The crucible is made to withstand high heat to ensure you’re able to melt your desired substance in a reliable container. Historically, crucibles were made from clay or ceramic—and often still are. However, they can be derived from any material that can endure extreme temperatures.
Clay is ideal because it lacks metallic properties that prevent the material from messing with the alloy of the metal you’re melting. The secret to making your crucible last is to heat-treat it properly when it’s new. Knowing how to properly heat a crucible the first time and every time after will ensure its success longer.
Heat Treating Considerations
When you get a brand-new crucible, it needs to be heat-treated before its first use. Heat-treating—or “curing”—a crucible sets it so that when you use it later, it doesn’t crack or break down and expose you to extremely hazardous temperatures of melted metals or other substances.
If you acquire a crucible that’s been used, it will need to be cleaned before you use it. So, wash your crucible with water and dry with a paper towel. Ensuring all residue from other projects has been removed is important. However, doing this will add moisture to your container that will need to be removed. When possible, start completely fresh. Cast Master Elite has clay graphite crucibles for sale to ensure quality and to help you have a full history of the item you’re working with.
If moisture is on your crucible when you try to heat it—even if it’s not visible to the naked eye—it will flash boil. This will cause the item to crack or explode, which is very dangerous. You don’t know what dampness the crucible has been exposed to, so you must temper it to eliminate any moisture.
In order to heat-cure your crucible, do the following.
- You can begin by putting the container in the oven at 300 degrees for an hour.
- Next, temper the crucible by putting it in the furnace. Your flame should be orange and yellow.
- Slowly heat the container, starting on low power until it’s a red-hot 1110 degrees Fahrenheit.
- Once it’s fully heated, let your crucible cool.
Once you’ve been using your crucible regularly, you’ll get a feel for how to push it and how to maintain it the best. Some like to use Borax during the tempering process as they believe it will help prevent cracking and breaking. Any time you heat your crucible from a cooled state for an extended length of time, slowly raise the temperate to 200 degrees Fahrenheit before heating it the rest of the way.
Crucibles are made to withstand a lot. To get the most out of yours, consider the best practices for how to properly heat a crucible. It’s not ideal to have to stop in the middle of a project because yours cracks. The better you follow this process, the more successful you will be in your endeavors.