Closing in on wheel castings

Thanks to Brian Pate, and to Don Mitchell who suggested I call him, I’ve started vacuuming my castings when I pour them.  Brian indicated that he liked to vacuum before and after pouring, but I’ve found the pre-pour treatment makes little difference.  The post-pour treatment, on the other hand, dislodges all sorts of bubbles from the deep recesses of my molds. The resin is Smooth-Cast … Continue reading Closing in on wheel castings

A good effort at pressure

I’m still grappling with the problem of bubbles in my castings. The accepted wisdom indicates that you want to set polyurethane castings under pressure so the bubbles become very small. I think the Smooth-on site suggests 60 psi (413 Kia). Not having anything that holds pressure, and not wanting to spend a lot of money, I took a trip down to the local Sally Ann … Continue reading A good effort at pressure