Fire Box Build Help!

Fire box sounds about right. Maybe a tad on the large side based on ours. I think the 5" exhaust 62" long sounds way to long. I'll call my dad and ask him to run your math. He just went through all that on our reverse flow as we just redid the exhaust with a 20"x6" pipe and increased the nimber of air inlets. He will be more familiar than I on this topic.

Just a quick reply to help get you started. Use the search tool at the bottom of the page, enter "275 gallon" and you can start looking at a number of comparable builds. What is the shape of your tank, round or flat-sided oval and if the latter will it sit upright (flat sides vertical) or flat sides horizonlal? Do you have a picture, ideally in it's proper orientation? I'm on an iPhone but I'll try and check some of the math when I can get to a real computer.

Hey, I remember you getting this cooker and posting the clean-up. I'm not sure Feldon's formulas consider this shape cook chamber. If you look at the formulas in detail they infer either a cylindrical or rectangular configuration. Seems like a lot of folks who have actually built and cook on a 275 gallon "oval" in the upright configuration get by just fine with a 24"X24"X24" firebox. I'm also thinking 62"x5" exhaust seems excessive. The 5" or even 6" inch is good, but I'm finding it hard to imagine needing more than 24" height from the top of your cook chamber. Finally if you go with, for example, a 24" cube as a firebox, I would measure the location on the bottom curvature of the Cook chamber that is 24" (looks like about 6"-8" up from the bottom and make that the top of my opening to the firebox and the level of my RF baffle. I would rely more on the imperical results of folks that have this style cooker rather than the Feldon formulas. Hopefully a couple of the guys that have this style cooker will add some help.

This seems to work

Here is a picture of one I just finished with a fire box that is 30"x30"x30" offset fire box. There is a 1" air gap between the tank and the fire box and the heat tranfers hole (24"x5") that is filled in with angle iron. I did this to keep the oil tank away from the direct heat to maintain a more even smoker temp plus prolong the life of the tank. The fire box is made from 1/8" plate. the doors on the back can be opened seperately to avoid heat loss and the lid on top will make a great direct heat cooking surface...at least I hope I won't be using it for the first time til this coming weekend, I hope this helps.......