500 gallon fattie build

[Remy Bernabela]

Hi guys,

I got a 500 gallon fattie model for free. So let's build a smoker I'd say. I searched other threads and found these numbers from Dave Omak in post number 8 in the link below.

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http://smokingmeatforums.com/index.php?threads/500-gallon-rf-build-revised.243153/
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Same volume but not the same dimensions as mine looks like a short 1000 gallon. My tank measures 59.75" between the welds. And the end caps are about 21 to 22 inches deep like on a 1000 gallon. I guess the diameter should be 41" or 42". The tanks is already filled with water, so can not be moved to measure it good until I cut out the door in january. The tank needs to sit there a couple of weeks as it smells propane all over the place.

Can I stick to the numbers above for a 500 gallon?
The plan is to build almost the same smoker as him. He says it's working perfect so why dramatically change it? The only difference is the tank itself and the limitation to 36 inches on the width of the FB to fit between the springs of the axle I have (also free). It's a Toyota rear axle. 37 " between the springs and 42" eye to eye. I want the firebox to sit in between to keep the center of gravity as low as possible.

Here is my feldons
Link to BBQ Pit Calculator

My wishes are:
- 3 grates. I do a lot of ribs and they take a lot of space.
- single door. Staying 2" from both welds gives me about 55" of grate width which I do not
want to split even further and lose more space.
- Even spacing between grates. For taller meats I can remove the top (smaller grate). I do
mostly (beef)ribs, butterfly chickens, briskets etc. Flat meats.

Top cut of the door.
I'm thinking 8 inches from the centreline. I will be 1.5 inch from the inside diameter straight down from the centerline according to the circle calculator. S

Bottom cut of the door
14" from the bottom inside diameter. With the RF plate at 11" I'll have a roomy 3" between RF plate and bottom lower grate. But whatever gives me more cooking space. I want functionality first. Meaning I can insert the firebox as far as needed to lower the RF plate.

Firebox
Here the steel plates are 100x200 cm. So if I make the FB 100 cm deep and insert it an inch past the weld in the straight of the tank it will spare me a few cuts and maximize the use of material.
The height would be limited to 33" to have enough ground clearance using 15" wheels with regular tires.
36
The box would then be 33"H x 36"W x 39.5"L. But at 14" segment height the RF plate would be 39" wide. So I can't just cut out a 90 degree section out.

What ya'll think about copying the numbers?

 

[Remy Bernabela]

Stoked already!!!

 

[ahumadora]

think about flippin it upside down so you don't have to fill the valves in.There should be only 1 to fill in the bottom. You can cut the feet off it and reuse them. Make sure the seam weld is on the back side and not halfway through your door. check out my article how to cut a tank.

 

[Remy Bernabela]

I'm not really concerned about plugging the valves. The bottom one is a 2" one which is perfect for a drain. I want to use the valve openings to integrate the doorstops. Just a matching pipe with a 90 degree bend which will hold the doors.

And I want to restore and keep the tag plate. It's a piece of history and it may be seen. The tank is only from '88. But after 50 years it will tell more. The top cut will clear the tag plate easily.

I will look at your article (if I can find it). But I'm going in eith a 7" grinder to give me a smoother cutline. I don't have a plasma cutter. Time isn't an issue neither. I just want it to be done right. And I'm not gonna paint it. I like it like this.

Any suggestions on the firebox size? I think 36" wide to fit between the springs will be just fine. And having a 1.5" gap between CC and FB in the CC on both sides.

 

[ahumadora]

https://www.smokingmeatforums.com/threads/how-to-cut-doors-on-a-smoker.266455/#post-1737225

 

[Remy Bernabela]

Will these numbers work for me? My tank is 40 or 41 inches in diameter. I think 40. Going to measure it today. The dam height is 12". My firebox will be 1 meter (39-something") and half of it will be sunk into the cookchamber an inch into the straight. With the tank being shorter also I guess 12" should be just fine. I can't find any rule on that. But I looked at some builds here where they went 2" lower because of that. And I still lean towards 1 single door and counterweight. I love the looks of them. Between the welds is 59.75" and I want every square inch I can get. That's the reason I need a bigger smoker.

I plan to cut the door out (not completely) tomorrow. I want the "legs" of the counterweight to keep the door from warping when cut out completely.

Thank you in advance.

 

[ahumadora]

Here's my 2 cents.
Is your bottom grate going to be fixed and below the cut line for the door?
3" is barely sufficient between your bottom grate and the RF plate. From your drawing you show the bottom cutout at 15"...That is 5" below the center line on the tank. I would move it up to 3-4" below the center line for a 1 meter diameter tank. If you are going for maximum space, use a heavier gauge angle for the racks but reduce the size of the angle to 1". For the counterweight legs to help stop the door from warping you will need to weld them the entire curve of the door . ( 1" stitch weld every 3-4") If it is going to warp it will warp, no matter what. You top grate does not have much space, so think about lowering it. For more space you can weld in expanded metal into the end cap of the tank where the smoke makes the turn. It just won't be removable and will be a hot area. post some pics of the counter weights.

 

[Remy Bernabela]

Bottom grate will slide out IF possible. But maximum space and functionality are priority. The middle shelf will be as large as possible, so if the lower can slide out I can access the meat in the back. Otherwise the middle has to be narrower and I have to reach over it to reach the lower back.

By raising the bottom cut by 2 inches (and lower grate too I suppose), I create 5 inch of space between RF plate and bottom of the lower grate. Right? Which means the lower grate doesn't slide out anymore. Really not concerned about door weight. I'll just make beefier counterweights.:mad:

I will use 40mm (1.5") x 6mm (0.25") angle iron for rails and grates. That is what I can buy here in curacao. Smaller sizes are only 2 mm thick. The top grate can be used for leg quarters sweet potatoes etc. and should be an addition to the other two.

I do a lot off ribs and leg quarters. here I'm 1 of maybe 5 who does a brisket once in a while. So flat meats and stuffed and rolled meat is what I do the most. No whole hogs (yet). That's why I need maximum space and thought this exta wide tank can give me three grates.

Gracias por tu ayuda señor!!!

 

[Remy Bernabela]

I came up and marked the following for cutting next week. All from centreline.

Top cut door. 25 cm
Bottom cut door. 82 cm
Firebox cutout 102 cm and 1 inch inside of the welds.
Grates 140 cm wide when leaving 2" inside the welds.

Eyeballing it from a few steps back looks good. Tank measures 41 inch outside diameter.

 

[ahumadora]

Looks good. If you are using counter weights you can reduce the top cut to 20cm and still be fine. You made a good decision posting here and asking BEFORE cutting. Many folks start cutting up the tank then come here asking how to do it after making errors.

 

[forkin pork]

I'd say you got a good mind for this build, and I think your gonna do just find. I've built a few cookers in my days and just from winging it, they all worker great, so you be fine, and don't get yourself all confused with input overload.
My first thought was the feldons calculator, so stick with those numbers and do great.
Good luck, keep us all posted with pics too.

 

[Remy Bernabela]

Looks good. If you are using counter weights you can reduce the top cut to 20cm and still be fine. You made a good decision posting here and asking BEFORE cutting. Many folks start cutting up the tank then come here asking how to do it after making errors.

Thanks guys. I'm just a type of measuring 100 x and be 100% confident before I start something (based on what I know at that time). I started with a Weber kettle in march and build this one with my dad in july. It works, but has some major flaws which will be addressed when the new one is done. Quite a growth in just a few months and now I'm really in need of more capacity. This exploded so fast I can barely keep on with the demand. I don't have time to go back and sort things out later. Carnaval period is on the way etc.

I'll move the top cut back to 20 cm. Cut it partially next week. Put hinges on with bolts so the door can be removed for whatever reason in the future. Drain the tank empty and roll it over to cut the FB opening. Then move the tank to the welder. and the rest should be good. Firebox will be 100 cm deep and wide. and is future proof for a warming cabinet. Smokestack is 8" ID. I have 2 meters of pipe to play with. I ordered a 3500 lbs 60" (spring centre) axle and expect it within 2 weeks just in time to make the trailer and finish the rig. Next week I'll start for real!!!:D


Doors on the wrong side. (grates above RF opening)
FB to small (20%)
FB/CC opening to small

Spacing is 3.5", 3.5", 6" and 6.5"

Overloaded on the first catering job for 60 persons. Ribs and chicken legs. I knew right away I needed something much bigger. But had to win back the costs of this one and earn for the new one.

Last week's cook. 14 picnics at once. I did about 50 throughout the whole week. A bbq job for 60 and catered a christmas dinner.

 

[forkin pork]

Wow sweet job!

 

[Remy Bernabela]

GOT IT NOW!!!

This is it. The final layout. Minor adjustment to the door.
- Top cut moves up from 25 to 20 cm as suggested (I use counterweight).
- Bottom cut is 3 cm lower for slide out bottom grate. But still leaves me with 4"
above the RF plate,
- I'll have 18.5 inches above the bottom grate which I configured to my current
smoker which has a good spacing for what I cook.

Lower and mid grates will be the ones heavy and loaded and so will be 40 mm 6 mm thick angle iron. The top grate will do mainly side orders (corn potatoes etc.) and doesn't have to carry as much weight. It will be 40x20 mm 3 mm thick. It will be on on the flat side.
Tomorrow I re-mark the door and Wednesday I cut! I'm very confident now and expect this to be a very good cooker.

Happy new year.

 

[ahumadora]

Nice going. Looking forward to see more pics. Don't be afraid to roll the tank around when cutting out the door to make it easier using the 9" grinder. be sure to stay 90* to the tank when cutting.

 

[Remy Bernabela]

Yes sir. The tank has been sitting with water and soap for three weeks. I'm really not concerned about explosions now. I'll cut the top cut and somewhere down the side cuts to drain about half of the water. I can also reach the cap on the bottom now to drain more if needed until I can roll it over to continue the cut.

 

[Remy Bernabela]

Well. I'm still alive!!! It went buttersmooth. Really. I left about 2" on the top and bottom cut until the hinges are in place. Also the half moon which goes underneath is cut and the tank warped there. But that doesn't matter for the build. So I'm about 95% sure that the door won't warp anymore. The stress is already released. If that's true I'll document how I did it. Maybe it will help someone else.

Yesterday I bought 3 pieces of 2000x1000x8mm steelplate
3 lengths of 50x100 rectangle tubing
1 lenght of 50x6mm strip for door flange

Next step.
Transport the tank to the welder (5 minutes trip).
Fabricate hinges and weld them on.
Start cutting the sheets for the firebox and make the vents.

 

[ahumadora]

looks good. Tubing is for the trailer chassis? The door will move a bit when you cut it fully open, they all do that. How are you going to cut the 5/16" plate?

 

[Remy Bernabela]

Yes. The 2x4 is for the trailer. Inside the welds is 59.75". I'll split that in 3 for 3 cross members which will be 6 legs. The tank being 3/8, the cross members so close to each other and the 6 legs and the firebox welded together should strengthen the trailer as a complete structure. 2x4 channel iron cost more than 200 dollars per 20 foot!!!

I'll work from outside in. So firebox will be welded to the tank first. Then the door comes of and we'll see what happens from there.

The plates I will now cut with the grinder. It really went smooth today! I used 3.5 cutting plates. And the fb will be 1000x1000x750mm tall. The best use of the 1000x2000mm plates. The rf plate is 987mm. So it makes sence.

 

[Remy Bernabela]

Today while smoking on the other pit, I went to the scrapyard and got me this piece of pipe for 25 bucks I guess. 52 kilograms, 60x8(id)x 1/4". I cut out a 8" high section to fit on the plenum. The plenum will be Franlin and FatStackSmokers style. 8" high, as wide as possible and will sit 1 inch lower than the bottom grate.

I also cut the hinges out of the same 5/16" plate. By double the hinge on both door and tank side they will be stronger than a 1/2" single configuration. And saves me a few bucks. I made 3 of these to support the calculated 95 kg door. I drilled 1/2 holes. Tomorrow I'll go and get the correct angle to sit them on the tank and make the final shape of them.

Monday I'm going to cut out the section for the plenum so I can get the radius of the dome to finalize the top and bottom plates for it. So next week I can really start building with all the major pieces being ready.