How does one make a start in metal casting?
The simplest way for anyone to learn, the very basics of metal casting, is to melt some lead and pour it into a sinker mould. Thousands of keen fishermen do this to make their own special sinkers, but many don’t realize they could do much more with metal casting, if only they would explore it just a little more.
There a few good reasons for this simple basic approach.
1. You’ll learn first hand about finding some scrap lead and cutting it into small pieces to put into the melting
vessel, pot, or crucible as they are called in real foundries.
2. You’ll have to make or find a fishing sinker die, these are normally made of two parts, (split die) very often
they have been cast out of aluminium. But you could fashion one from plaster of Paris, this exercise will give you “basic” pattern making experience.
3. If you examine one half of the sinker die you’ll find the following. At the very top is a small cone shaped cavity or depression, this is called the pouring basin, just below that will be a short narrow channel, this is called the sprue, the hot metal flows swiftly from the pouring basin into the sprue and into the mould cavity.
4. You wont need much heat to melt lead, you could melt it on your kitchen gas hot plate, but DON’T do it inside, breathing lead fumes is dangerous to your health, set up a small gas cooker outside, such as a camping gas cooker to do your melting.
5. A solid tin, or small metal container will suffice for your melting pot, to make pouring into the fish sinker die easier, rap a pair of pliers and shape the rim of the container into a pouring spout, you will need to be accurate when you pour the molten lead into the die.
You may also need to make some sort of a handle on the side of the melting vessel so that you can hold it with a pair of pliers to pour the metal.
THE MELTING AND POURING SESSION.
Once you’ve got all of the gear organised, it is time to proceed with your project, light your gas camp cooker, turn the flame up about half throttle, put your melting pot over the flame, place the small bits of lead into the melting pot, you may have to do a trial run to see how much metal you’ll need to fill the die, melt more metal than you need, as there is nothing worse than NOT aving enough metal to fill the mould or die.
Prepare your die well before you’re ready to pour, the best way to hold the die together is to place a light spring clamp around the body
of the die, the mating surfaces of the die must be neat, you do not want molten metal to run out of the die after you pour.
As the lead melts, an oxide or scum will develop on top of the metal, this dross as it’s called can be scoped of and discarded. Don’t leave it in the pot as it will block the sprue when you go to pour the metal.
In real foundry conditions when melting aluminium, a flux is generally used to control the oxides that form, and a degassing compound would be used to clean the metal; it purges the oxides and impurities, and leaves a nice clean sound metal to pour.
But you wont have to do this when you melt lead.
Once you have a taste for this very basic approach to casting metal, you might want to explore further, take a cruise around our web site, use the search function to find what you want.