ensure others in the Hackspace are aware when approaching the area Open flame on crucible causing atmospheric dust to ignite Only cast outside Ensure no major dust creating activities are running while the crucible is in operation Hot melt hitting a cold surface (such as concrete) causing the melt to spread erratically, or potentially causing the concrete to explode. Only cast in the sand tray with the crucible on the sand. Ensure the sand is dry before beginning to cast. Fire Ensure all fire exits are clear of any obstructions or trip hazards. Ensure the correct fire extinguisher is available within reach Ensure gas bottles are kept at a safe distance Gas leak Ensure the area is well ventilated Ensure emergency shut offs work and are accessible at all times Check hoses and connections before use Burns from splashes/hot metal/hot equipment wear appropriate PPE (gloves, goggles, aprons) at _all_ times do not approach the crucible without the appropriate PPE Fumes might be given off by lost casting processes or melting aluminium only cast in a well ventilated space Do no inhale fumes Adding cold metal to hot melt can cause the metal to freeze and crack and/or damage the crucible Warm cold metal before adding it to the hot melt pool