I never posted pictures of my home built gas/electric hybrid over here.

I was looking for folks input on the size of the input and exhaust dampers.

I started building it long before I found this forum.

The inside dimensions are 18" X 26" X 40 the input and exhaust are 3 inch stainless tube with cast iron dampers.

The location of the input is on the lowest point on the front door.

The exhaust is mounted on the back side at the top center

I will post pics of my next project that I want to try a reverse flow vertical.

Nicklemore that is one dang nice verticle hot n cold smoker , ya done good :thumb::thumb::thumb: gotta pass out some poi-nts

I was looking for folks input on the size of the input and exhaust dampers.


How does it cook?

Any problems keeping the gas burner lit when you are using it?

Looks good from here. :thumb:

Dave

Looks Like a Nice Unit From Here...:thumb::thumb::thumb:

Great job!! :thumb: :thumb:

Ya sure done a nice job...:thumb:

The biggest issue I have is lack of pressure on the burner, I have built a guard around it to shield it a little more.

It was getting blow out just by closing the door or a slight breeze through the damper.

I have tried all sorts of burners and regulators, even a complete setup off a GOSM but all had the same result.

I was wondering if I may be "using" all the oxygen in the box and extinguishing the flame. I don't really think this is the case, but I figure I would run it past every one.

I think it is more of a propane pressure problem than anything else.

I have another burner off a camp stove that I may try, the holes on the burner are real small, and I think that will create more pressure at the flame.

It is well insulated, recovery time is pretty quick.

I have it set up that I can swap the burner assembly and replace it with an electric element.

I have the element hooked into a PID for low and slow snack sticks and sausage.

I also want to build a lump basket and give that a whirl.

not sure what to tell you about your problems but you did a nice job on the build

I am no expert, but it looks to me as if you may need to add a vertical section of pipe to the exhaust. That will help create a draft, beleive it or not, it could be starving for oxygen. Also, if you control the air going in, you don't need a damper on the exhaust. This calculator was a huge help when I built mine. http://webpages.charter.net/tomchism/BBQ%20CALC%20Forms/BBQ%20Smoker%20Calculators.htm

I never posted pictures of my home built gas/electric hybrid over here.

I thought these pics looked familiar, and now I know why. That's one heckuva smoker:thumb:
http://www.smoked-meat.com/forum/showpost.php?p=42618&postcount=9

First off Nice build man!:thumb:
Try a snorkle for your burner. You may have to experiment with diameter of pipe. but you are definately starving your burner. run a small tube from outside right up under or next to the burner. It will draw the O2 it needs, especially after it warms up. Start small and work up to the max temp you want to run. Can't quote formulas or computer programs, just my 2 cents

I was wondering if I may be "using" all the oxygen in the box and extinguishing the flame. I don't really think this is the case, but I figure I would run it past every one.

it could be starving for oxygen.

It can happen. When I put the propane burner in my SnP it used to snuff out -- even if the burner was running pretty hard doing chicken at 350°. Turns out I had the tuning plates so close together that the unit could not hardly get a draft through it. I took one of the plates out and widened the gaps between the remaining plates and -- presto -- no more flame going out even when it is running low.

So yeah, a bit of extra draft can really help a propane burner. Actually, I would think you could run the intake and exhaust wide open anytime you are using propane or electric as the draft does not affect temp unless you are burning fuel.

Unless you are trying to "hold heat in" with the exhaust but I never really worried about that. If I needed higher temp using propane I just turned it up some more.

Dave

I found that I have to run both of mine wide open just for "flow"

I figure it would be hard to get creosote issues if I had good flow with my home made smoke gernerator.

I think I will play around with some deflector plates inside the damper to deflect air off of the burner.

A smaller burner may help as well.

this is going to sound like a stupid question, but are you sure that you are using a propane burner, rather than NG? just want to verify as that could be a possible issue.

as far as it going out, i'm not sure. if the flame goes out on it's own when a breeze comes through, it sounds like a draft issue. do you have a picture of the interior side of the intake? i'll have think about this a bit more. when it comes to furnace flues, there are times where they can be too short, or too long, but on a furncae, we are talking about much higher BTU ratings. i'm sure flue length would affect your smoker too, but the questions is "who much will it affect it?"

Later,
Andy

Thanks RP , these pics are when the build was first done, since then, I have added 3 foot of alum. duct with a 90 out the back to aid in draft.

I usually only use the damper when I am starting out and want to load up on heavy smoke, or sometimes when using an electric element I try to balance it out for smoke/temp.

The burner has the the mixture tube running to the outside of the unit where the valve and the orifice are mounted.

Thanks for everyones opinion, I will take a look at the link RP.

also, do you have any closer pictures of the burner? depending on the design, as the CO2 falls, it may be snuffing out the flame as it fills up that dish. if it were me, i would probably take that bowl off, or at least drill some holes in it to help with that.

Later,
Andy

Here is a pic of the burner and the valve

i have replace the burner with a setup from a GOSM, but I have to run it so low to keep temps in check there is not a lot of pressure on the burner.

I have to run it so low to keep temps in check there is not a lot of pressure on the burner.

i still think there is something else going on here. think about a water heater pilot light... minimal pressure for energy efficiency, but it stays lit unless the gas is cut off...

Thats sort of what is puzzling,

I can almost blow the flame out, and it will go out if I close the door too fast.

If I close the door real slow and pay attention and have both dampers wide open, its OK. I am using a in-line valve to control the flame as well.

I am still thinking I have too big of a burner for the box...as insulated as it is, it would not take too much to keep it heated once it is up to temp.

that is a possibility. the burner seems pretty small, but when you really think about it, that little flame is consuming a lot of oxygen.

it is somewhat unlikely, but still a possibility that your quick-closing of the door is causing the flame to burn too lean and extinguish itself. thus, your theory of not enough pressure. have you tried cranking the burner up, then shutting the door? i assume your extinguishing issue is only at low temps?