What Rob mentions about Mas is correct. If the previous coat has hardened beyond tack you will get surface tension pulling the wet coat and spots that are not covered. The Mas likes to be overcoated before it has gone tack free, and then works very well.

I know Rob advocates a seal coat, but with Mas it may not be such a great idea, its viscosity is low enough that I find it penetrates fine without a seal coat and stays wet long enough that full saturation is achieved as well. (Provided temps are adequate). I like the Mas, but on the occasion that I left it even a little too long it (ie, beyond tacky, but still thumbnail dentable) it punished me just a little. I use the slow hardener.

I still use it, but don't seal coat and I never let it dry completely before fill coating.

I have used SP systems, West and Mas. I like the Mas best.

Et