The Mouldmakers Handbook - Making hollow casts

Here I found some pages on making hollow casts by rolling the chosen casting material around the mould before pouring it out.

I have included these pages because they describe a similar method to the one I chose to make my pen.

I tried using car body filler slush to make a hollow pipe form, only I continued to swirl the mixture around inside the mould until set instead of pouring it out.