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nichrome resistance wire
meshmasher
I came across the engadget article and tried my hand at modding. Due to a wiring mishap i burned out my primary heating coil in my popper. I spent quite a while digging around this forum and i have found many articles on here talking about nichrome wire on but non in regards to popcorn popper replacement wire.

Does anyone know what gauge/ohm/wattage of nichrome would be best to replace this with?

Thanks in advance.
 
seedlings
For my money, I buy a new popper.

However, are you sure the nichrome wire is actually failed? More likely the thermal fuse or thermostat went out, and you can fix that easy by jumpering across either or both of them.

To replace the coil you have to buy the same diameter and gauge that was in your popper. Measure the resistance and divide your power rating (1200W?) by the line voltage (120V?) and your coil should measure close to 10 ohms.

http://infraredhe...rcoil.html

Or, $2.50 for a new popper at a thrift store. ThumbsUp

CHAD
Roaster: CoffeeAir II 2# DIY air roaster
Grinder: Vintage Grindmaster 500
Brewers: Vintage Cory DCU DCL, Aeropress, Press, Osaka Titanium pourover
 
allenb
I just measured a couple of doughnut style popper elements in my parts graveyard. Both looked identical but one measures out at 11.5 ohms (theoretically 10.5 amps and 1250 watts) and the other measured out to 10.5 ohms (11.5 amps and 1380 watts) so it will totally depend on your unit as to gauge and ohms/foot. Some are wound with nichrome 60 and some with nichrome 80 which will have very different ohms/foot.

With all that being said, Chad has a real good point that it might be much easier to grab another popper unless you've got one of those older harder to find units that you can't afford not to repair.

If you must repair (after you confirm it's the element and not the thermal fuse) then you will need to unwind a foot of it's wire or several, and get the ohms/foot and measure wire diameter in thousandths of an inch. You'll then be able to shop on-line and find a similar wire and re-wind one on a mandrel with the same OD as your coils ID.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
meshmasher
Thanks guys! I have a 115v "popcorn pumper" and the coil is totally fried, thats 100% sure. i have tried to test the ohms but the reading is really erratic and never settles down. Been keeping my eye out at thrift stores for another one as i much rather pay $5 for something im likely to destroy then $20 for a walmart/target model and have it be under powered.

I figured if i had to spend $20 for a new popper i might as well spend it on wire that way if i had another mishap i had more on hand, or i could use the rest to build a custom popper.
 
jedovaty
meshmaster - if you have a biglots nearby, try them, I've seen on occasion very low priced popcorn poppers; don't make an extra trip out to one if it's far, though, call first...

Perhaps a bit off topic (sorry if so) -- let's say you had a nichrome element already, how would one reduce how much power it draws by 20-40%? Err.. safely?
 
Dan
meshmaster, My solution would be a combination of what others have said. I would buy replacement nichrome already coiled. That way I'd have more for repairs or new machines in the future. You only need two measurements: diameter of the wire (so you know what gage it is) and the number of coils on the original element. Once you have the new coil, count out the same number (add some length for termination), snip, and stretch to fit your popper. All of this assumes that both coils are the same diameter coil.

For instance, my sample roaster uses 6.5" of 19 gauge coil.

jedovaty, add resistance to reduce amperage. So, use a longer wire. The formulas are:

Amps = Volts / Ohms
Watts = (Volts * Volts) / Ohms

Here are all the formulas. E = volts, I = amperage, and of course R = resistance, and W = watts.

claycritters.com/misc/ohms%20law.gif
 
allenb
My bad!,

I mentioned above that the ohms/ft between nichrome 60 and 80 were very different but it aint so.

The table I just looked at on Pelican wire site shows that NiCr 60 22 gauge is 1.055 ohms/ft and NiCr 80 22 gauge is 1.017 ohms/ft which comes out to around 46 watts difference between the two if you copied the doughnut coils I referred to above using NiCr 60 and NiCr 80.

This wattage difference is the same you would find going from 120 volts to 118 volts so not a big deal.

Allen
1/2 lb and 1 lb drum, Siemens Sirocco fluidbed, presspot, chemex, cajun biggin brewer from the backwoods of Louisiana
 
jedovaty
Dan - nice graph, helpful! Assume nichrome length is fixed. Now what? :)
 
Dan
Technically, that's a diagram. I don't understand your question.
 
jedovaty
Your solution was to get a longer piece of nichrome. Assume I have a fixed length. How do I reduce the power? Is there a way to drop the voltage? Add other resistors (no idea how that would work on AC though)? My piece of nichrome draws about 8 Amps, I need to drop it to 4 or 5.
 
Dan
Most heaters use coiled nichrome wire, which means the length is adjustable depending on how far you stretch out the coils, which is what I assume you had, too.

If your heater uses straight or taught wire, then the solution is still the same, add resistance. In your case you'd use a smaller diameter wire. You'd need to compare resistance per inch between your wire and then look for something that is 8/4ths (double) or 8/5ths more.
 
meshmasher
Awesome, Thanks so much guys! i got a few pounds of green coffee for christmas and have been dying to roast again!
 
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