30% Soda Ash
70% Helmers Kaolin (it's suggested to try substituting different earthenware clays, ball clays, or kaolin clays into the recipe.
try: Cedar Heights Redart, EPK, Newman Red, and Ravenscrag Slip
Apply very thinly by spraying, dipping, or brushing onto bomedry ware or onto bisque. Over application of this glaze will chalk-up the surface.
The shot above shows the effects of the flashing wash being hit directly by flame and soda...
The shot below is on a canister in a cooler section of the soda kiln. A nice varied and toasty matte surface.
This recipe is from page 58 of 2005's June/July/August Ceramics Monthly.
The Helmer flashing wash on a small canister that was sitting in a sweet spot in the 2009 kiln.