Latex is so much cheaper than silicone that I'm now trying to make all possible moulds using latex. Looking at a master for a high heel sole, I got an idea I just had to try. I thought that it would be possible to make a tubular mould using latex by placing the opening under the toe part and attaching the master to a support only from that place. The picture below explains this better than any words. I used a square piece of mounting tape to attach the master to the cardboard structure.
Then I applied several layers of latex, letting it dry before applying the next layer.
Here you can see the size of the opening. It is fairly large, because the entire master needs to fit through it.
This is the trickiest part of removing the mould. You need to roll the mould over the highest part of the master, because too much stretching could tear the latex at this stage.
Here is the mould turned right side out. I'm going to let it set for a few days before casting, because removing the castings will require a lot of stretching and I want to be sure the mould can take it.
It'll be interesting to see how this will work. I got the master out of the mould, so removing the castings should not be a problem. Getting air bubbles out of the heel could be a challenge, but I already have a theory on how to do that. We'll see how it works once I get to use the mould.