Clumpy Plistix?

[Trees]

Interested to hear people's experience applying Plistix...

I was putting my first coat on the kiln shelf pieces that will be my forge doors and the K26 firebrick piece that will be the removable divider.  I stirred the powder well with the water to maybe slightly thinner than latex paint to start and used a paintbrush.  On the first brush strokes it would clump massively - like it was instantly drying and clotting together, leaving the areas between the clumps with barely any Plistix on them.  Was similar for both the kiln shelf (high alumina I believe) and the firebrick, but a little worse on the brick.  I tried 'buttering' a couple pieces of the kiln shelf first - not drenching but spraying quite a bit of water on it, but that maybe seemed to make it worse?  Also tried mixing thinner and thicker with no improvement.

The picture was taken after spending a bunch of time smudging out the worst of the clumps.

Is that just how it goes with the first coat, or is there something wrong with my technique?

Also - I've noticed that once the remaining mixed Plistix dries a bit in the container, it seems revivable by mixing in more water.  Wondering if I put a lid on the container, if the same leftover mix could be used in a day or two if a bit more water is added again?

[Trees]

And now to piggyback on this post - after the first real heat of the Kast-o-lite in the forge body, I've noticed some of the dreaded cracks appeared.  I was heating up the forge to finish burning off the stinkies in the cured KOL before applying 2 coats of Plistix to the whole inside.  Am I correct that these cracks can be effectively patched with the Plistix, or should I be trying to get a bit more Kast-o-lite in there first for added strength?