You do not need an accredited laboratory to release batches. You need eight measurements, done consistently, with written pass criteria and someone accountable for signing them off.
Test every batch, without exception
- Viscosity, density and pH on liquids; particle fineness and set time on powders. Minutes each, and they catch most dosing errors.
- Solids content by oven — the single most useful number you will measure, because it is what the customer is paying for.
- Dry film appearance on a drawdown card, kept and dated for comparison.
Test weekly, and on any change
- Tensile adhesion to a concrete block, and elongation on a cast film.
- Water resistance under a head, on a sample from that week's production.
- Run these whenever a raw material lot changes, whatever the schedule says.
Keep records that can defend you
- Retain a sealed sample of every batch for at least two years, labelled and stored out of the sun.
- Record the raw material lot numbers used in each batch. Without that link, a supplier problem is untraceable.
- Write the release criteria down and let the lab, not production, sign the release.
The short version
Eight measurements, consistently applied, prevent nearly every commercial disaster a young plant runs into.