whats wrong with my arch?

[dwyerja]

I recently made some changes to my fire box. Before I had a large fire box 2x4 the length of my pan no arch. I cut it up this year and put an arch in it but doesn't seem to boil hard. Firebox is now 2ft by 20 inches deep. I have fire bricks on the base Of fire box and arch. Any advice would be great. 11480

[sams64]

Are the bricks creating a restriction right before your stack base? Its hard to tell from here, but, it looks like that could be an issue.

Sam

[dwyerja]

There is about 1.5 inches between stack and top of bricks.

[mellondome]

Where is the air getting to the fire from?

[Big_Eddy]

What size stack, and how tall?

Where does the air enter? Should have 1.5x the square footage of air inlet area as smoke stack. (~100 sq in)
Is your fire on a grate? How much gap between the grates? Keep the gap openings to at least the square footage of your smoke stack.
How much space under the grates - 4-6" minimum and keep the ash clear.
How much gap is there beneath your pans? With a 2' wide arch, you can go as little as 2", but no less.

What wood are you firing with? Is it split small and super dry? How much and how often?


Most common problems are wood too large, wood not dry, and not enough air or draft.

[dwyerja]

My stack is 24 inches tall, tapered to 7 inches and is 7 inches deep. I then have 8 feet of stove pipe on it. Air enters through the door with a draft slot when wide open 2inch by 7 inches. I can open the door for more air but doesn't seem to make a difference. Wood is sitting directly on 2 inch fire bricks no grates. At the peak of the arch there is about 2inches gap between. Wood is good and dry, maybe could be split smaller.

J

[Ausable]

A couple of things I would do - Put a burner grate in - so the fuel sits on top of the grate and air can come underneath grate to support combustion. Looks like You have an ash drawer of something with a small handle on it at the bottom of the arch? Make an ash cleanout door on a hinge that can be opened for combustion air to get under the burner grate and it can be used for shoveling out ashes. Hey! It looks nice.

[chad]

My guess would be you need to get the fire up off the floor and onto a grate of some sort so it can breath

[dwyerja]

Okay I can put a grate in and get fire up, what about arch, should it start slopping back at the bottom of the fire box or now the grate? It doesn't look that great, I used all scrap steel because want to get it right before I make an investment.

[birdmancf]

I've got a homemade rig too. Very similar. But no slope. I want the flame to be tickling the bottom of the pans for the greatest distance possible. To me the slope allows a shortcut to the flue, where the flames don't need to touch the front-most parts of the pan(s). Others thoughts may differ. You have to decide and/or tinker with it. It's part of the fun.
Others have said the other big need. Air, some more air, then how about some more. Over and under, split it 60-40, 70-30. The grate and hinges on the ash door will introduce it under, over is a bit more difficult. Your setup is perfect for air from behind and under with a blower. You can get more heat from your fire and have it be more efficient.
Either way what you have is going to work. It will work better than some, but perhaps not as well as others with more design features. The fun in making your own is the ability to tweak performance without worrying about damaging something you've payed so much for.

[dwyerja]

Thanks, that makes sense with air under and over, guess I need to cut some more! Any other suggestions?

[beaglebriar]

I'd start with just getting air under the fire. Looks like your slope should be fine. I'd experiment with blocking some of the flow at the front of the slope as well (add a layer of bricks across the front). See if it has an effect on the boil. The idea is to have as hot a fire as possible but give it time to work on your pan.

[nymapleguy607]

Hows your draft? when you open the door will the stack pull the heat and flames back? If not try adding another section of stack

[dwyerja]

When I open the door the stack is still pulling the flames/ smoke, I guess I will start with getting the fire off the bottom and get some air under it and work on the bricks to see if that will change anything. Thanks for the help I will let you know how I fair out.

[theguywiththename]

Personally I have found that having the fire out the front works well-mine sits 14" or so out the front. I regret not pushing out the front more for the same reason mentioned before- most time for the flame to touch the pan. I also regret not making my box longer to acomadate longer wood- 30" long wood is easier to handle IMO then shorter stuff. I have 2 channels that come from a cavity in the back of the arch that serves as distribution and preheat for my forced air. When the forced air isn't in use, I find this helps deliver air to the coals in the rear, keeping them burnt down better. Pushing it out the front worked good for me, I don't take responsibility if you chose to try it, this is nearly what worked for me. I will snap some pictures when I go to fire next to help people understand what I'm talking about.

[theguywiththename]

115171151811519
In one image you will see the 2 channels I was talking about. In the image of the side and boil, you may be able to see that the boil begins at the point where the back of the firebox, outlined by the weld marks. the other image shows the weld marks clearer. You notice I'm running this as a batch for operator ease. I find somehow the ribs act like flues. It usually boils more aggressively but it needed more wood in the box.

[dwyerja]

Great I think I can make that change on mine to experiment. Thanks for the pictures.

[brass maple]

It looks like you could raise your fire up higher, which in turn would make the front of the pan boil better.

[dwyerja]

Well i was able to use firebricks to raise the fire up and that helped a lot. When the season is over i think changing the draft locations will help even more. Thanks for your input!

[mellondome]

Split your wood smaller. Looks like you are using house stove wood. Wrist size.