Just got one for use with a fret burner. Since it is a power supply usable several ways, is it a viable idea to put a dimmer switch between the Variac and whatever is being powered? That way you could set the voltage on the Variac, but do the controlling with the dimmer,  the dimmer maxing out at the set voltage. With proper operation, you'd never blow anything up, the power can never go overlooad.

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  • I've used a hot wire for years to cut foam for model airplanes. The first thing you notice is his use of a 12V battery charger.   This doesn't eliminate the burn risk, but brings the voltage to a safe level.

    Modern battery chargers are electronic, and won't work... you need an older one that doesn't auto-cutoff or look for a battery. (Basically, see if it produces 14ish volts with nothing connected on the battery end.)

    THEN you can use your variac to reduce the voltage to what you need...

    And no, a household dimmer is not necessary...

    • The whole idea of the dimmer was to act as a safety. If the Variac was set to 9-12 volts, doesn't matter what you do with the dimmer (or light switch for that matter) voltage will never go over 9-12 volts.

      So is it the AC that everyone is worrying about? I can sell the variac on ebay...

    • OK, what about 6 volt lantern batteries, with an on/off switch?

  • Not to ruffle any feather here but what I saw in at video was someone doing something incredibly dangerous and stupid. It's one of those things that just because it can be done doesn't mean it should. There are far better, safer and cheaper was to get the same thing done. 

    • Please explain...

      • First. There is no protection between him and that wire. No protection if that wire should explode. I've seen what happens when a small piece of heated material enters the body. It causes a very wide and deep burn. That's a sorry way to lose a hand. Even if he accidentally touches that wire he could lose the use of a finger. 

        Second. He has open current within reach. Ever hear of a taser? They are DC current too. People can die from a taser strike. What he has in front of him has way more current flowing through it. He is risking his life.

        • Is there a safe way in your opinion to create such a device?

          • Completely incase both the electrical hazard and the heat hazard so there's no way to come in contact. This would also insure no moisture would touch the heating element. You would have to come up with a way to line the fretboard up without ever directly looking at the element. Possibly a templet and peg system for each scale length needed. 

            • Isn't nichrome wire made to be filament? Labeling says it's good to 2550F...not that I'd ever be up there...

              • Touching the business end of a soldering iron will burn you. Touching anything red hot will damage you. Having something like that out in the open is asking for trouble. 

                Do what you want, Just saying that setup is insanely dangerous.  

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