Mason 4x2 Hobby evaporator bricking question

[bunkerchump]

So far, I bricked the entire unit except for the fire wall after the step-up. I have a few questions:
1. Should the wall start immediately at the step-up?
2. Does it help if the wall is built at a slope, or would a right-angle from the floor be ok (the former involves cutting more brick at an angle for a gradual step-up)
3. How far from the bottom of the pan does the wall need to be at it's highest point? Three layers of full size fire-brick will get me to 2.5 inches or so from the bottom of the pan. Two layers of full size and one layer of split will get me 3.5 inches or so.
4. How far does the wall have to extend back toward the stack?
5. Is it necessary for the wall to be cemented in?

Some of this might be trial and error, but was hoping to gain from some others' experience.

Thanks in advance

[millscrest]

For what its worth, I have a mason 2x6 that i got last year and really like the unit. I bricked the entire unit with split bricks and did not slope them back as you are talking about. It worked just fine. Try it that way and if it doesnt work for you, then try to slope the bricks back with a smaller amount of distance under your pan.

[bunkerchump]

For what its worth, I have a mason 2x6 that i got last year and really like the unit. I bricked the entire unit with split bricks and did not slope them back as you are talking about. It worked just fine. Try it that way and if it doesnt work for you, then try to slope the bricks back with a smaller amount of distance under your pan.

Thanks, Millscrest. How much space between the top of the fire wall and your pan? About 3 inches?

[millscrest]

I lined the entire arch with the split bricks including the bottom. The total distance between the bottom of the pan and the fire brick on the bottom is about 8 inches. So far this has worked for a good draft for the fire. If you look at Bill Masons website, there are a few pictures of a bricked evaporator. Any other questions, please continue to ask.

[millscrest]

www.wfmasonwelding.com. On the top of this web site cllick on the bricking instructions and there are some picutres. I did mine the same way.

[bunkerchump]

I lined the entire arch with the split bricks including the bottom. The total distance between the bottom of the pan and the fire brick on the bottom is about 8 inches. So far this has worked for a good draft for the fire. If you look at Bill Masons website, there are a few pictures of a bricked evaporator. Any other questions, please continue to ask.

I used full brick for the fire box, but splits for everywhere else. I did see two different techniques on the website: one had a fire wall at the step up, and the other used patio bricks? to first build up the step up area, then with the half bricks over it. I moved more toward the former. I just measured again, and the bottom of the pan and the fire brick on the bottom is 9 inches. I would think that my boiling rate would be lower if I left it this way, since much of the flames would not be concentrated on the bottom of the pan and would instead escape through the stack. But in starting to build up the fire wall, I became concerned that I would limit the oxygen flow and thus not burn as hot.
Here's a pic of where I am. The fire wall on the right is 3 full brick and gets me to 2.5inches from the bottom of the pan. The one on the left is 2 full and one split which gets me a little over 3.5. 6185

[millscrest]

Thats a tough call. You might want to maybe try it with one layer of full bricks and see how the air flow is and later add another row or take ot out. I left mine with all splits and I get about 10-12 gph

[flhr10]

Maybe it would work better if the fire wall were built at the rear, leaving just enough room for the smoke and heat to exit out the chimney. This way all of your heat would be under the pan for the longest time before going out the stack. My Empyre outdoor boiler has a water filled baffle at the rear of firebox that holds the heat and flame from going straight out the stack.