Trouble boiling more than 1 steam pan - Concrete block arch evaporator

[BucksMaple]

This is the first year I've tried this, so I built a concrete block arch based on the number of YouTube videos that I watched. The blocks are two blocks high on either side, i put a metal sheet on the ground so it can be cleaned out easier. I've got three steam pans but only one pan (the back one next to the exhaust stack) seems to ever boil even though I have the fire going throughout the entire Arch. Does anyone have any tips on how to maybe better design the standard firewood Arch?

Would elevating the wood off the ground help? Is my exhaust stack too high? Why won't the front pans get hot enough? I've tried opening and closing the intake bit it doesn't seem to matter...

[RileySugarbush]

A few quick suggestions:

You definitely want to set the wood on a grate so the air comes in and runs up through the fire. Space up behind the grate with more block to within an inch of the back pans. form up a piece of sheet metal or buy an L shaped piece of ducting from home depot. Two of these pieces are shaped together to make rectangular heating ducts....2 or 3 x 12" I thinkYou can hang one on the front of the arch to keep air from coming in over the fire and force it to go into the area und the grate. If you and some more on the inside walls of the block it will protect the block a little and may keep them from failing for a year or so. To do all this you may want to raise the arch another course of block.

[BucksMaple]

A few quick suggestions:

You definitely want to set the wood on a grate so the air comes in and runs up through the fire. Space up behind the grate with more block to within an inch of the back pans. form up a piece of sheet metal or buy an L shaped piece of ducting from home depot. Two of these pieces are shaped together to make rectangular heating ducts....2 or 3 x 12" I think You can hang one on the front of the arch to keep air from coming in over the fire and force it to go into the area und the grate. If you and some more on the inside walls of the block it will protect the block a little and may keep them from failing for a year or so. To do all this you may want to raise the arch another course of block.

This is great, thank you so much. So what you are saying is to get a grate (does home depot have something like this?) and set it on a couple bricks to elevate it? What do you mean "space up behind the grate with more block to within an inch of the back pans"? I'm not following.

[ecolbeck]

You want to build a ramp behind the firebox out of bricks/block/rock to push the fire as close to the bottom of the pans as possible (without cutting off all airflow,obviously).

Cheap grates can be bought on amazon and perhaps at home depot but the cheap one I bought melted by the end of the season. Other folks here might have suggestions. elevate the grate with bricks (like you said) in order to encourage airflow up and through the fire.

As the other poster mentioned, a door that forces air to go under your grates is essential. A piece of sheet metal will do.

[Russell Lampron]

You can build a grate out of old bed frame angle iron if you have a welder. You can even bolt something together if you don't have a welder.

[RileySugarbush]

This is great, thank you so much. So what you are saying is to get a grate (does home depot have something like this?) and set it on a couple bricks to elevate it? What do you mean "space up behind the grate with more block to within an inch of the back pans"? I'm not following.

If your arch is three pans long, your fire should be limited to the front half, maybe about 20" from the front. You need to fill in the area behind the grate for two purposes. One, to prevent the air from going through the grate and up the stack, missing the fire. Two, to force the hot combustion gasses up and tight against back pans.