Sodium metasilicate as an alkali accelerator

[Jemzyboz]

The other day Daniel Keating mentioned on Facebook that for V3 of his pyrobutter, he subbed the hydroxide for sodium metasilicate and ammonia alum (which was used for thickening the solution).

Now I realise that sodium metasilicate is also used for soap making like hydroxide and is less basic at about pH 12 but I have never seen it mentioned for film developers before. Scoured my books and the internet for any mention of it for photochemistry use but no luck.

I wonder why has it never been used before?

 

[Alan Johnson]

Because sodium carbonate and hydroxide are cheap as chips and have been used for 100+ years?