I'm wondering what people use as 'washes' to fill in the gaps in the sand of cores and moulds, in cases where a fine finish is needed, or to prevent sand 'burning on' to the surface of the casting. Any suggestions?
In post 4 you posted photos of straight edges with a large amount of flash around the parting line. That should not happen with bound sand because when I use it there is no flash around the parting line.The only cleanup necessarily is using a paintbrush to finish wiping off a slight amount of sand.
These castings do not require any post-casting cleanup or wirebrushing.
In post 4 you posted photos of straight edges with a large amount of flash around the parting line. That should not happen with bound sand because when I use it there is no flash around the parting line.
The exact same thing happened to me using SS sand. In the winter time the CO2 gas was very cold and would not cure the SS sand completely so I would put the mold on a uneven surface and it would leak when poured. To fix this I used to make the molds a few days before and sit them on a even surface when the sun was out to cure them completely. It took me a long time to realize that SS cores and small molds could be put in a microwave oven and cure them without using CO2. I also found out there are liquid hardeners for SS but they have a short shelf life.You can stand a set mold on edge, or place it on a surface that is not completely flat, and during this not-fully-set time, it will actually move and warp just a tiny bit.