What resistance for a heating coil?

[Dirtman]

Oddball question... I'm making a new smoke machine, basically just wrapping resistor wire around a bundle of tiki torch wicks that will be soaked in mineral oil. I've seen this done before and seen it work well.

Here's the question, how many ohms of resistance should i shoot for in order for the wire to get hot enough to smoke the oil but not disintegrate with a 12 volt power source (car battery)

The best answer I've found searching the internet is 2ohms which is aprox 2.5 feet of 20 gauge resistor wire. Does this sound right? I have plenty of wire to experiment with, just trying to get a good rough guess to start with.

 

[Snoranger]

I’ve never built one, but a quick search says that 2 ohm is about what you want. Or, you can just borrow my Blue Point smoke machine.

 

[Dirtman]

Thanks for the offer. Im building it more for something to do rather than really needing one at the moment.

My old one is literally just a paint can with burning rags in it.

 

[sheep herder]

 

[Dirtman]

2.1 ohms was perfect, came out to about 30 inches of 20 guage kanthal wire wrapped around the wick.

I just mocked it up to see if it would work, took about 20-30 seconds to warm up fully and it started pouring out smoke like a broken chevy and that was with no airflow. Didn't get a pic of the smoke but I assure you it was there. Now just gotta put it all together.

 

[alwaysFlOoReD]

So what is it for? Mosquito repellent? Disco dancing? You want the neighbors to worry?

 

[Dirtman]

So what is it for? Mosquito repellent? Disco dancing? You want the neighbors to worry?

Never used an engine smoke machine? You pump smoke into an engine to find vacuum leaks. Air isn't visible, smoke is. Or are you joking?

 

[alwaysFlOoReD]

@Dirtman
It never occurred to me. So yes, I was joking.
I've never used an engine smoke machine. I've read about it here on TRS, but have no idea how it works. Willing to give a short rundown on how one works?

 

[Dirtman]

Simple, you literally just pump smoke at a very low pressure into the engine through a vacuum line or at the throttle body and then watch to see where the smoke comes out. Even tiny vacuum leaks become very visible when smoke starts coming out.

You can do the same for the evap system by pumping the smoke into the filler neck or the vent line.

The machine im making is the heating coil on a wick soaked in mineral oil. The coil heats up and starts smoking the oil. When its assembled there is an air inlet from my air compressor attached to a propane grill regulator (2psi) and then an outlet hose which simply gets plugged into the engine somehow (usually a vacuum line). Pretty simple device but for some reason they cost hudreds, sometimes thousands of dollars which is why i refuse to buy one.

Next to my scanner i think smoke is my second favorite automotive tool...