Tempilaq temperature indicating liquid 399°C / 750°F
Tempilaq is a temperature-sensitive indicating liquid used to verify that your brass cases reach the correct temperature during annealing. This 750°F (399°C) version is the standard used by most reloaders for annealing the case neck and shoulder.
Usage is straightforward: apply a small dab of Tempilaq to the inside of the case neck using the applicator brush in the cap. The liquid dries quickly to a matte finish. When you heat the case and the temperature reaches 399°C, the coating liquefies. That's your signal that the correct annealing temperature has been reached. Accuracy is guaranteed at ±7.5°F (±4°C), so you can be confident you're within the right temperature range.
How to use Tempilaq when annealing
Always apply Tempilaq to the inside of the case neck, never the outside. The outside comes into direct contact with the flame or magnetic field, which would cause the coating to burn off rather than liquify. On the inside, you're measuring the actual temperature of the brass itself.
Most reloaders use Tempilaq to dial in their annealing process: treat a few test cases, check when the coating melts, note the time or setting, and anneal the rest of the batch based on that setting. This way you don't need to treat every case with Tempilaq, but you have the confidence that you're consistently working at the right temperature. After annealing, any residue is best removed with a cotton swab while the case is still warm.
Why 750°F (399°C)?
When annealing cartridge cases, you want to heat the neck and shoulder to the point where the grain structure of the brass reforms. This happens effectively at temperatures between 350°C and 430°C. The 750°F (399°C) Tempilaq sits right in the middle of that range, making it the most popular variant among reloaders. At this temperature, flash annealing occurs in just a few seconds, which prevents heat from migrating too far towards the case head.
Specifications
• Brand: Tempil
• Product: Tempilaq temperature indicating liquid
• Indication temperature: 399°C (750°F)
• Accuracy: ±4°C (±7.5°F)
• Colour when applied: dark green
• Function: dries to matte finish, liquefies at target temperature
• Application: inside case neck, using brush in cap
• Non-flammable
Pair with your annealer
Tempilaq works with all types of annealers. Use it to dial in your Ugly Annealer by Derraco with a Bernzomatic UL2317 pencil flame torch. Regardless of which method you use, Tempilaq gives you the confidence that your brass is being annealed consistently.
