Firebox size

[RC Maple]

This is my evaporator setup that I've just firebricked. With the firebrick in the barrel the grate sits a lot higher. If I measured from the grate to the bottom of the pan it would be 12 inches. The grate is 16" wide and there are 4" from the brick to the grate as pictured. By shortening to a 13" grate I could lower it 2" and have 14" from the grate to the bottom of the pan. Should I come up with a smaller grate or is 12" good?

[Sunday Rock Maple]

Nice looking Job!

I'd try it as is, you need room for ash to fall and still keep air flow under the grates -- might have to fire more often though as you don't want to hit the pan bottom with the wood and get a high spot that could burn quicker (done that).

[smokeyamber]

Nice looking arch build, I have a barrel arch and built up a wall after the grate with perlite and then put firebricks over it, this forces the heat up into the back of the pan for better boil. I used set in restauraunt pans so my clearance was less than what you have and it was fine. You will need to use small wood ( wrist sized ) and feed often. My boil rate is around 5gph though I added a blower last season which helped keep the boil going better. You will enjoy the experience and like everyone here expand to fill that shack ;)

[Indiana-Jones]

Hi, looks like she will boil like crazy. Is the blanket under the brick 1 or 2 inches thick?

[RC Maple]

The insulation blanket is 2" thick. I bought this at an auction and whoever made it had the blanket in there already. As far as building up a wall, the 2x2 pan takes up all the room infront of where the stack exits. If I did build anything up behind the 20" grate I think it would only force the heat up the chimney and miss the pan (the barrel is 32" long). Is that the same size barrel you have?