The material is possibly one of the easiest; lead. However, we are still dealing with metal and so rules apply. Everything that is about to have molten lead poured onto it must be dry. If any moisture is on a surface, liquid lead will immediately boil the water, causing it to explode under the lead.
Bearing this in mind, I first tried casting with concrete. The thinking behind it was that the concrete would be fully dry and very durable. This was not the case, the whole thing fell apart, so I moved into a substance I had all along; plaster.
The first tentative pouring into the mould was done at arms length as I wasn't sure how the plaster would react to having 327.50°C (621.50°F) lead being poured into it. All was well, but if you try this yourself, please bear in mind I made sure everything was bone dry. The plaster had been heat dried for a few hours at least and sounded very tinny and light when put on a surface, not clunky as it does when holding water.
Now to what really matters, the result. I am not going to tell you how I melted the lead, but suffice to say, it would have been at the minimum temperature and so cooled and hardened very quickly. It resulted in only parts of larger leaves being moulded as the lead went off before it hit the edges.
Smaller leaves worked better, such as this goat willow leaf. The plater mould remained intact as well.
However, the most surprising cast was one that was left field to say the least. A horse in the paddock in the summer had been busy, and wherever it left it's droppings, marvellous fungi emerged. Taking one of these, I placed it into a silicon mould, just half of it submerged in plaster. Even the gills show in the final lead cast. Who would have thought such fine detail would emerge?
Even the tiny pitting on the surface of the hood show. This is a very delicate organism indeed
I am amazed.
Phase III will show the final idea for casting in lead; using sand.
The sand has to be wet or it won't stick together, and so I am nervous as all I have just said about keeping all very dry is about to be ignored. A friend has made a couple of wooden frames for me and now all that needs to be done is pack in the sand; level off; add leaf (whatever needs casting) and the second frame added and more packed sand. If all goes well, the next blog post will show what happened next. Using a heat source of a butane burner, temperatures will rise.
