Propane conversion

[bobmws]

Hey guys, propane newbie here. I have a Masterbuilt electric smoker that went tits up after 6 years with a power issue. Decided to convert it to propane using an unused side burner from a grill, the frugal approach! The electric box is well insulated, and so I cut a 3x6 vent (sliding damper) on the bottom opposite side of the top vent thinking that fresh air would help cool/adjust things. After 5 minutes the temp with the burner on low was at 330 and climbing!

I saw a post using the needle valves to lower the gas flow, and also about blocking holes in the burner with screws. I added the screws to the burner and got a needle valve in the gas feed line. I also cut a 4" diameter hole in the top, just need to get a dryer vent pipe for the new hole.

Now after a brief test I was able to hold the temp ~160 degrees steady. This with the bottom fresh air vent still closed! I'm thinking if I open the bottom vent a bit I can run a bit higher flame and avoid flame out. I'll experiment more when I get the ventpipe installed.

Now my question, chips or chunks? Wet or dry?

 

[daveomak]

Install a flame out sensor.....

Man killed when meat smoker explodes

Colleen Kottke, The (Fond du Lac, Wis.) Reporter 4:49 p.m. EST December 15, 2014

(Photo: The (Fond du Lac, Wis.) Reporter)

TOWN of LAMARTINE, Wis. — A Wisconsin man using a homemade meat smoker to cook turkeys and chickens died when the smoker exploded, police said.

Richard L. Zabel, 55, was found dead Saturday afternoon inside a machine shed.

"The North Fond du Lac Ambulance and Lamartine first responders were called to the scene for the initial report that someone had fallen," said Lt. Cameron McGee of the Fond du Lac County Sheriff's Office. "When investigators arrived on scene, they discovered that a 55-year-old man was dead inside the building."

Zabel, a town of Lamartine man, did not live at the building's location, but lived nearby.

"Evidence indicates that the flame on the LP burner went out and as a result the gas continued to accumulate inside the smoker," McGee said. "And when (Zabel) went to relight the burner, the spark from the lighter caused the gas to explode."

McGee said the force of the explosion caused the heavy duty door of the smoker to blow open, striking Zabel in the head, killing him instantly.

"When something explodes, it's going to blow open at the weakest point which was the door, which was triple-latched," McGee said.

McGee said the smoker was larger and better constructed than most store-bought models.

"It was about 4-feet tall and about 3-feet wide and built really solid, including the door. Someone really put a lot of thought into building this thing," McGee said. "We were told that they had been using it for the past three years without any problems."

The Fond du Lac County Sheriff's Office is investigating the incident.

 

[cliff43j]

Dave, one could say that he went out smokin' ;-)

 

[bobmws]

 
Install a flame out sensor.....

Man killed when meat smoker explodes

....snipped.....

Interesting info Dave, thanks.

No luck in finding said sensor, but I will pay attention.

I did get a vent pipe to fill the 4" top vent, so the insulating foam can't potentially melt.

Now with the fresh air vent fully open, I can keep about a 1/2" flame burning and maintain ~165 degrees with little fear of the fire going out. 210-220 degrees has a healthy 3/4 " flame.

If it happens to be exceptionally windy I'll baffle the fresh air inlet with some cement blocks.

Now Chunks or chips? Wet or dry?

I presume chunks will stay smoking for a longer time frame, negating the need to replenish.

I'm using an old 6" stainless pan on the burner, saw some references to using Lava rock for even heat. Yes or No?

Gonna do some pork loin on Sunday!

 

[daveomak]

Flame....   if you need to elevate the pan, go ahead...

 

[g dog]

I think what Dave is referring to as a flame out sensor is a thermocouple and shut off valve.  When I built my propane smoker I used one like this:

https://www.ebarnett.com/Sku/116018...lL6MGrej-UUPdApXKSmZqZqBGCFdyQ6bU4aAqta8P8HAQ

All you need to do  is to install this after your needle valve, probably right next to your burner, and run the thermocouple out of the end of the valve and have it sit in the flame of your burner.  When the flame goes out, it will shut the valve off so it doesn't become a nice little bomb next to your house. It may be a little bit of messing around to get it right, but I think the peace of mind is worth it. I think the valve with the fittings and thermocouple would cost you about $30, max.

Also, chunks burn much longer. 

 

[daveomak]

Thanks much g dog.....    pts...

 

[bobmws]

 
I think what Dave is referring to as a flame out sensor is a thermocouple and shut off valve.  When I built my propane smoker I used one like this:

https://www.ebarnett.com/Sku/116018...lL6MGrej-UUPdApXKSmZqZqBGCFdyQ6bU4aAqta8P8HAQ

All you need to do  is to install this after your needle valve, probably right next to your burner, and run the thermocouple out of the end of the valve and have it sit in the flame of your burner.  When the flame goes out, it will shut the valve off so it doesn't become a nice little bomb next to your house. It may be a little bit of messing around to get it right, but I think the peace of mind is worth it. I think the valve with the fittings and thermocouple would cost you about $30, max.

Also, chunks burn much longer. 

Good link, thanks g dog. 

I looked at the valve & thermocouples. If I understand the operation, the thermocouple would have to be in a flame and brought to temperature in order to light the burner.

This would eliminate my piezo igniter, not a big deal, and require manual lighting, correct?

 

[daveomak]

Yes you have to "pre heat" the flame out sensor, as you do on an RV hot water tank, OR you can install a pilot flame that burns continuously.....

Pilot flame.jpg

• daveomak
• Jan 29, 2017

 

[g dog]

As Dave said, yes you do have to heat the thermocouple to keep gas flowing. The valve with the link has a button on one end that you hold in while you let it heat up. It takes about 30 seconds. I think you could still use your piezo igniter, in fact that would be a really nice set up if you put the valve close to the button for your igniter. That way you could just push the gas valve button, then the igniter and light it remotely. That would be a pretty sweet set up. Just get a long enough thermocouple. The standing pilot is a good way to go but much involved and way more $$$$ to set it up safely.

 

[g dog]

This set up, with that valve and thermocouple is really easy to do, and works great. I had one installed on my burner initially and I tested it a few times and it did the job well. I then switched to a whole standing pilot valve with a temperature controller and while it works well, it cost way more and can be very finicky at times. Probably because it is mounted to my smokehouse and is outside 365 days a year.

 

[bobmws]

So far I have smoked a pork loin and some ribs since the conversion and everything has come out great. I'm able to control the temp with no problem, and no issue with the flame blowing out.

I do find that the water tray uses more water with the propane heat, this may be adding to the moistness we have noticed, along with a crisper bark, maybe more even heating.

Between the water tray and the pan I use for the wood, no drippings are fouling the burner!

I did build a baffle for the fresh air entry, and that along with the 'tray' the burner sits in keeps the flame from wavering, even at very low levels.

Here are a few pics.

SM1.JPG

• bobmws
• Feb 11, 2017

Burner control & needle valve.

SM2.JPG

• bobmws
• Feb 11, 2017

Smoke outlets

SM3.JPG

• bobmws
• Feb 11, 2017

Burner sourced from a grill. You can see the insulation of the body at the fresh air inlet.

SM4.JPG

• bobmws
• Feb 11, 2017

SM5.JPG

• bobmws
• Feb 11, 2017

Fresh air inlet baffle, upside down for pic.

Comments and suggestions welcome.  

 

[g dog]

Nice! I really like the baffle idea. i don't use a water tray, I've tried it but I think it actually impeded the smoke flavor getting into the meat so I quit. Like you are already doing though, I'd always keep some physical barrier between the open flame and the meat that absolutely keeps grease from hitting that flame. Even if you have to add some tin foil to cover possible areas the grease might get past. Otherwise prepare to find your smoker in a giant ball of flame with a melted propane line burning like a blow torch. Don't ask me how I know.

 

[cliff43j]

Now that is a really neat conversion!  I may have to start looking into this more closely.  It would appear that you have solved all of the problems.  Question:  How much smoking time do you get on a 20# tank of propane and at what temperatures?  Also, what is the BTU rating for your burner?

Thanks,

Cliff.

 

[tardissmoker]

Did you put the thermocouple and shutoff valve on? If so, I missed it in the pictures. If not, you still have a bomb waiting to happen! Guess I'll avoid Florida for a while. You could be labelled a terrorist bombmaker!

 

[bobmws]

Nice! I really like the baffle idea. i don't use a water tray, I've tried it but I think it actually impeded the smoke flavor getting into the meat so I quit. Like you are already doing though, I'd always keep some physical barrier between the open flame and the meat that absolutely keeps grease from hitting that flame. Even if you have to add some tin foil to cover possible areas the grease might get past. Otherwise prepare to find your smoker in a giant ball of flame with a melted propane line burning like a blow torch. Don't ask me how I know.

g dog, so far so good, the water tray has caught 98% just a tiny bit has hit the pan I put the wood in.

 
Now that is a really neat conversion!  I may have to start looking into this more closely.  It would appear that you have solved all of the problems.  Question:  How much smoking time do you get on a 20# tank of propane and at what temperatures?  Also, what is the BTU rating for your burner?

Thanks,

Cliff.

Cliff, I have no idea what the actual burner rating is,but all o fthe grill side burners appear to be rated at 10,000 BTU.  Only used it twice, don't know how much I'll get from a tank, but with the needle valve installed, it is a much smaller amount than the normal side burner valve passes.

Did you put the thermocouple and shutoff valve on? If so, I missed it in the pictures. If not, you still have a bomb waiting to happen! Guess I'll avoid Florida for a while. You could be labelled a terrorist bombmaker!

Not as yet! Watch the NASA reports for a sun flare in Central Florida!