I have just finished viewing your web site. It is most informative and gave me a good idea of what is required to make models. So that you know that I am serious, I am in my seventies and coming back to railway modeling which I did many years ago. In those days I bought all my rolling stock complete or as metal kits. Now, I would prefer to build from kits. It not only keeps me occupied but ready-built rolling stock is more expensive that I can afford, at around $40-$50 a piece.
The attached image is a HO scale railway wagon in white metal. This is a very old kit and is no longer available. I would like to make a mould to cast it in polyurethane? Or what ever material you recommend.
After reading the notes on your website, I tend to lean towards silicone for the mould. What would you recommend as a casting agent? The heavier the better but I would not be disappointed if it wasn’t heavy. I also need release agents. Do I need it for the silicone? Do I need it for the release of the two-part mould? What else do I need? As you would have gathered I am new to this and will be guided by your advice. I would also appreciate it if you could tell me where I could find instructions (book/video) that would tell me how to construct the basic mould box so that the casting medium flows correctly and also allows air to escape.
Some of my old rolling stock still exists in reasonably good condition. With a little care I could disassemble these and maybe have 5 or six different models. So I have a requirement for say 10 different moulds with anything from 20 to 50 castings from each.
If it is possible, could you please construct a shopping list for me to cater for the above? I will then purchase these items from your firm. If the book/video is available I will also purchase that from you. I hope I am not wasting your time.
Thanking you in anticipation.
Thank you for getting in touch with us. I am also a model railway enthusiast and have played around with making moulds of my existing model kits. I would certainly recommend silicone for the manufacture of the moulds.
I have experimented with the use of metal powders in my casting resin to increase the weight and the results were quite good. I used CraftCast 75 for the casting resin and mixed in up to 50% iron powder to the mixture, making sure I mix the metal powder in before mixing the two parts A + B of the resin together. The reason you add the metal before is because once the resin is mixed, you will only have 2 – 3 minutes to get the resin mixture into the mould before it starts to set.
You don’t need a release agent when casting polyurethane resin into a silicone mould.
We are currently in the process of developing a mould box kit for sale but this is a few months off. Until then we recommend using small pieces of timber or lego to construct a wall around the original piece and to ensure it is water tight, apply non-drying clay such as our plastelina to the corners and edges of the wall.
A shopping list would be something like:
Aldax CraftSil 750 Silicone (to make the mould)
Aldax CraftCast 75 Resin (to cast into the mould)
Aldax Plastelina (non-hardening clay)
Unfortunately we don’t have a video on this process yet, except for the online videos on our website which goes into some mould making with silicones.
I hope this helps. Please get back to me if you have any more questions.