This is what HB Body has to say about it.
"2K excellent high build primer with outstanding filling power for all types of paints (synthetics - single coat or base coat). 4:1 mixing ratio with H725 Hardener. It can be diluted 10-15% with 740 Acryl Normal Thinner and 741 Acryl Slow Thinner (reducer). Quick drying and easy to sand."