nichrome wire gauge?

Hello all.

What is the recomended gauge value for the nichrome wire?

Thank you

Power resistors are more robust and easier to use than nichrome. If you insist on using it, then the reprap standard is 6.5Ohm per 30cm. I believe this works out to around 32SWG, but the important factor is the how long you will need to get the resistance you want.

I've used 30ga and 31ga nichrome very successfully. The 30ga works out as mentioned above to about 6.5ohms per foot, the 31ga is about 8.2 PLMs per foot, so you want it about 50cm shorter for the same settings in your firmware. I don't agree with the comment about power resistors being more robust; they are usually in a brass or aluminum block which gives you more thermal mass and thus take longer to get up to operating temperature and fluctuate less while at temperature, but accurate PID settings on a nichrome-wrapped hotend can negate that advantage.

Mkouri Wrote:
-------------------------------------------------------
> I don't agree with the comment about power resistors
> being more robust; they are usually in a brass or
> aluminum block which gives you more thermal mass
> and thus take longer to get up to operating
> temperature and fluctuate less while at
> temperature, but accurate PID settings on a
> nichrome-wrapped hotend can negate that advantage.

The normal power resistors used in hot-ends are enamel coated, and have very little thermal mass. They are basically a nichrome wound cylinder. They are easier to use and less likely to short, as the insulation on nichrome wire tends to come off after a while.

Edit: I have used both types of hot-ends extensively.

Edited 1 time(s). Last edit at 06/02/2012 01:36AM by NewPerfection.

I've got and use both types as well. I was referring to the brass or aluminum block giving more thermal mass. Ceramic blobs like Makergear uses or fire cement or muffler cement like many other people have used can address the insulation issues with nichrome wire, but yeah I guess you're right - power resistor hotends can take more rough handling than nichrome wire hot ends.

My mistake, I thought you were referring to aluminum-housed power resistors, which MakerBot used on their MK6 hot ends. I love my MakerGear hot end, but the cement does start to chip and flake off after a while. It's finicky to wrap the nichrome and cement it too. But you do end up with a more compact hot end with less heat loss.