Nichrome 80 vs Kanthal A-1 Heat Flux

[Justadude]

I heard that Nichrome heats up way faster than Kanthal, if that's true then why is the heat flux lower?

Nichrome
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Kanthal
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[Rat2chat2]

Great question. It is my understanding that you can use more wraps with Nichrome and with more surface it is suppose to be better vapor but not really sure. I am looking forward to the answers so I can learn something also.

 

[Justadude]

Yup. I've heard countless of times that nichrome heats up faster. But that doesn't line up with heat flux numbers when you compare the two. Hopefully the wire gurus see this thread and shine some knowledge on this topic.

 

[Rossum]

I believe the reputation of "heats up faster" comes from the fact coil with the same geometry (wire gauge, diameter, number of wraps) made from nichrome will have a lower resistance (and thus pull more power from a voltage source) than if it were made from kanthal.

Now if you make two coils with the same resistance, they will pull the same power, but the nichrome coil will need to be bigger (either in diameter or number of wraps) and of course the heat flux will be lower.

 

[Justadude]

I believe the reputation of "heats up faster" comes from the fact coil with the same geometry (wire gauge, diameter, number of wraps) made from nichrome will have a lower resistance (and thus pull more power from a voltage source) than if it were made from kanthal.

Now if you make two coils with the same resistance, they will pull the same power, but the nichrome coil will need to be bigger (either in diameter or number of wraps) and of course the heat flux will be lower.

So is it because of what Nichrome is naturally made out of (Nickel and Chromium) that makes it to be a lower resistance wire?

Also - to re-literate - because Nichrome is lower in resistance - we would need more wire, thus more resistance, in order to match Kanthal wire in order to achieve the same resistance number. Is that correct?

 

[Sgt.Rock]

So is it because of what Nichrome is naturally made out of (Nickel and Chromium) that makes it to be a lower resistance wire?

Also - to re-literate - because Nichrome is lower in resistance - we would need more wire, thus more resistance, in order to match Kanthal wire in order to achieve the same resistance number. Is that correct?

Yes and Yes

You need almost twice as long a piece of NiChrome if both are the same diameter.

 

[readeuler]

So is it because of what Nichrome is naturally made out of (Nickel and Chromium) that makes it to be a lower resistance wire?

Also - to re-literate - because Nichrome is lower in resistance - we would need more wire, thus more resistance, in order to match Kanthal wire in order to achieve the same resistance number. Is that correct?

More or less. Keep in mind what heat flux is: it's simply a "per unit surface area" measure of the amount of power given to the coil. So you take the wattage, and divide by the surface area of the coil, it tells you how concentrated or dispersed the heat is.

So, since Nichrome has a lower resistance per unit length, you'll need more Nichrome (assuming a fixed wire gauge) to achieve a given resistance. At this given resistance, we've got a fixed wattage but more wire hence more surface area. This means lower heat flux (we're dividing the same power by a larger number); physically the same heat has to be more spread out.

 

[Justadude]

Ok so I've built a clapton coil 2 days ago. 3 wraps, 28g kanthal around 24g kanthal. Takes about 5 seconds to get hot sitting at .35 ohms of res with 3 mm in diameter. People have said that using nichrome would heat it up faster. Assuming all the parameters would be the same for nichrome that would heat up nichrome even faster and give me a lower resistance?

 

[Justadude]

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