More studies from the home hack sand caster. This time there are no prizes for guessing the object but feel free anyway.
The pattern made from 6 mm MDF and some dowel took 23 minutes in total including several coats of matt paint. Try that with your poncy 3D printers.
The casting came up quite nice with green sand. For this one I used green sand because I thought resin bonded sand with it's higher yield strength might pull the solidifying metal apart as it cooled because of the thin sections (6 mm). Remember aluminium shrinks 7% from a liquid state to solid to ambient temperature. Green sand on the other hand just crumbles quite easily and would offer little resistance to the solidifying aluminium, anyway it worked.
There is however a blemish on my casting record because it took 3 goes before I got it right, I had to add an extra 4 gates and a bigger sprue as can be seen. But for now it's off for final linishing and polishing, stay tuned.
The pattern made from 6 mm MDF and some dowel took 23 minutes in total including several coats of matt paint. Try that with your poncy 3D printers.
The casting came up quite nice with green sand. For this one I used green sand because I thought resin bonded sand with it's higher yield strength might pull the solidifying metal apart as it cooled because of the thin sections (6 mm). Remember aluminium shrinks 7% from a liquid state to solid to ambient temperature. Green sand on the other hand just crumbles quite easily and would offer little resistance to the solidifying aluminium, anyway it worked.
There is however a blemish on my casting record because it took 3 goes before I got it right, I had to add an extra 4 gates and a bigger sprue as can be seen. But for now it's off for final linishing and polishing, stay tuned.