Beer coating

[Loris Medici <mail@loris.medici.name>]

Dear Henk,

I tried beer coating tonight on a thoroughly cleaned and dried plain
aluminum sheet. Unfortunately the coating washed away in the cold water
bath. What could I have done wrong?

1.  I opened a can of Pilsener and let it sit in the fridge for 24h
2.  I took 100ml of the can and waited to normalize to room temperature (21C)
3.  I mixed 1g of caustic soda (NaOH) into the beer
4.  I mixed 10ml of sodium silicate into the beer
5.  I stirred thoroughly
6.  I immediately brushed the mixture onto a clean sheet of aluminum using a
    foam brush
7.  I dried using a hair dryer in the middle setting
8.  For the sake of getting an even primer coating, I coated the sheet once
    more with the primer
9.  Same as 7
10. I washed the sheet gently rocking a tray

The coating dissolved and left the sheet during step 10. BTW, FWIW, when
you put the sheet into water you can hear a fizzing sound (but can't see
any bubbles)...

???

Thanks in advance,
Loris.

P.S. I couldn't manage to coat the Forex sheet with beer + silicate.

P.S.2. If I can't make it work, will try to put plain acrylic gesso (which
doesn't hold gum by itself) on the sheet, sand and then coat it with beer
+ silicate

P.S.3. I prefer to be able to coat the sheet w/o any acrylic gesso since I
plan to buy white painted (enameled?) aluminum sheets later -> I just want
to skip the whitening step for relatively conventional photographic
prints...