Job down at my local brewery and managed to get hold of a Stainless Steel Beer Keg, thanks John Tower Brewery!
Whipped the top off using one of my new toys, Plama Cutter
Cut air hole two inch up from the bottom
1 1/2 in lenght round stainless steel to form air channel. Held in position to tack weld.
Tack welded to the inside.
Used the cut out for the air hole hole to blank the filling hole
Have filled the bottom with 2 inch of 5 parts Vermiculit to 1 part cement and the sides 1 1/2 inch of same mixture.
Drying out at the moment. More pics to follow.