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zinc die cast metal recognition

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  • zinc die cast metal recognition

    I have decided to pursue Gingery's home built machine shop. I am starting with the charcoal foundry. His plan is to first build the green sand molds and practice with pot metal before actually building the foundry.

    He suggests sources of scrap pot metal as being automobile parts. I have reasonable access to automobile parts. My problem, is that I am not sure how to tell the difference between Aluminum parts and pot metal parts.

    Question 1: How can I tell the difference between aluminum parts and pot metal parts?

    Question 2: Are there different pot metal alloys, and are there considerations in melting them together?

    Question 4: Gingery suggest using a portable gas stove for melting pot metal, WOuld a blow torch be as good or better as athe heat source?

    Thank you in advance for helping a nephyte get started in this hobby.

    Geroge Clay

  • #2
    I have been blacksmithing for a few years, the zinc coated stuff is generally some kind of gray in color, darker if oxdized. It may be bright and shiney from the factory.
    DON"T HEAT THIS STUFF UP IN A HOT FORGE OR WITH A TORCH, you will get flashed with the zinc from the galvanizing process. You may never know what hit you. It's nasty stuff.
    Engine parts are generally simple to find out what they are made from, look in the repair guides. Primarily two metals are used in major engine parts, iron(steel) or aluminum. If it's light it aluminum.
    Pot metal can be identified by trying to break a piece with a hammer, if its jagged edged, easy to break pieces off, you have pot metal of one form or another. Pot metal can be many different alloys, too many to specifically identify, because you have all of the offshore stuff that the recipe changes when they get more scrap Pintos in than Hondas.
    I would suggest that you find some aluminum pistons and work from there. If you need other sources, try a lawn mower repair shop, they have lots of neat smaller pieces and parts. They can tell you what they were made from, where a junkyard may not beable to.



    • #3

      I am no expert with pot metal but I can tell you that pot metal is not used for structural parts. From the things that I have seen made of pot metal they are gray in color and not silver like aluminum. Look at things you know are made of pot metal like carbs. Aluminum is used for structural parts and trim parts. The trim parts are usually anodized and have a different look than pot metal. Don't know if this helps or not.

      One thing that you need to be aware of if you are going to do any casting with aluminum. If you pour molten aluminum into water it has the potential of creating a major explosion. It reacts unlike any other molten metal pored into water. There have been explosions in aluminum cast houses that have level the entire facility. Alcoa did extensive test after and explosion in one of there plants. This is just a safety tip for you.

      Good luck with you venture.



      • #4
        Like Joe, I am not pot metal expert. But refeence books give a wide ange of melting points for various pot metals (there are many). All seem to melt below aluminum. Basicaly pot meat is cast, some times plated. It can be welded SOMETIMES. To test for workablity (welding) make some filings and put a torch to them (low pressure so they don't blow away) . So sputter and pop or burn- cant be welded or heat worked. throw it away unless you cast. If it melts and balls up, it can be welded. Use pot metal rod or scrap from the metal as filler.
        If the pot is plated (esp chrome), the plating may not melt while the pot melts and runs out, leaving you a weak shell. throw it away too probably


        • #5
          The high strength Zinc alloys are very strong and make beautiful castings. The AMEN (Alberta Metal Enthusiasts Northern) group in Edmonton uses this alloy with great success.

          You can find alloy suppliers through

          A very good source fo Aluminum is pistons - sheck with a local rebuild shop that deal in desiels and statonary plants. They may not give them to you for free (they do have scrap value), but if you explain what you are doing they may help you out (Donuts help).