First Build Info Gathering

[jarjarchef]

New to this forum. I am going to build a RF smoker this year. It will be a marathon to say the least.

Welding: experience me (none), Father In-Law (25+ years) At this time we will be using a stick welder. We are looking for a mig or tig at this time for his shop.

Main Tank: Propane (76”L x 24”D approx.) 150 gal I think. Not going to be mounted to a trailer at this time.

Questions/Opinions:

Firebox location: Side or center? I see pros and cons to both. I am leaning towards the center, like the heat efficiency of all the heat going into the cooking chamber and less fuel usage.

Fire box to cooking chamber baffles: Are they needed? Have not seen much information on this in either way. Seen in some, but not on other builds.

Reverse Flow Plate: a solid sheet with a drain or a split one with a drain rail in the center. I am leaning toward the split, so it can be removed for easier pressure washing if ever needed.

RFP end gap: I have seen a couple builds that have had the gap at the end being adjustable. The only thing I have seen is to make sure you have at least the same size as the firebox opening. Just looks like another way for smoke to leak and unnecessary fab work.

Propane: I have seen some of the builds use propane burners in the cook chamber and the fire box. Is it really needed?

Smoke Stack: I understand the need for it to be the same diameter as the hole for the firebox, so you don’t have any air flow restriction. But why does the length matter?

I am sure I will find more questions, but this is a start.

Thank You to those before me that have posted all the great builds and advice. You have already helped me answer many questions and given me so many design ideas.

 

[pops6927]

Thank you, Jarjarchef for your post!  Several stickbuiders will be along I am sure to answer your questions.  In the meantime, however, stop into Roll Call and say hello and allow us the opportunity to introduce ourselves and welcome you to the forum!  Thank you again for logging on!

 

[SmokinAl]

Like Pops says there are a bunch of very talented builders on here to help you with your build.

Welcome to SMF, I think you found the right place to hang out.

 

[solaryellow]

New to this forum. I am going to build a RF smoker this year. It will be a marathon to say the least.


Welding: experience me (none), Father In-Law (25+ years) At this time we will be using a stick welder. We are looking for a mig or tig at this time for his shop.


Main Tank: Propane (76”L x 24”D approx.) 150 gal I think. Not going to be mounted to a trailer at this time.



Questions/Opinions:


Firebox location: Side or center? I see pros and cons to both. I am leaning towards the center, like the heat efficiency of all the heat going into the cooking chamber and less fuel usage.



Fire box to cooking chamber baffles: Are they needed? Have not seen much information on this in either way. Seen in some, but not on other builds.



Reverse Flow Plate: a solid sheet with a drain or a split one with a drain rail in the center. I am leaning toward the split, so it can be removed for easier pressure washing if ever needed.



RFP end gap: I have seen a couple builds that have had the gap at the end being adjustable. The only thing I have seen is to make sure you have at least the same size as the firebox opening. Just looks like another way for smoke to leak and unnecessary fab work.



Propane: I have seen some of the builds use propane burners in the cook chamber and the fire box. Is it really needed?



Smoke Stack: I understand the need for it to be the same diameter as the hole for the firebox, so you don’t have any air flow restriction. But why does the length matter?



I am sure I will find more questions, but this is a start.



Thank You to those before me that have posted all the great builds and advice. You have already helped me answer many questions and given me so many design ideas.

Placement of the firebox is up to you.

Do you mean damper instead of baffle? If so it isn't necessary but might be nice to have.

If you do decide to put it on a trailer make sure you have a way to secure the RF plate during transport.

Propane is not necessary but could be a sleep saver during long cooks.

The diameter of the chimney isn't as important as the volume. The height correlates to the draft. Make sure to use the pit building calculator and you will be fine.

Sent from my DROID BIONIC using Tapatalk

 

[clyde79]

im looking for a good answer on the damper between the two chambers also as of now im leaning towards not and just using a plate as a baffle. i could build the damper easily but not have seen the benefit other than heat control,which i could do with fire size and air intake, i could be wrong hopefully someone comes along and posts the theory behind it. good luck on your build

 

[solaryellow]

im looking for a good answer on the damper between the two chambers also as of now im leaning towards not and just using a plate as a baffle. i could build the damper easily but not have seen the benefit other than heat control,which i could do with fire size and air intake, i could be wrong hopefully someone comes along and posts the theory behind it. good luck on your build

You have nailed it. The other benefit would be choking off the firebox quickly for whatever reason. It isn't necessary but might be a nice to have for someone.

 

[sunman76]

I put a damper between the firebox and cook chamber on mine but hardly ever use it because I put damper on my chimney also.  I can leave the chimney damper open and close the firebox off and cool done pretty fast is things get a little hot.  So it is there if I need it

 

[jarjarchef]

So it would appear that my father-in-law has a trailer frame for the tank already. So if we do a stationary smoker it will be a center fire box and if we decide to mount on the trailer (if it is worth fixing up after about 10 years of sitting) we will do an offset firebox with a vertical smoker above the fire box. So now we are going to dig them both out of where they are sitting behind a ton of old stuff. Would be nice if we could get the tractor in the area where they are, but that would be too easy! Then we can look at both together and figure out the next step. Now I need to find my Q pics and figure out how and where to post them. 

 

[dragons breath]

Hey jarjarchef, I'm a newby at this stuff but I have just finished a center fire reverse flow. Only one fire up at this point but the center ran about 25 degrees hotter than the sides. I did put in a damper between firebox and smoke chamber but left it full open during initial burn. It got late and I went in the house after a few hours.

I'm defrosting a turkey and will try closing down the damper a little to see if that helps even out the temps. If it does help you might want to put one in yours for the control. 

 

[jarjarchef]

So I went to this web site (http://www.feldoncentral.com/bbqcalculator.html) to run some numbers through it to see what i am looking at for fire box size and chimney pipe length. I ran into ahead scratch-er for me, sometimes i get wrapped too much in details of the numbers. When it gave me the length of the chimney it was 21" for a 6" diameter. So two questions: Should I have used ISD or OSD for the pipe? Does the length count the portion that is inside of the cook chamber? I am planning on putting the intake for the chimney close to cooking grate level, it has worked very well for me on the mod I did on my CG Outlaw?

 

[jarjarchef]

Hey jarjarchef, I'm a newby at this stuff but I have just finished a center fire reverse flow. Only one fire up at this point but the center ran about 25 degrees hotter than the sides. I did put in a damper between firebox and smoke chamber but left it full open during initial burn. It got late and I went in the house after a few hours.

I'm defrosting a turkey and will try closing down the damper a little to see if that helps even out the temps. If it does help you might want to put one in yours for the control. 

 I purchased for my work location a Vertical Water Smoker last year. It was very well put together. I had not used a vertical water smoker of this quality before and had to do several burns to get it figured out. I could put 5# of charcoal to start it up and then add a couple sticks of split oak to it and it would hold at 300F wide open for a couple hours. We would choke it down a bit below 1/2 way when we loaded it. It would hold at 225-250F with no issues for 3-4 hrs. I ran it on a cold day for Florida (40F) and had to open it up just a bit. The only time we got very big heat spikes is when the water pan dried out. Lets say I figured out why a back draft is a bad thing!!! I was thinking of either running a water pan on top of the RF Plate or a deflector plate between the RF Plate and fire box baffles to help with the added heat in the center, sort of like a heat shield.

 

[solaryellow]

So I went to this web site (http://www.feldoncentral.com/bbqcalculator.html) to run some numbers through it to see what i am looking at for fire box size and chimney pipe length. I ran into ahead scratch-er for me, sometimes i get wrapped too much in details of the numbers. When it gave me the length of the chimney it was 21" for a 6" diameter. So two questions: Should I have used ISD or OSD for the pipe? Does the length count the portion that is inside of the cook chamber? I am planning on putting the intake for the chimney close to cooking grate level, it has worked very well for me on the mod I did on my CG Outlaw?

To be honest with you, sinking the chimney to grate level on a reverse flow really isn't needed. The RF plate will provide plenty of convection for cooking. If you were building an offset SFB it would be a different story.

 

[jarjarchef]

So a brief update. We are not using the tank. We have a pipe that is 30"diameter and will be approx 7' long. This has turned into a much bigger build then planned...... And that is not really a bad thing. We are adding 2 burners, wood storage basket, 2 burners in the cook chamber, 2 mounts for propane, mount for spare tire and if possible a table top work station. Yep a lot of stuff.


Where I need help is the trailer size and design stuff. The trailer has me concerned because it is only 8' at this time. We can add some length with the tongue, but how much is safe and what should I look at to make sure we are road safe?

We will not be building much for the next month or so do to surgery (not me). But we will be designing and gathering the materials to push the build to be done ASAP.

Any suggestions on this build is very welcome. If it is built! I can cook on it and make magic thin blue smoke.......

 

[solaryellow]

So a brief update. We are not using the tank. We have a pipe that is 30"diameter and will be approx 7' long. This has turned into a much bigger build then planned...... And that is not really a bad thing. We are adding 2 burners, wood storage basket, 2 burners in the cook chamber, 2 mounts for propane, mount for spare tire and if possible a table top work station. Yep a lot of stuff.


Where I need help is the trailer size and design stuff. The trailer has me concerned because it is only 8' at this time. We can add some length with the tongue, but how much is safe and what should I look at to make sure we are road safe?

We will not be building much for the next month or so do to surgery (not me). But we will be designing and gathering the materials to push the build to be done ASAP.

Any suggestions on this build is very welcome. If it is built! I can cook on it and make magic thin blue smoke.......

Our trailer is a work in progress as well. Knowing that it would change as time went on, we kept the axles separate from the frame of the trailer and used u-bolts to marry the two. This has allowed us to adjust the position of the axles. Ideally, you want a 60/40 split of weight where the 60% of weight is in front of the trailer axles toward the vehicle. You also want to make sure you can adjust the tongue weight. Too much or too little tongue weight will greatly affect the way the trailer tows and ultimately safety. Other than DOT, local laws, and tow rig limitations, the art in trailer building is about balancing the weight properly.

 

[JckDanls 07]

Length is not as much as a concern as weight is... The axle is rated for a certain weight and that will determine how big you can go.. now 2 axles will double your weight restriction...

 

[jarjarchef]

So got some new questions. Running the numbers through the calculator and have a few grey areas. So here are what I am looking at and looking for some of your expert advice.

Cook chamber: 30"D x 84"L

Firebox: 27"W x 30"L x 30"H

Air inlet opening: 8 ea @ 3" x 4"

So here is the grey area for me. My RF plate is planned on 4" below the grate on the sides and 6" below the grate in the center/drain channel. I am guessing that the width will be 27"W at the low point. So how do I figure the opening? I am guessing that it is approx 150" sq opening. But the calculator says it should be 190ish. So any way to increase the opening or am I good?

The other area is the smoke stack/chimney . I plan on trying to find 5" pipe. The calculator says 62" long. So if I put 2ea 5" stacks can I cut the height down to 36"? Or would I be better off trying to fabricate a rectangular stack based on the volume needed?

Thank you for all of your time and advice.

on a side note:
Since I have never welded before I am going to do a small project of a vertical gas smoker. I figure if I have ugly welds they will not be seen by many people.

 

[jarjarchef]

Been a bit since I posted here last. Busy at work. I was planning on doing a major part of this build next week out of work and no kids. However I have just trashed my knee at work, so the build may be delayed a bit.

On the good side my father in law just got a Millermatic 210 mig welder for his shop. Trade for some work he did for someone.

I am looking for a good place to find some scrap piles to pick from. If anyone has some suggestions please let me know. I live just off of I4 between Orlando and Lakeland Florida. I was just going to buy a couple sheets and be done with it, but since I have a week and not able to do much I figure I can look around.