2nd Build - Tank Offset Trailer Build

Horizontal smokers with a side firebox and tuning plates.
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dacolson
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2nd Build - Tank Offset Trailer Build

Post by dacolson » May 14th, 2020, 7:24 pm

After lots of consideration and some help from you all - thanks Big T - I’ve decided on building a standard offset with the 3 tanks and trailer I picked up. The plan is to shorten the 80 gallon tank to 44” by cutting one end off to use as the firebox. That leaves me with about a 60 gallon tank and a 20 gallon firebox, rough and tough.

The 2nd tank I have is a 30 gallon tank which will become a vertical smoker/warming chamber on top of the firebox. It will have baffles between the FB and the WC as well as a baffle between theFB and the CC. I haven’t decided I will also have a baffle between the CC and the WC, adding tuning plates to allow it to convert it into a reverse flow. TBD. A little mystery for me till I get that far.

The 3rd tank is 20 gallons and will become a charcoal grill sitting behind the smoker on the trailer.

Here are the tanks and trailer:
Image
80 gallon tank

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30 gallon tank

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20 gallon tank

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Trailer on the way home.

Tonight, I made the first cuts and mocked up the overlap on the CC/FB. Gonna have to research the calculators to get the right overlap.

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First cut - about 18” off the end.

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Mock up of the rough overlap

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Saw someone else on this forum used castors under the tank to allow for easy positioning. Works awesome.

I’ve got some 1/4” plate to cap off the ends. Will work on that this weekend.

Once it’s done, I might have to get the whole thing sandblasted. ntjones just painted their smoker w clear coat high temp. Love that look.

I’ll try and post a drawing of the plans soon.

More to come.


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Re: 2nd Build - Tank Offset Trailer Build

Post by Big T » May 14th, 2020, 9:43 pm

It sounds like you've got it all figured out... well sort of figured out =)) Good luck!! I'm sure you'll end up with a nice rig when you get it finished.


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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 14th, 2020, 10:09 pm

If I don’t like it, it’s alright. I have a weld eraser ...
E7D9E9A7-4D88-44BD-872F-87FE6FAA3296.jpeg
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Re: 2nd Build - Tank Offset Trailer Build

Post by Dirtytires » May 15th, 2020, 12:05 am

Nice....lol



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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 15th, 2020, 10:32 am

Question on the CC/FB throat calculation. The calculator for overlapping tanks shows an option for sizing with a dam between the CC and the FB but the calculator does not differentiate or show what adding a dam adds to the size of the overall throat. For example, based on my calculations, I need a throat that is 13" wide and 4.8" tall. If I add a dam - say 2" high at the bottom, do I just add 2" to the 4.8" height? New specs would be 13" wide by 6.8" tall including the 2" dam at the bottom? Here are the outputs of the calculators:
Screen Shot 2020-05-15 at 10.25.06 AM.png
Pit Calculator output
Screen Shot 2020-05-15 at 10.26.18 AM.png
Throat Calculator output for overlapping tanks

Also, I've read there is a maximum FB size somewhere. Mine is currently 125% of the minimum. Should I cut it back a couple inches to get closer to the calculator? I'd like the extra length for room to attach vertical warming chamber.
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Re: 2nd Build - Tank Offset Trailer Build

Post by Dirtytires » May 15th, 2020, 11:27 am

I believe you are using the wrong throat calculator. The proper one is entitled ‘throat calculator for overlapping cylindrical tanks.’ If you enter the 20 inch dia for both the cook chamber and firebox diameter, the 42.73 cubic inch throat and the requested 2 inch dam the results are as follows: height=5.976inch, width=14.25 inch.

And yes, I would decrease your firebox size. If you want to keep the length, consider putting a false bottom in the firebox.



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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 15th, 2020, 11:33 am

Dirtytires wrote:
May 15th, 2020, 11:27 am
I believe you are using the wrong throat calculator. The proper one is entitled ‘throat calculator for overlapping cylindrical tanks.’ If you enter the 20 inch dia for both the cook chamber and firebox diameter, the 42.73 cubic inch throat and the requested 2 inch dam the results are as follows: height=5.976inch, width=14.25 inch.

And yes, I would decrease your firebox size. If you want to keep the length, consider putting a false bottom in the firebox.
Thank you Dirtytires. I totally missed the dam height field. I had the right calculator, I'm just blind and left it blank. I get the same outputs now.

The false bottom is a good call also. Great idea. Might be a good way to integrate a removable ash pan. Good stuff sir. :beer:


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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 15th, 2020, 1:31 pm

I can maths! Minor adjustment to the throat calc using ID measurement of 19.625” yielding a height of 6” and width of 14.125”

Better yet, both ends can come out of one sheet. It’s a good day.

Image


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Last edited by dacolson on May 15th, 2020, 9:49 pm, edited 1 time in total.


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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 15th, 2020, 9:23 pm

A little more work before I shut it down tonight. I wanted to see how the end cap lined up w the CC as I suspected it sprung when I cut it. Sure enough, egg shaped. Went to work with the jack and chain and tacked around the edges till it all line up. Didn’t make for the smoothest welds with so many tacks but she held and everything is straight.

Image

Image

Image

Image

Image

The last shot is just a mock up of the cap for the end of the firebox. Feeling good about the start.


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Re: 2nd Build - Tank Offset Trailer Build

Post by Big T » May 15th, 2020, 10:25 pm

You're definitely off to a great start!! :kewl: I know that you mentioned a grease dam in an earlier post but I can't tell from the picture if there's a lip left.


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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 15th, 2020, 11:22 pm

Ya. I kind of forgot about it in my excitement of fitting both end caps onto my one piece of 1/4”. That will be an add on I’m afraid. Would have been cleaner to leave it part of the cut. I just have to remember to do it before I attach the firebox.
Last edited by dacolson on May 15th, 2020, 11:31 pm, edited 1 time in total.


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Re: 2nd Build - Tank Offset Trailer Build

Post by Dirtytires » May 15th, 2020, 11:27 pm

No one will ever know once the two get joined......and we won’t tell!



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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 15th, 2020, 11:32 pm

Haha. Thx DT. Another reminder to slow down, measure twice and cut 3 times. I think I read that somewhere.


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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 16th, 2020, 2:14 pm

Got an early jump today and mounted the fire box to the CC. Came out decent. Thought I’d spray arc the joint on the top. Didn’t turn out that great on the up hill. Thought I could get away with a slight incline but no dice. Started grinding it out to lay a normal bead but I’m out of discs. Have to run to the HW store. Maybe I’ll change my mind between now and then.

Image
Capped the FB and added the grease dam back in.

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Shot of the spray arc. Started grinding it even but I may just grind it out and start over.

Image
Side shot. I’ll use the plug on top of the FB as part of the baffle for the WC.


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Re: 2nd Build - Tank Offset Trailer Build

Post by hogaboomer » May 16th, 2020, 2:49 pm

You should have run it downhill.



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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 16th, 2020, 3:54 pm

Thanks hogaboomer. The tank is on a roller. If I grind it out, I’ll reposition the tank and give that a shot.


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Re: 2nd Build - Tank Offset Trailer Build

Post by ntjones » May 16th, 2020, 4:54 pm

I like that it says sears. That looks pretty cool.


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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 16th, 2020, 6:17 pm

ntjones wrote:
May 16th, 2020, 4:54 pm
I like that it says sears. That looks pretty cool.


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Me too. Trying to keep that and the specs label intact. I think Sears will burn off when I fire it up though.


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Re: 2nd Build - Tank Offset Trailer Build

Post by hogaboomer » May 16th, 2020, 6:38 pm

dacolson wrote:
May 16th, 2020, 3:54 pm
Thanks hogaboomer. The tank is on a roller. If I grind it out, I’ll reposition the tank and give that a shot.
Pretty sure you will like the outcome. What gas are you running for the spray?



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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 16th, 2020, 6:45 pm

Cheating. 80/20. Should be 95/5. Spatters some but I can usually run ok.


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Re: 2nd Build - Tank Offset Trailer Build

Post by hogaboomer » May 16th, 2020, 7:21 pm

I've run pulse spray before on a job with 90/10, but I haven't done it with my new machine at the house. All's I have at the moment is 75/25. Been itching to spray some on my new build, but I may just have to do it all short arc.

I did this 3 inch(may have been 4) rolled out going downhill.

Image



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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 16th, 2020, 7:30 pm

Looks awesome. I’m a hack. No way would mine look anything like that.


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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 16th, 2020, 7:31 pm

dacolson wrote:
May 16th, 2020, 6:45 pm
Cheating. 80/20. Should be 95/5. Spatters some but I can usually run ok.
Sorry - 75/25. Not 80/20.


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Re: 2nd Build - Tank Offset Trailer Build

Post by hogaboomer » May 16th, 2020, 8:03 pm

How hot did you run? I might have to give it a try.



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Re: 2nd Build - Tank Offset Trailer Build

Post by dacolson » May 16th, 2020, 8:25 pm

24 at 400. On 1/4”


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