30 day challenge - day 1 - kitchen chemistry, take 2

Today's work (actually on 1 December) was to have a second go at slaking plaster with the 30 min method to make real gesso.

I've spent the past hour stirring, pouring off, watering and stirring some more. I *think* I've reached Ph neutral, but the litmus strip is hard to confirm in artificial light. So I've poured the plaster sludge into two plastic containers, and will leave it overnight.

If it settles I can double-check the Ph, then let it dry.

If it hardens into plaster - I guess I have two big flat chunks of plaster to carve.

30 day challenge - is this really what slaked plaster looks like??

So, day 2 of the challenge, and I'm still chasing slaked plaster for gesso. Yes, I'm tired of this too.

This morning this is what my 80ml of dry plaster + 1.6L of water (with one round container's worth of water already poured off) looked like:


(Yes, we have a 70s-era fake-marble-laminate countertop. We rent. The redeeming feature of the ugly kitchen is its size.)

In daylight, I'm still not certain if the Ph is neutral or not - what looked like ranging into 'yellow-green' on the litmus paper (neutral) in artificial light was pretty yellow (alkaline) in daylight. Sigh.

Am I doing it right? I've no freakin' idea.

I'll keep pouring off the water as the plaster settles, but short of getting better-quality litmus paper, I've no idea how to determine if my plaster is ready to use. I get the impression that most scribes who go this route do this once, in an enormous batch, and then happily never to have to do it again.

Of course, if it does work, I probably won't have to do this again...and will have loads of dental plaster to pass on! I swear I could make up gilding materials kits...hmmmmmmm.