Crimp vs stainless steel intermediary for copper and nichrome connections in a heating element. Any difference in speed of heating?

Question

I'm designing an electric furnace to melt aluminium. I'm planning to use the heating element from an electric oven.

I'm aware that the melting temp for aluminium is lower than copper BUT I don't want to fly too close to the sun. So as ​an added precaution to stop the copper wires from overheating I'm planning to use stainless steel intermediaries between the copper and nichrome connections (instead of using a good crimp to insulate the copper).

Could using these intermediaries slow down the speed at which the element heats up (in comparison to other methods?) If yes, would it be possible to calculate the extent to which the heating process would be slowed down?

Thanks

Answer 1

As far as impacting the heating of the Nichrome portion of the wire run, it won't even matter if the length of NiChrome is significantly higher resistance than the length of stainless steel wire. In that case, the power/heat dissipation lost in the low resistance portion will be negligible compared to the high resistance portion.

That said, the resistance of 304 stainless steel is 80% the resistance of Nichrome so you aren't doing much by having a stainless run in there if it is the same gauge as the Nichrome. In that case, the stainless is going to be a heating element in and of itself comparable to the Nichrome and will generate 80% the heat of the Nichrome wire per length.

What I would do instead is run a larger gauge (significantly larger if possible so you can get at least 10x less per length resistance) of stainless steel. Then not only does the stainless steel will run cooler and also rob less power that would otherwise be going to heat the Nichrome. I mean...you could make the same extension with a larger gauge of Nichrome but that's a waste of money.