S
SteveO
Guest
Certain types of pattern masters can be made quite easily through etched components, and this is the method I'm going to use for some of the castings for the upgraded 04 I'm working on. The only comparable component on your steam prototypes and my diesel is your chimney and my exhaust stack. The easiest way to achieve this is by turning the main component part and then fabricating the curved fixing plate with an appropriate material, depending on what you're casting with.
However, below is one example of where I can use the etched layer method:
This is the brake actuator bearing, highlighted in red. It's conveniently 3 frame thicknesses so can be made from 3 layers. This is it separated from the drawing so it's easier to see (plan and section):
The first layer will contain the rear plate, the bolts and the first layer of ribs. The height of the bolts will be full thickness, but the plate will be half-etched. Below, you can see a simplified section of this first layer:
The next two layers containing only rib and bearing detail, but when all three are soldered together will produce this:
I can then file away the bevels of the ribs and this will be a solid pattern to produce a casting from. This will almost certainly be cast in pewter in a vulcanised mould so the solder I will use will be 188C. Vulcanising can get pretty hot and the pressure is quite intense so I have to make absolutely sure that the layer joins are perfectly sound.
The air tanks you can see in the first picture will be constructed with thick-walled tube and soldered end caps, which will then be filed and sanded to shape and also cast in pewter.
This is intended more as a practical way of building patterns quite quickly from etched components, rather than constructing them in a machine workshop – which I don't have. There are other ways of achieving this with a full workshop, but all my masters should cost around £45 to build this way, instead of spending several £hundred or a couple £thousand on a lathe, mill, etc.
However, below is one example of where I can use the etched layer method:
This is the brake actuator bearing, highlighted in red. It's conveniently 3 frame thicknesses so can be made from 3 layers. This is it separated from the drawing so it's easier to see (plan and section):
The first layer will contain the rear plate, the bolts and the first layer of ribs. The height of the bolts will be full thickness, but the plate will be half-etched. Below, you can see a simplified section of this first layer:
The next two layers containing only rib and bearing detail, but when all three are soldered together will produce this:
I can then file away the bevels of the ribs and this will be a solid pattern to produce a casting from. This will almost certainly be cast in pewter in a vulcanised mould so the solder I will use will be 188C. Vulcanising can get pretty hot and the pressure is quite intense so I have to make absolutely sure that the layer joins are perfectly sound.
The air tanks you can see in the first picture will be constructed with thick-walled tube and soldered end caps, which will then be filed and sanded to shape and also cast in pewter.
This is intended more as a practical way of building patterns quite quickly from etched components, rather than constructing them in a machine workshop – which I don't have. There are other ways of achieving this with a full workshop, but all my masters should cost around £45 to build this way, instead of spending several £hundred or a couple £thousand on a lathe, mill, etc.