It has begun

[ribwizzard]

And yes, on a 120 gallon tank, a 4 x 8 sheet should be enough. You can go with 24" tall firebox, but it really only needs to be 18" or 20" deep.

 

[mrspooky]

Don't forget fresh water to wash your hands! 2nd most important feature , propane is first.

Is the water usually gravity fed, or pumped?

 

[ribwizzard]

You can get a nice water tank from Nothern tools for around $30.00 or so, they are sprayer tanks but approved for drinking water. If you mount it high enough, just plumb in a valve somewhere handy.

smoker2.jpg

• ribwizzard
• Sep 19, 2012

smoker4.jpg

• ribwizzard
• Sep 19, 2012

 

[ribwizzard]

See the valve? Under the foil pan right where the spray bottle is hanging

 

[mrspooky]

10/4. So you got the tank on the back side of the cooker? does it get too hot there? about how far would you want to keep the water tank from the cooker?

 thanks

 

[ribwizzard]

Just a few inches really,

On my current build, I'm thinking of using some 8" PVC, installing it right under the serving rack/ shelf, but spraying it with black truck bed liner material first, so it will blend in with the black cooker.

Trick is, always put a cap full of bleach in the water when you fill the tank, this will keep it from growing any fungus or anything, and that tiny amount of bleach you won't tell is even there.

 

[mrspooky]

I got the tank on the trailer..... What a P.I.T.A. I don't have any hoists, lifts, extra person or even a big tree to hoist the smoker on the trailer after its finished so I figured that I could get it on the trailer and work from there. Im guessing that it would be easier jacking up a fire box to the cooker than to get it all put together and try putting it on the trailer. All Ill need to do is tack the FB on and roll the cooker over so I don't gotta be working upside down. That tank was heavy enough as it was by myself.  Ill probably end up sliding the tank forward about 12"- 16" and cut the back of the trailer off and adjust the axle accordingly.  Im glad I didn't score a 250 gal or Id never got it on there.

 Thanks for lookin

 Spooky

20140330_170536.jpg

• mrspooky
• Mar 30, 2014

 

[mrspooky]

20140331_131332.jpg

• mrspooky
• Mar 31, 2014

I have a question about location of FB/CC hole. Nothing here is to scale and the numbers a fictitious. If the calculator said I needed a 20" wide opening (#1) I assume that you would find the center of that (10") , make a mark and draw a arch. The distance between the two is 6". Now jumping to diagram #2, if I was to put a straight edge on the bottom of the tank and measure up 6" (A) would that be where you would make your horizontal cut as shown in #3? Also on diagram #2 how far do you know to cut into the tank (B)? Im assuming just far enough back to get past the rounded end. Is my logic right here?
Thanks

 

[mrspooky]

OK, scratch all that previous crap ^^^^^^^^. I had to call in the educated one of the bunch (wife). Diggin through threads, and the 2 different calculators, we have everything figured out except for one thing.  There's going to be 3.75" from the RF plate to the cook surface, Is  that  ok?

 Thanks

 spook

 

[lendecatural]

Did she use the circle calculator? http://www.1728.org/circsect.htm

I've seen 4-6 inches as a good rule of thumb but it isn't stated as part of Feldon's chamber calculator. You should be good since you have almost 4".

 

[mrspooky]

Yes.  The tank measurements are:

 Diameter 24"

 Radius    12"

 FIRE BOX

 H 24"

 W 24"               124.7% size differential

 L 20"

 Area of FB to CC opening

 92.16

  92.16 X1.5 = 138.24

 So that gives us 6.25" (+/-) height  X  21" length for the FB/ CC opening.  From what we gathered, the volume needed for the RF plate set it at  8.25". This put the RF plate 2" above the CC/FB opening. This only left 3.75" from the RF plate to the center (radius) of the CC.

     ***** In the circle calculator we erred on the "high side" of figures ************ 

 Does this sound right?

 Thanks

 

[lendecatural]

http://feldoncentral.com/bbqcalcula....78&fi=3,1.5,0,27.72,6.16&fc=9.70,13.72,73.92

There is a problem with Feldon's since it is all based on the cook chamber size. If you leave a larger firebox than is required in the calculator, it will inflate the size of the opening into the cook chamber. Where you got 92.16, the actual requirement is 73.92. Most people make it a little bigger and raise the RF plate some along with adding additional size (1.5) where the air has to make the turn at the end of the RF plate. If you cut up from the bottom of the tank 5 1/2 inches it results in an area of 78.2", bigger than needed and if you go to 6", it will be half way between the bottom of the tank and the center line so you could put your grates at the 3 o'clock position and have six inches between your RF plate and the grate. Does that make sense?

Circle Calculator.png

• lendecatural
• Mar 31, 2014

 

[mrspooky]

Yea it does make sense. I just wish I hadent already cut the hole.......................................... JUST KIDDIN! Thanks for clearing that up. we'll rework and redraw plans tomorrow.
spooky

 

[daveomak]

MrSpooky, evening.... I have read and reread this thread..... what is the size of the tank you finally are building your pit out of..... Dave

 

[lendecatural]

Hi Dave,

It's hidden back in post 8, he wanted a 250, got what he thought was a 150, that turned out to be a 120...

I plugged a 120 into the Feldon's link pasted above, please give my calculations a double check before he pulls out the torch!

 

[mrspooky]

Good morning Dave. Yes it is a 120 gal tank. Sorry for the confusion.
Spooky

 

[daveomak]

120 gallon x 231 = 27720 cu. in. CC needs

9240 ci FB
471 ci stack
28 sq. in. FB air inlet .... can be split adding a second opening above the Fire Grate... improves temp control...
111 sq. in. FB/CC opening
111 sq. in. area under the RF plate

If the tank is 24" diameter then seg height of 7" will give 110 sq. in for the FB/CC opening and area under the RF plate... and Chord AB figures the RF plate width of about 21 3/4"


73.92" is a Feldon number and I figure 1.5 X that makes for better air flow and solves the overheated FB that some folks experience... and better and more even temps in the CC..... soooo ... 73.92 x 1.5 = 110.88 sq. in.....

All of the numbers can be adjusted a bit.... making them too small will affect the performance of the smoker... and cause headaches for the operator.... or so it seems....

 

[mrspooky]

Thanks everybody for all the info. Im just trying to get all my ducks in a row before I mess anything up. I dont want to walk away with a substandard piece of equipment when there is all of this info to be had. Thanks again for the patients with me and walking me through it this far.
Jason

 

[mrspooky]

Nother question. Ill be getting the 1/4" for a firebox this Weekend. .. whats the best way to cut it? All I have is a 4" angle grinder,skill saw and a sawzall(sp?). Any tips would help!

 

[daveomak]

Have the supplier shear it.... if it's possible...