Rectangular RF Smoker, first build

[lowlandssmoker]

Hi all,

I've been working on the design of my first smoker build. Due to availability of materials, it will be a rectangular design made out of sheet metal and a square tube frame.

This is my first attempt at it, please tell me what you think of the design so far:

[Rodcrafter]

I like it. Looks pretty challenging but very cool.


Making memories!

[Dirtytires]

With the slide out racks, really not a reason to have the whole top open. A single door design would allow less heat to escape, be easier to seal and much easier to build.

The general feeling is that top mounted exhaust stacks are preferred. Some have the side/low mount but you will be happier with it on top.

What was your reason for the single high mounted vent on the firebox? Most will tell you that the air vents should be at or below the fire level.

Overall, it’s a cool concept. You are going to have a lot of work ahead of you.

[Big T]

That's a cool design with a few issues as mentioned above but they could be straightened out before you finalize the design. I don't know if you heard but Frank finally finished the plans for MACK which is built using plate steel, it's a tried and true design if you wanted to take the guess work out of it.

[lowlandssmoker]

With the slide out racks, really not a reason to have the whole top open. A single door design would allow less heat to escape, be easier to seal and much easier to build.

The general feeling is that top mounted exhaust stacks are preferred. Some have the side/low mount but you will be happier with it on top.

What was your reason for the single high mounted vent on the firebox? Most will tell you that the air vents should be at or below the fire level.

Overall, it’s a cool concept. You are going to have a lot of work ahead of you.

Thanks for your help

The reason the stack plenum is lower down is to force the hot air to move down from the CC 'roof', in an attempt to even out the heat between top and bottom racks. I understand this will cause some reduction in total airflow, but the RF channel is extra tall to compensate. This is definitely a prototype, based on ideas from every corner of the internet... The next one will take all the new lessons learned into account

The reason for the smaller intake, higher up on the FB is to allow an increase in overall airflow without restricting the fire. It adds cold air which helps keep the CC temperature down without deriving the fire of oxygen, needed for TBS. Well, that's the theory anyway

[Dirtytires]

Have you tested these theories? A smoker is a huge commitment of time and money. I’ve got hundreds of hours and over $2k in materials and I would have been pretty upset if my smoker had not performed properly. At the end of the day, you cannot change the laws of heat transfer and airflow.

Not saying you are not onto the next great idea but be careful and research it before you dump time and money into a new concept.

[lowlandssmoker]

Have you tested these theories? A smoker is a huge commitment of time and money. I’ve got hundreds of hours and over $2k in materials and I would have been pretty upset if my smoker had not performed properly. At the end of the day, you cannot change the laws of heat transfer and airflow.

Not saying you are not onto the next great idea but be careful and research it before you dump time and money into a new concept.

I've not tested them personally; as the title states this is my first build. I have seen quite a few smokers around the interwebs utilize these design concepts which reportedly work very well.

At the end of the day, if it doesn't work it's all just steel... nothing that can't be fixed with a plasma cutter and a MIG welder

[ajfoxy]

Lowlandssmoker said:

At the end of the day, if it doesn't work it's all just steel... nothing that can't be fixed with a plasma cutter and a MIG welder

Yep, I've so the same outlook. Try it, if it does not work, fix it or turn it into something else.

[Dirtytires]

Looks like you are jumping in with both feet and you’re eyes wide open. Have to admit, that is a great way to start. Good luck and keep us informed on your build as it progresses.

[Hydrant]

That looks like it will be one heck of a smoker! Pics of the build please!

[Squiggle]

Looks a lot like "Mack". Definitely keep the doors to just the front.

[lowlandssmoker]

First bit of welding practice happened last Saturday:


Might not be the prettiest piece, but it's got some strength at least:


Also practiced on some square tubing:


First uphill weld didn't go so well:


Last night I cut the square tubing for the firebox frame, which I'll hopefully start welding tonight.

All comments are welcome

[ajfoxy]

I've seen and done a lot worse beads than those.

As the saying goes... practice makes perfect. By the time you finish this project you'll b good to go... for the next one.

[lowlandssmoker]

Thanks, that's encouraging

So they look to be fine as they are?

[Big T]

They appear to be fine, it looks like both pieces of metal got hot so there should be good penetration. You can clean up the welds with a grinder if you don't like the way it looks but there's nothing you can do if there's no penetration except re-weld it. Just keep reminding yourself that you're building a smoker not an sculpture so you can get by with an ugly weld as long as it will hold and like AJ said, you'll get better as you go along.

[mp4]

Don't beat yourself up trying to weld uphill either. There's nothing in a smoker that would require it and it's much easier to weld downhill.

[lowlandssmoker]

Thanks guys, much appreciated

Some more practice and progress from last night:


Apologies for the large pic, I'd hoped to be able to resize it after uploading, but that doesn't appear to work...

[Dirtytires]

Good start...slow and steady from there.

I realize that just because you took the picture where you did does not mean you welded there but I’ll mention this only because you are new to welding. That styrofoam, if that is what it is, is considered flammable and really is not safe to be welding around. A spark from the welder or grinder could really ruin your day.

[lowlandssmoker]

Hmm, I have been grinding and welding right next to it, and despite my 'best efforts' it hasn't caught fire. I believe it may be a fire retardant version, I'll be sure to check. Thanks for the advice! I do have an extinguisher in the room in case anything does happen, too

Last night's progress, the firebox frame is now finished (aside from grinding down some of the welds):

[lowlandssmoker]

It came out mostly straight, only 2 corners warped by a few millimeters... nothing a 3 ton jack and a big hammer couldn't fix

[ajfoxy]

Looking good.
Trust me, by the time you are finished with this smoker you'll be an expert at grinding. And using tube you'll also be pretty nifty at filling holes. Both "skills" are not bad things as they will give you confidence to fix any raised beads and holes caused by burning through the tube on occasions.

[Dirtytires]

A “few mm” is “straight” in my book.

[Rodcrafter]

Oh yeah


Making memories!

[lowlandssmoker]

More progress today! Went to the steel shop and bought most of the materials needed to complete the smoker:



Spent the rest of the afternoon with the plasma cutter:



Next up: finish the cooking chamber frame!

[lowlandssmoker]

Well, skip ahead a number of steps... the summer was very hot, definitely not suited to being in overalls all day, so the project stalled for a long time.
We recently got back to it, and managed to finish it just before the end of the year!

It looks just like the CAD version, except we mirrored it side-to-side because it would fit the yard better:





We fired it straight up:



We have smoke! (neither thin nor blue just yet, it was still heating up at this stage)



Couldn't resist putting some meat on there:



Quite impressed with the smoke ring on the fatty:




The smoker really ran beautifully straight away. It was 41F outside, it took about an hour to fully heat up to around 225F. With the addition of two small oak splits every 40 minutes and some pre-lit charcoal every 90 minutes or so, it maintained a beautiful 225-250F for around 5 hours.
I am especially pleased with this result, since neither of us had ever operated a smoker before. If us two newbies can do it, it must mean it was built well

Thanks to everyone on here that helped make this project a success, either by offering advice or recording your endless knowledge on this wonderful forum!