Shockingly Good Barbecue Smoker
June 27, 2012 5:14 PM   Subscribe

Jerry-rigging a hot plate. Help me (a total beginner at electricity) not get myself killed, and maybe even learn something.

Disclaimer: I'm a foodie, not an electrician (or even an apprentice).

So, inspired by Alton Brown's show on making a smoker out of a terra cotta pot and a hot plate, I set out to try it myself. To save a little money on the hot plate, I hit the thrift store, but the best I could find was an electric griddle, the kind with the "probe" type dial control that detaches from the unit for storage. The probe control is rated at 120v, 1500w.

Of course, when I got the griddle home, it was too wide to fit into the pot. So I figured if I could get the heating element out of another appliance (one that would fit), I could just attach it to the probe control from the griddle. Why let a complete lack of experience with anything electrical stop me, right?

I got the element out of an old rice steamer that looked like the perfect thing for the job. Just a circular hunk of metal with a steel coil running through it. Stamped on the element, though, was "120v, 350w."

So, first question: given the disparity in wattage ratings between these two things, can they be safely hooked together? Does the element only draw 350w, or does its lower rating mean it's wrong for use with a 1500w controller? Can I safely use this setup by keeping the controller on a low setting (Warm, 200F)?

Second question (assuming it's safe to try this): Given its role as a rice cooker, how much heat will the element generate? How hot do I want to set the controller dial to get the air in a large clay pot to about 250F?

I know I can easily buy any of the parts I need to do this over from scratch. I know I can save myself a lot of trouble by just buying an electric smoker. But I really want to make this work with what I have, partly just to see if I can do it (minor technical accomplishments are a big deal for me), and partly because if it works, I'll be done very soon-- I've got everything hooked up and ready to go, pending the OK from strangers on the Internet.

TL,DR: Is hooking a probe-type electric griddle heat control rated at 1500w to a heating element rated at 350w ridiculously dangerous and stupid, or will the element only draw 350w?
posted by Rykey to Home & Garden (11 answers total) 2 users marked this as a favorite
I think you'll burn out your element in short order. Really, don't do this.
posted by pompomtom at 5:21 PM on June 27, 2012

I am an electrician - but certainly not your electrician. I will tell you what you need to know - but I hope you are not planning to use this thing indoors, and I hope you have a fire safety plan in place when you do you use it.

The ratings on the "probe" and the element will work. If you think about electricity like a pipe of water, volts are the size of the pipe, watts are the water pressure (or flow volume) in the pipe. Your volts are the same, so they will work together (you can not connect a twelve inch water pipe to a two inch water pipe).

If the probe is over loaded, it will cease to function and burn. The probe can handle 1500w of water flow, after that amount the probe will catch fire. The heating element can produce 350w of water flow. Your probe could actually handle four of those heating elements (4x350=1400w)

I do not know about the cooking temperatures. But, I can tell you that the numbers on the probe will probably not accurately correspond to temperture. Those numbers were placed there to correspond to the heat produced by a different heating element. The probe is not a thermometer the can measure temperature. The probe is a switch - essentially a dimmer switch. If you have a dimmer light switch in your house, turn it half way down and the 100w bulb gives of 50w of light. But turn the same dimmer switch down on a 60w bulb, and now the half way point reading is producing 30w of light.

The heating element has a power cord that you plug in. You have to wire the switch into place in-between the power source (the plug) and the heating element. The "probe" is the switch, so it controls if and how much electricity flows from the power source to the element. You need to make good taps, and should be using wire-nuts, when you splice the probe into the heating element's power cord.
posted by Flood at 5:43 PM on June 27, 2012 [5 favorites]

I don't own an electric griddle and have never taken one apart. I'm not sure how the probe that's inserted into a griddle regulates the temperature vs desired temperature.

I'm assuming that it operates a switch/relay(whether purely mechanically or electrically) based on current temperature vs the desired set point. Also assuming that normal line voltage is applied to the heating element. If that's the case(which I am in no way sure that it is), and the rice cooker heating element is also ok to be used at the same voltage then you shouldn't hurt the rice cooker element by using the temperature probe as the driving "logic". This assumes that:

• The temperature probe makes good thermal contact with the element from the rice cooker. If good thermal contact is not made then the heating element will be over driven until it fails(bad) as the probe won't ever know it's at a high enough temperature.
• The power rating in watts for both heating elements is based on the same voltage being applied. Electrical power dissipated is directly proportional to heat generated, and is a function of the current running through the element and the voltage applied.

So if both of the heating element power ratings are at line voltage then the 1500W controller will easily handle the current needed to heat the 350W cooker element. However, if the heating element for the rice cooker was rated to dissipate 350W at 12V DC or something then the actual power dissipated at 120V would be much much higher and the controller would fail trying to provide the much higher current that the rice cooker element draws.That said I really doubt the rice cooker uses anything but 120V as a source for the heating element and really with a cheap multimeter you could check the resistance of the element and calculate the power that it should dissipate at your applied voltage. Nonetheless it is something to keep in mind and something that you should understand.

• I doubt that the actual temperature of the cooking surface will accurately reflect the dial temperature of the controller.

All of that said: Have fun but BE SAFE! Get a multimeter if you don't have one. Understand the basics of electronic circuits, your ground, neutral, and hot connections. You will be dealing with possibly deadly voltages. Don't leave any wires dangling about. All wires should be terminated properly and away from a place anyone can touch them.
posted by Quack at 6:04 PM on June 27, 2012

Woops, I meant to hit preview and come back as I had to run off. I see now that you wrote the rice cooker element is rated for 120v same as the griddle, so power ratings shouldnt be an issue.
posted by Quack at 6:41 PM on June 27, 2012

This is the sort of project that is reasonably straight forward but could hurt you badly if you manage to mess it up so you don't want to attempt it if you are unsure of what you are doing. You will be working with mains electricity, large power outputs, and heat-generating coils. All of these are potentially quite dangerous. In the end, your setup may not even work -- that rice cooker's heating element is less than 1/4 as powerful as a hot plate's and may not put out enough heat to do the job.

As a first electrical project, I would recommend trying something less dangerous and more likely to work in a satisfactory way. Electric hot plates are not hard to come by for cheap. I would recommend you keep looking for one that will do the job without modification.

I bet I could figure out how to do this job if I had the parts in front of me but I don't think we know enough detail about the wiring of the "probe" and the element to give you good directions, not to mention it's hard to cover all of the relevant safety precautions in a forum like this. Witness the fact that two people who from the sounds of it know quite a bit more about this stuff than I do have just given you quite different instructions on how to proceed (one on the basis that your probe is a thermal relay, the other on the basis that it is a rheostat),

If you do attempt this, use wire nuts to make your connections, secure all your wires so that they can't move around and/or be damaged, make sure you have everything wired up correctly before you turn it on, and have a fire extinguisher handy. Also, plan everyhing out in detail before you start, and give yourself plenty of time to do the job, more than you think you will need.
posted by Scientist at 6:46 PM on June 27, 2012

You are weighing "nonzero odds of hurting myself badly or causing a fire" vs "I can cook with it sooner." It seems obvious how the scale tilts here.

If you can buy the separate parts and do the job safely, won't you still get your technical achievement badge, plus a safer and more reliable rig?
posted by LobsterMitten at 7:01 PM on June 27, 2012

I once tried to make a smoker with an electric griddle. I found that it simply didn't get hot enough to produce enough smoke (it takes quite a bit of heat to make hardwood smoke). I doubt your little rice cooker element will produce enough heat to make much smoke at all with the pan setup that Alton uses.
posted by ssg at 8:44 PM on June 27, 2012

Advice with this (and lots of other things like this). Do it outside, away from anything that will burn too enthusiastically. Do it with a long enough extension cord so that if it suddenly goes up in a pillar of strangely colored smoke, you can unplug it from a safe distance and then sit there and watch, rather than throw water all over an electrically live device or a hot terra cotta pot which is likely to shatter.

That said, the rheostat in the griddle could probably handle the rice cooker heat element, but the rice cooker heat element is unlikely to get as hot as you need it.

You could just as easily manage this sort of thing with a lot less effort and uncertainty by getting some wood chips of the kind you want (Hickory, cherry, mesquite and apple are all good. Oak and walnut are bad!) Soak them in water. Put them in a flow pot drip dray with 2 or 3 lit charcoal briquettes and set up something similar to what Alton Brown was describing. (I've seen more or less this same sort of thing done using the worlds smallest webber kettle style grill as the smoker and a bank of three to five briquettes and some wood shavings on the other side to act as the heat/smoke source and it made for some awesome BBQ.
posted by Kid Charlemagne at 4:41 AM on June 28, 2012

Gerrymander and Jury rig. Please.
posted by Gungho at 6:51 AM on June 28, 2012

Thanks for all the tips. With all of them it mind, it looks like I'll be holding out for a non-modded heat source. I'm already hip to the charcoal barbecuing method Kid Charlemagne mentions; just wanted to try the electric method for comparison.
posted by Rykey at 9:20 AM on June 28, 2012

Flood writes "But, I can tell you that the numbers on the probe will probably not accurately correspond to temperture. Those numbers were placed there to correspond to the heat produced by a different heating element. The probe is not a thermometer the can measure temperature. The probe is a switch - essentially a dimmer switch. If you have a dimmer light switch in your house, turn it half way down and the 100w bulb gives of 50w of light. But turn the same dimmer switch down on a 60w bulb, and now the half way point reading is producing 30w of light."

An electric grill with the long probe is actually a thermostatically controlled device very similar to the thermostat in your stove. It still might not be very accurate because it's calibrated to be stuck in the heat sink of the grill but it'll be fairly precise around whatever set point you dial in. Once you figured out where to set it on the dial that setting should always work.

300W probably isn't enough heat though; that's only as much power as a small Halogen work light.
posted by Mitheral at 5:17 PM on June 28, 2012

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