Do you mean the throat or rf plate or both. I will try to measure tomorrow if i get time.AndrewPalmer71 wrote:On the old one, I bet the FB to CC dimensions are a bit small.
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Thanks, the old cc was a 47kg propane tank 43"*15" and the fb was a smaller gas tank (19kg i think) 24"*12" with rugby ball shaped throat 8"*5". Tha throat is at an angle to the bplate so there is a hot spot at that end, the stack is 4" diameter and 8" from the top of the cc, is was a lot longer before i cut about 14" off.Rodcrafter wrote:Very nice work on the door.
On the topic of the older build, It has been my experience that on an offset the FB needs to be tall enough to allow the wood burning fire to have the room it needs to burn correctly. I mean we know that most of the heat comes from the coal bed. But to make more coals from wood it takes very dry wood and small enough fire to burn thoroughly.
The next thing that comes to mind is it seems to have a better draft when the air doesn’t have to make too many turns. Example the air coming from the FB going through the throat with the opening placed where yours is has the air coming out of the throat at an angle then moving across the baffle plate. I would be willing to guess there’s a very hot spot on the FB end.
Gizmo was working on determining the temperature in the FB and under the BP to compare to the CC temperature. I say that to say each transition takes a toll on temperature. The same as turbulence in air flow.
Ok I will drink my coffee now.
Making memories!
Thanks for the info, i have another couple of tanks so may cut the firebox off and fit another one vertically with a door on the front so i can have a taller fire. What do you think? But before that i will have to get the new one finished.Dirtytires wrote:I’m going to take a stab at this...
I ran the numbers and you are pretty close on firebox size. Your firebox is at 107% and normally I would feel that is fine but on a long horizontal firebox a much greater volume is taken up below the grate. And tho you probably just cooked with it, it also appears much of the space below the grate is full of ash further decreasing the volume. On that type of of a firebox, I might suggest switching to a lump charcoal instead of wood as it tends to burn cleaner and needs less volume (in my experience, at least). I might also experiment with keeping the fire to the far right and away from the cook chamber as much as possible. If you decide to go charcoal, you can use a basket and drop it a bit lower in the firebox as well.
The calculator indicates your throat should be about 21.71 inches but you indicated yours is a 5x8 oval making it approximately 31.5 sq inches. It is a bit big as is.
Chiminey is recommended at 10.75 inches long from top of the cook chamber for the 4 inch diameter you indicated.
Looks like a solid unit and should be able to get it much more user friendly with a couple of fixes.
Just my 2 cents here...
My new one is made from 8mm steel plate and is square, i have a sheet of 3mm steel which is the same thickness as a propane tank. What do you think about using 3mmDirtytires wrote:I’ve never liked tanks for fireboxes as they just don’t have the right shape. My feeling is that if you are going to cut it off, build a square one. Trust me, you’ll never go back to a tank.
By looking at the dimensions of the large propane tank what sort of size firebox wood i be looking at including space for an ash pan.Dirtytires wrote:Again, just my opinion here but I would use 3 mm (roughly 1/8 inch) to make a square box over a tank every time.
With that said, many would consider it too thin and wouldn’t touch it. Much depends on how hot your fire is, how often you use it, where you store it and how often you clean it. My first smoker was a bolt together from a box made from even thinner material. I used it for almost 10 years and still have it. The key was I never left ash in the firebox and it was never stored unprotected from rain. Take care of it and it will last you a long time.
So, thicker is always better but I would say you are just fine with 3mm.