Originally Posted by
Pete O
Hi Vin, I was hoping someone with far more experience than me might reply to your post but having been doing some limited research in preparation for a little bit of yellow metal casting, it seems likely that the porosity is due to an oxidising condition in the melting process, i.e. a lean burn, resulting in gas absorption into the molten metal that is then released after pouring. Did you de-oxidise the molten metal before pouring?
It would be great if you could post a thread describing how you did the swept molds, even if you used the same photos as your link but with some description attached.