The message
from "dennis@home" contains these words:

Very unlikely. The hydrogen has a far greater affinity for the oxygen
than
the carbon.

So how accurate is the formula dennis@home previously stated?

"C3H8 + 4(O2+4N2) === CO + 2CO2 + 3H2O + H2 + 16 N2"

I am no chemist but ISTM that that could equally well be written as:

C3H8 + 4(O2+4N2) === 2CO + CO2 + 4H2O + 16 N2


That would be correct if there were an ample supply of oxygen.
There isn't so you get the CO and the H2 produced.
The CO reduces the oxides in the glaze (changing the colours).
The hydrogen is left over AFAICT.
This is what may cause an explosion.

I was pondering TNPs remark on Hydrogen having a much greater affinity
to hydrogen in a reducing atmosphere. If there was an ample supply of
oxygen surely there would be no CO produced.

--
Roger Chapman