I’ve been thinking a long time what is the best way for casting the bulb. The best option seems to me melting the lead in a gas cylinder. Luckily I found an old gas cylinder in my father’s shed. But what is the safest way to cast the 75 kg of hot liquid lead without putting yourself in danger. So my father (an engineer) and I made some thoughts. It makes you very creative when there is enough stuff lying around in your shed. The result was a very stable construction with scaffold tubes. It is transportable and detachable to a minimum size to be stowed away in the workshop or transporation in the car. We where able to do small adjustments to put it in the perfect position to the mould and set it up for the casting job. It was created from leftovers that have been lying around for years. This is how sustainable boat building works.

After we had planned the framework we set about preparing the melting pot. First i cut the top of the gas cylinder with an angle grinder. It is important that it is completely empty (danger of explosion). Propane and butane is heavier than air and so there is still some gas left in the tank even if you opened the valve properly. It is best to unscrew the valve and fill it up with water so that all the remaining gas escapes. Then we measured the level of liquid lead in the cylinder. This is important to determine the center of rotation when pouring the lead into the mould. 75kg lead has a volume of approx. 7 liters with a specific weight of 11 kg lead per liter. We filled 7 liters of water into the cylinder, measured the water level and marked this level on the outside. Above the middle of the water level we positioned the center of rotation. We made the fixing points for the axle and the liftingbar from bigger metal tubes and the handles that we cut off before. After a busy day I was happy with the construction which gave me headaches for a long time. I could hardly wait the big day of pouring the lead.