1/32 model train car mold procedure

[machiningfool]

I said procedure, as if this is the way to do it, well there are many ways to do it, but this is the way that I make a model train mold. This time, instead of machining or patterning a completely new car side, I liked the detail of an observation car that I bought and decided that it would be easier to just make a mold from it, saves quite a bit of time. I will, from time to time add pictures of my progress. This beginning picture is the gluing of the car side to a piece of 1/4 inch piece of plexiglass and claying up around the edges and windows. This is very important because, if you don't, the urethane, when pouring, will leak through the small openings and spoil the mold, cause bubbles, and a number of other problems. This will be a two piece mold, this is the first half. After making this half, I will prepare the inside of the car side and pour the other half, so that both sides come out smooth and easy to manage. Here is the first step, more to come. Bob.

[machiningfool]

I have blocked the pattern and placed 1/4 by 3/8 strips of plastic for alligning the second part of the mold. Now, all that is required is spraying parting compound and pouring with urethane. Bob.

[machiningfool]

Here is a picture of the first part of the mold poured with urethane. Next I will add some body to the thin side and then pour the second part of the mold. Bob.

[machiningfool]

This is how I give the pattern some thickness, because the original pattern is metal and thin, too thin to reproduce a pattern for an epoxy part. This is partially done, will finish tomorrow and then possibly pour the second part of the mold. Bob.

[Paul Jones]

Bob,
I am following along to see how you do this. You will have a nice looking product based on the original car but there is more to make before the new cars will be rolling out of the shop. Will the original observation car sides clean-up and be return assembled in its original condition or permanently assigned to the pattern shop? Thanks for posting your progress.
Paul

[machiningfool]

Yes, the parts are not damaged, urethane doesn't attack paint, or anything else. The only thing that happens to parts of the pattern, is when I apply super glue to the inside of the pattern, but, you won't be able to see that when it is reassembled, so I will still have a good looking obs. car. Bob. Do you make molds or patterns? I see you live in Yorba Linda, I used to live in Chino on Lime Pl.

[machiningfool]

Here is the pattern finished except for seal the wood and sprayed parting compound. Bob.

[machiningfool]

Here is a picture of the pattern ready to pour the second half of the mold. Bob.

[Paul Jones]

Bob,

I do not make patterns but I am interested in the work you are doing for the larger scale model trains. I have had a life-long interest in trains and attribute a lot of my designing, woodworking, machining, and electronic skills to my early years doing scratch building HO model railroading.

I have lived and owned several properties in Yorba Linda since 1978 and have seen tremendous growth and development in the area. I will send a PM.

Paul

[machiningfool]

I am waiting for supplies, so I started a pattern for a six-wheel truck for the car. The original is made of metal and looks good, but I am making this out of resin, hope to make it so it is sprung. I made this pattern on my cnc and machined it out of Bondo, cuts easily. I will make a urethane mold, when this pattern is finished. Bob.