| The Shop > Metal Stuff |
| risers on iron castings |
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| ironman:
For this video I had a helper come around to film the birds eye view when pouring. It is so everything I can see you will see. You mentioned that my sand looks wet, it has the standard 4% moisture. You probably noticed I don't use a vent wire and still get blowhole free castings. Sand has to have enough porosity to prevent that. Have a look at my video where the casting is knocked out, you will notice the sand is very wet where the cast iron weight prevents the steam from escaping to the air. When I see that I know that the sand has enough porosity. About 23 years ago I toured through the Cat engine foundry in Peoria Ill. They used a large machine to compact the engine block molds. I saw no vent wires being used. The molds were closed and went to the pouring station. The tour guide told me that the sand moisture content was strictly controlled to prevent defects. |
| vtsteam:
MIne tested to 2.5% moisture, so I think I can try to come up a percentage point with it and see what happens. |
| Meldonmech:
Hi What is the black facing sand you use? Has it a plumbago content? Cheers David |
| ironman:
The sand is black because coal dust has been added. |
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