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Here is a method of making a match plate for sand casting using an existing patern. I first saw this used to make copies of door knockers. You will need two flasks. One for actually making the item and a larger one that will be big enough to cast a match plate for the smaller flask. This is most useful for copying items or eliminating labor when there is a complicated parting line.
The process is broken down into these steps:
- Using the larger flask, ram your patern in the cope or drag, whichever is most convienient.
- Cope out the patern to the parting line.
- Ram the drag or cope.
- Cut sprues and runners as you would for a normal casting.
- Add strips or a ring to create the void that will be the cavity for the plate.
- Close and pour.
- Finish the match plate by adding pin holes and removing sprues and risers.
Here is the barrel, core and the two combined for a casting for the barrel of a reproduction antique fire cracker cannon.
This will be the example used here.
Here you can see the rather complex parting line.
The barrel is cast upside down so imperfections will float to up to the bottom surfaces.
Here is the barrel and core in the drag all coped out and the sand without the paterns.
Here is what the cope sand looks like.
Here is the cope and drag with sprue and runners cut just as if you were to cast the cannon barrel (without the core!).
All we have to do now is create the void that will become the match plate itself.
Strips of wood or metal of uniform thickness (3/8" thick is about right) are laid around the edge of the drag.
Pack some sand against the strips to protect them from the hot metal.
Close the mold, clamp, weight and pour. Zinc or aluminum is a good choice for this job.
The view on the right is a section of the closed mold. All the patern details are separated by the thickness of the strips which also determine the thickness of the plate.
Cope Side - Here is the resulting casting. - Drag Side
Here is the casting cleaned up and ready for use.
Here is the actual patern and and resultant match plate.
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