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| Green Twin Oscillator Cast/Build |
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| MetalCaster:
Hi David- I try and resized them to 100k or less. More than that and they can get a bit grainly. Thanks for the feedback. |
| ironman:
Mine would sometimes break. Lets hope that yours are successful. |
| MetalCaster:
There is a bit of an art to making sodium silicate cores. I have been experimenting with different percentages of sodium silicate, between 3 and 4 percent by weight of sand. I have a core I made last week, and it is as hard as granite, and then another one that fractures easily. I need to figure out how to get a consistent hardness to the core. Too much sodium silicate and you cannot force the CO2 through it. Too little sodium silicate and the core is too fragile. |
| ironman:
Have you tried using a microwave oven? Gassing them can be hit or miss if they are not gassed properly. |
| MetalCaster:
Nope, I have not tried that. I can't pull the core from the pattern without hitting it with the CO2. |
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