AndysMachines
New Member
Pewter is expensive per KG as it's mostly tin which has a commodity value just like eg. gold. There are other 'low melt' alloys that are cheaper but they often contain lead, antimony, zinc etc... Cap guns were probably made from 'white metal' which is a mix of various things, usually mostly zinc.
Being able to cast metal straight into a flexible silicone mould is a super nice easy cheap and quick way to do it, so the extra cost of the metal saves you a lot. Yes aluminium is cheaper, often free, as you can melt scrap. But you need to work at a higher temperature so need to use different methods such as sand casting or investment casting but the equipment and materials for that cost more, it takes longer and it's harder to make the patterns which often need breaking down into many small pieces and then welding together after casting.
The main advantage of aluminium over something like pewter is that it's lightweight, but that may not be an issue if you're building a static model.
I'm currently experimenting with 'lost PLA' casting. It seems very attractive to be able to go from a 3D print to a real metal part, but to get good results is difficult. You need a kiln that can heat at a controlled rate to over 700°C, a vacuum casting setup to pull the metal into the mould, and even the investment casting plaster is expensive stuff. I've seen people use plaster of paris mixed with sand, but it's prone to failure and doesn't work for complex shapes or intricate detail.
Being able to cast metal straight into a flexible silicone mould is a super nice easy cheap and quick way to do it, so the extra cost of the metal saves you a lot. Yes aluminium is cheaper, often free, as you can melt scrap. But you need to work at a higher temperature so need to use different methods such as sand casting or investment casting but the equipment and materials for that cost more, it takes longer and it's harder to make the patterns which often need breaking down into many small pieces and then welding together after casting.
The main advantage of aluminium over something like pewter is that it's lightweight, but that may not be an issue if you're building a static model.
I'm currently experimenting with 'lost PLA' casting. It seems very attractive to be able to go from a 3D print to a real metal part, but to get good results is difficult. You need a kiln that can heat at a controlled rate to over 700°C, a vacuum casting setup to pull the metal into the mould, and even the investment casting plaster is expensive stuff. I've seen people use plaster of paris mixed with sand, but it's prone to failure and doesn't work for complex shapes or intricate detail.
