# RF smoker build

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#### 4a616b65

##### Newbie
Original poster
Hi, just joined and looking for a little advice on my numbers.

I’ve been at the same point for weeks with my builds as I’ve put off making a cut until I’m certain the numbers are right.

Decided to just ask and hopefully get a second opinion before I take the plunge.

So I work in metric usually so I made all my measurements in metric and converted to imperial rounding up to two decimal places.

It’s a cylinder with domed ends.

Internal dia. 460mm-18.11”
Length without ends. 1230mm-48.43”
Length with ends. 1430mm-56.3”

Smoke stack int dia. 94mm-3.7”
Smoke stack length 1005-39.57”

Firebox 500x640mm-19.69x25.2”

I was unsure on how to use the calculator for domed ends, which length I should of entered, so I calculated this using the volume of a cylinder using 48.43” length plus the volume of a sphere based on the 18.11” diameter and divided by 4.6 to end up with 13150.211cuin.

Then for FB/CC opening in square inches,
Area under the RF plate in square inches and Area required at the end of the RF plate in square inches (how would I calculate this? Calculate the segment area of the dome then a rectangle for the cylinder adjust that size until I get a distance from the peak of the dome?)
13150.211x0.004=52.60

Firebox volume-13150x0.33=4339.57

ESV I was a bit confused about the 0.017 bit if the answer was times this or not. So I have 13150.212x0.022=289.30x0.017=4.92

For the smoke stack I have an off cut of 4” about 39” long is 36” the ideal height above the cc?

I did the calcs 36x0.7854x3.7x3.7=387.07 does this mean my stack is too large in diameter? Can I shorten it to get the required value? Will a plenum be better than just into the top of the CC?

I calculated the cutout height from circle calc to be 4.67” this seems small had previously calculated about 6” and I was concerned once I’ve cut and welded it it isn’t easily altered.

RF plate width 15.845”

Apologies In advance I’m aware some of these will be asked over and over, I have searched through the forum and gone over these a few times think I’m just Making it worse for myself getting more confused.

Im yet to calculate the intake holes as I’ve got enough on with getting firebox fabricated and attached and the grates Rf plate smoke stack etc.

Last edited:
JLeonard
SmokinEdge
Yes sorry should have stated the numbers stated above are the calcs from that guide just not sure if I’ve done them correctly or like I said the throat is correct

So I happened to go on the laptop today on the website for the first time, turns out when I had been looking on my mobile it shows the page totally different, no strike through 0.017 and no old number next to it.

So anyway I took the plunge still not sure my volume calcs were right so if anyone could clarify that it would be great.

I’ve made the cut for the throat at 5” by time I have the 5mm steel from fire box should be somewhere near. Next step is to tack the firebox into shape and weld the firebox in.

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Bit of an update, I got everything welded up and useable, there still some finishing off to do (shelf, top grill, close up the gaps on the lid and firebox door)

I had a fire in it on Saturday afternoon and oiled it, then cooked beer can chicken on the night it turned out really tasty.

Whilst it cooked great I felt like I wasn’t really in control of the fire, I couldn’t get the temp over about 250’f, I was trying to get it as hot as possible for applying the oil.

It seemed to sit at 200 and be happy I could get it up for a short while by putting another log on maybe should have split them down a bit more. I got a free sack of unknown hardwood logs so I used them used the full sack which was usual feed sack sized 25kg bag sort of size which I thought was quite a bit and I had to sit tending the fire quite a bit so I think this is the next thing to look at.

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So had another day trying the smoker out, it went terribly, felt very defeated by the end of the day.

Set up around 7am, put a load of lump coal in and some bark kindling then some oak logs and the fire was roaring in no time left it to die down and cool off as it was over 300deg.

Started off with two briskets, never bought brisket before and these were totally different cuts to what I’ve seen in videos and after a bit of research it looks like the US cut is different to the UK cut? And it had a bit of a few day old smell to it. That’s was the first issue.

I put a pork joint on to make pulled pork, think this from the leg, this turned out ok but not as good as I had hoped, maybe I should of trimmed the skin and fat off or used shoulder, I think the internal temp should of got higher as I took it out at around 195. The fire hit a brick wall and everything wasn’t getting any hotter.

when I went to see my friend for the pork on morning he give me a full rack of ribs to try, these turned out not too bad either but I think I should of trimmed them down and took the belly off to do something separate with that.

Chicken was fine but again at the end I was struggling to get the internal temp up to where I wanted so I had to pop it in the oven for ten mins at end.

I think other than the cuts and trim of meat the biggest problem could be my fire? Do people usually have lots of constant flames in the firebox as mine I’ll put maybe two logs on at around 200’ and get the flames for a few minuets getting it up to around 220’ then they die right down and I’ll only have a few little flickering flames. I’ve attached a pic of what it looks like most of the time.

I got a bit fed up and stuck a load of logs on, learnt that lesson, lots of dirty smoke black bellowing out luckily only for a few minuets and something must of sunk in from videos somewhere after about 20 seconds I opened up the chamber door so there was minimal damage to the food, however in the panic I managed to melt my new thermapen so I was really pleased with myself after that. After five mins in the fridge it still works but the case is all melted.

all the food I felt didn’t turn out how it should of, wasn’t as tender and juicy as it should of, I put the pork joint and ribs and briskets on at 8am chicken on at 12:30, everything came off at around 16:30.

Was contemplating cutting it all up after yesterday but thought after sleeping on it I’d ask on here if anyone has any advice or tips.

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