Separation and settling

Two problems that look alike and happen at opposite ends of the process.

Two different faults

Settling happens in your pouring vessel, before the product exists. Anything solid suspended in the melt sinks while you work.

Separation happens in the finished stick, when a component comes out of the matrix.

The first produces a batch where the first tubes and the last tubes are different products. The second produces a tube that fails later.

Settling in the pot

Pigment, mica and any powdered addition will sink in a low-viscosity melt. Pour fifty tubes from a pot and the last ones carry noticeably more color than the first.

Stir between pours, not just at the start. Work at the cooler end of the pour window, where the melt is more viscous and holds the dispersion.

Disperse properly in the first place, pigment ground into oil, not stirred into the melt as dry powder.

And pour from a vessel with a spout rather than dipping, so the whole batch stays moving.

Separation in the tube

This is the sweating fault under another name when it is oil, and a formula fault when it is anything else: an ingredient that was never really soluble in an anhydrous base, held in suspension only while the melt was hot.

Water-based flavorings and some extracts are the usual culprits. They will not stay.

Catching it before it ships

Pull the first, middle and last tube from every run and keep them together. Compare color and feel. If they differ, the batch settled and you now know at what point.

It costs three tubes and it is the only check that catches a fault which is invisible in any single unit.

References