Help requierd with design please

[TerryEspo]

Good Morning Everybody !!

Well, idle hands are the work of the devil. I cant tap due to severe freezing weather so I started another project. I want to build a small arch to fit a pan I have. I will build the arch around my pan.

I just wonder if there is a mathamatical science behind the size of the firebox? The length of the slant and the end where the stack sits ?

I took a pic with my phone, poor image, but should be enough to work with. My questions are what my demensions should be.

My pan is 55" long, but only 18" wide. The arch will be 74" long. I picture it in my mind as three sections, fire box, slant part and stack end part. I have a paper cut out in the picture and hope someone can adjust my measurements.

Right now (with paper) my firebox is 28 length, slant part is 27" long and stack end is 19" long. The slant section goes from 12" down to 6".

I may have to get a better picture if that is too confusing.6435

Also, what should the depth be at the stack end, I,m thinking like 6" deep. If you look close I have the sections numbered 1,2 and 3.

Please let me know if I need to tell you anymore info.

Thank-you. Terry

[HyeOnMaple]

Looks good, light it up!

[TerryEspo]

Here is a pic with digital camera, maybe better than my phone pic. 6439

Hope to hear that my dementions are acceptable. I do intend on useing fire bricks too. Maybe that will effect the rear 6" height and maybe I need more room than that ? As the smoke goes out toward the chimney, how far along do the bricks go? All the way on the slant I,m sure,, but still asking ??

Thanks.

Terry

[psparr]

Just my 0.02 cents. Make the box bigger and the ramp lower and if you need to you can always shorten things up with vermiculite or blanket to get it to where you want it. If the box is too small or the ramp too high you would have to do a lot more work to fix it.

[Mike R.]

My firebox it 2' x 2.5' including the grating and draft. My arch is 5 1/2 feet long made for a 2'x4' pan. My taper goes from 6" at the back to 1 1/2 feet where it joins the fire box.

I haven't welded mine up yet, but have the plans for it. If I knew how scan them onto the computer I would.

I'll try later tonight or tomorrow after my exam.

[psparr]

The height of the ramp at the back of the arch depends on the stack size 6 inch stack, you'd want about 1inch under the pan. 8 inch, about 1-1/2 inches. That depth equals the square inches of the stack. Anything less and you restrict the fire, anything more and your wasting heat.

[TerryEspo]

Thanks PS,,,thats the kind of science I want to learn.

Makes great sense about too much or too little space at the rear pipe location. I appreciate that tip.

I guess this smaller arch is a fun little project but really a practice on how to build a good arch when I finally get a good flue pan. Someday......

Terry

[ACollette]

Terry,

I agree with PSParr. Build the arch to the specs of the drop flue pan that you hope to have, not the flat pan that you have today. You need to account for the space occupied by arch board, brick, or blanket in area #2. It is easy to fill in the space with more insulation as he describes. Best of luck.