275 oil tank on a trailer build

[Rufus T. Doofus]

I'm very happy with the way the CC doors seal up. I'm not sure if I'll need to add a gasket of some sort in the vertical seam between the two doors. I should know this weekend if that area needs attention. Before applying the sealer I cleaned the area with a wire brush and a degreaser. Rinsed it with water. Wiped it down with muriatic acid to neutralize the rust. And then a cleaning with acetone. I hope this is clean enough to make the gaskets stick well for a long time.

I'm planning to fire it up for the first time Friday or Saturday to burn out all the crud. I should finish the FB tomorrow.

I haven't mounted the temp gauges in the CC doors yet. It seems, from looking at photos, most builders generally place them about midway vertically in their CC. Is this the ideal location? Or is there a better place to mount them?

I have a new axle and springs on order. Should be here in a week or so.

[Squiggle]

Most people mount them in the middle, but that's usually for round tanks, my suggestion would be to put one just above the top shelf & one between the bottom two shelves in each door (probably overkill but I'm like that, lol).

[Rodcrafter]

In my experience the gauges become a quick reference only because I use digital thermos to really monitor the temps and I put them right next to what I'm cooking. I would and do just go mid space.


Making memories.

[Rufus T. Doofus]

In my experience the gauges become a quick reference only because I use digital thermos to really monitor the temps and I put them right next to what I'm cooking.

I have been researching which digital to get. Do you have a recommendation?

[Elgine]

This is the digital I use and works very reliable and I don't have to be by the cooker to check maveric et-732 redi-check

[Rodcrafter]

Yep that's the one I use too. They have a new one called ET-733 but I don't have that one. I have 2 of the others and a cyber Q which is great too.


Making memories.

[Elgine]

Yep I have 2 also, and decided it's time to learn to weld and make the pit of my dreams

[Rufus T. Doofus]

Looking at most of the digital wireless thermometers most appear to have fairly short probe leads. 40" on some of them. My cooking racks are 50" long. I assume you can't place the transmitter too close to the steel cook chamber. So I'd likely end up with maybe 30" of probe inside the cooker if they enter the chamber at the end end opposite the FB. Or maybe I should plan to bring the probes in from the top above the doors?

[Elgine]

I know you can buy leads for the maveric that are 6' long, I've got a set when I ordered my Mavericks

[Pete Mazz]

Me too!

https://www.amazon.com/6-Foot-Replaceme ... +probe+732

[Rufus T. Doofus]

Thanks for the suggestions on the Maverick. I ordered two of the 733s and two of the 6 ft long probes. This will make it so much easier to learn how this smoker works (or doesn't work). I'm one of those kinds of people that prefers data vs. cooking by 'feel'.

[Elgine]

Glad we could help, I love data myself, something else that was suggested to me was keeping a log of temps during cooks so you have a reference like, how you built the fire, where it settled at, when you add wood how mucheach time you add. To help plan for future cooks

[Rufus T. Doofus]

I think I will do a paper log or something along those lines initially. After I know what I want to record I'll likely design my own Tappaque-like device using an Arduino and/or Raspberry Pi. I designed an interface and wrote some code for doing remote data logging of the Triangle Tube boilers in some rental properties I own. I think I could do something similar for the smoker. Welding and metal fab is just a hobby. I was a computer engineer for 15 years before semi-retirement in the woods of Maine.

[Elgine]

Welding is going to be a hobby for me as well, I'm a trucker who stays out working way too much. Usually 3 months then come home and take 7 to 10 days off

[Rufus T. Doofus]

I fired it up for the first time today. Mixed results. It was up to 225 degrees in 1 hour and 275 degrees at the 2 hour point. I wanted to check the amount of fuel burned but couldn't open the FB door. Oops. It expanded so much that it was snug in the opening. So I have some work to do there.

[Squiggle]

Doh, bummer dude!!

[Rodcrafter]

I know you didn't want to have to do it but it is only steel you can fix it.


Sent from my iPhone using Tapatalk

[Rufus T. Doofus]

FWIW the air ducting seems to work well. The charcoal and wood burned completely with a much smaller amount of ash than I would have expected. I'll need to vacuum out the duct holes with a shop vac from time to time since a little of the stuff gets in there.

How hot should I be able to get the CC? It made it to 275 and stayed there for a little over 2 hours with the door stuck shut. I was burning a combination of dried maple splits and some old charcoal briquettes that I had laying around and have no use for. That's certainly high enough for smoking but I would have expected it to get a bit hotter. Ambient temps were about 50-52 degrees when I was testing it.

[Rufus T. Doofus]

And my problem with the door sticking closed was to be expected had I thought about it. I used some strips of 1/8" thick steel and pop rivets to hold the tadpole door gaskets in place. I had a 3/8" gap around the door prior to adding the gasket+steel+rivet head. Now the gap is about 1/8" to 3/16", apparently not enough at temperature. The odd thing is that the only side that seems to be a problem is the latch side of the door. Like the door primarily expanded in one direction away from the hinges.

I'll fix it today after the rain stops and try again. I was really hoping to get the CC up to at least 350F for 8 hours to cook the years of fuel storage out of it.

[Rufus T. Doofus]

Fixed the stuck door problem today. I should have looked up the coefficient of thermal expansion for mild steel and planned accordingly.

I've been running it wide open for the past 4 hours on chunk charcoal. The hottest I can get the CC is 310 degrees. That should be enough for anything I would ever want to do but I was kinda expecting higher. Maybe my duct system doesn't allow enough airflow for high BTU outputs?

Tomorrow I'll play with trying to control the cooking temps and smoke output.

This forum has been so helpful throughout the process of building this thing. I hope someone finds this topic helpful in the future. I'll post more pictures soon. Hope to paint it in the next week or so before it gets too cold.

Do folks generally season the CC and cooking racks with lard or something along those lines? Is it necessary/recommended?

[Big T]

I spray everything inside the CC with a light coat of vegetable oil and let it cook for a few hours, some guys throw some fatty meat on the racks also. You can open the door on the FB and see if the temp jumps up pretty high and that'll let you know if there's a problem with your intakes.

[Squiggle]

Sounds awesome dude!!

Most people usually coat the inside & shelves with a can of spray oil & get the smoker up around 300-350 for a couple of hours to season it, that's what I did with mine & it worked perfectly.

[Rufus T. Doofus]

I've got almost 8 quarts of rendered lard in the freezer. I'm going to try using that for seasoning. I'll warm it up to soften a bit and then smear it on everything in the CC. Should smell nice

I realized today that my first two burns were done with the tongue of the trailer 2.5" lower than level. This could be part of the reason I couldn't get it any higher than 310 degrees. The BTUs weren't moving smoothly out of the FB into the CC. I also hadn't finished mounting the CC racks and there were 4 holes (3/8" dia.) in the CC walls waiting for bolts. I don't know if these holes would have been enough to effect the smoker's draft but they could have played a part in lower temps. I've corrected these issues and am doing one more test burn now.

[Rufus T. Doofus]

First cook is scheduled for tomorrow morning. Going to try some pork shanks and goat legs.

I did an 8 hour burn yesterday. After a little trial and error I was able to keep the temps between 220 and 245 on both thermometers. There's a 5 to 10 degree difference between the two. My Maverick should be here today so I can get some better data with today's test burn.

Frank's video in this topic was a big help to me: viewtopic.php?f=11&t=775

This is what worked for me:
Startup: wide open vents with 2 chimneys of charcoal. 15 minutes later added a 3rd chimney.

At about 45 mins, the themometer closest to the FB to read 200 (30 mins after the 3rd chimney of charcoal). I added 1 small split piece of maple and closed the vents down.

The fueling schedule that ended up working best for me was every 30 mins or so I would alternate between adding 2 small/medium splits or add 1 chimney of charcoal and one split. Seemed to work well for me. I did get some white smoke when loading splits. I need to test preheating them on top of the FB. But for most of the day the smoker worked exactly as I hoped it would. Sitting level made a big difference. I burned 1 big bag of Royal Oak charcoal and maybe 8 splits. (didn't count the splits.) So the fuel consumption seemed reasonable too.

My air source holes under the FB basket do collect some ash. I may need to add 2 more holes if I want to do any 12+ hour cooking. I think at that point they would have accumulated enough ash that it would start limiting air flow.

I was really surprised how far I had to close down the intakes. I had 1 completely closed and the other open about 1.5". That's about 4.5sq" of opening for combustion air. Maybe my FB door is leaking. Hard to tell. I did test the draft with a match and it seems to be really drawing strong. The intake snuffed out the matchstick flame almost instantly.

My BP gap is set at 5.5". That's the area that the calculator said to use. It seems perfect. I used a 10" wide movable piece of 1/4" steel at that end of the CC. I may end up just welding it solid at some point. I'll take some measurements of the inside dimensions of the FB later today to. That way if people stumble on this topic in the future the info might be helpful for them.

[Big T]

I usually preheat my splits or leave the FB door cracked open until the wood flames up and then close the door. It takes a few runs to figure out what works best but it sounds like you're on the right path. Don't forget to post some pics of the Q when you get done.