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| doubleboost:
Hi Lads More casting video John |
| vtsteam:
So, John was the core still too hard with the change in sand? Or did it turn out okay? |
| awemawson:
For softer cores John, add less Sodium Silicate. 4% by weight at the top end working down as low as 1% for really friable ones. For easier breakdown post casting add icing sugar to the core mix. Years ago when I started using Sodium Silicate I made a series of test cores. I made a 8% mix, made a core, mixed in more sand to reduce the % sodium Silicate, made another core etc each time using digital kitchen scales to accurately assess the %. The ideal does vary with the sand grain size and make up of the sodium silicate (which oddly isn't a specific composition but a ratio) |
| vtsteam:
Awemawson, what was the composition of your sodium silicate then, when you did your tests to arrive at that usable percentage range? |
| awemawson:
The drum is in my remote 'awaiting ROUND TUITS' storage shed - I'll make a note of the composition when I'm next in there. |
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