Fog machine coil failure took me 4 weekends to diagnose

I spent a whole month trying to figure out why my homebuilt fog machine kept sputtering and dying after 5 minutes. Turned out the heating coil wire I got from a random Amazon seller was too thin for the 120V setup I was running. By the time I swapped it with a proper 14-gauge nichrome wire from McMaster-Carr, I had already rebuilt the pump and fluid reservoir twice. Has anyone else wasted tons of time on a connector or wire that just wasnt rated for the heat?

3 comments

3 Comments

dylanward1mo ago

I used to be one of those guys who thought wire was wire, like as long as it looked thick enough it would work. Then I built a small induction heater and ran 18-gauge speaker wire for the coil because it was what I had lying around. It melted through the insulation in about three minutes and almost started a fire on my workbench. That was the moment I stopped guessing and actually started looking at ampacity charts for everything. Now I check the temperature rating and current capacity on any wire before I even plug it in, and it saves me from chasing ghosts in the system. Have you had any other projects where the wire totally wrecked your timeline?

ray_king9d agoMost Upvoted

That 18-gauge speaker wire story is terrifying man, I've seen similar stuff with people using doorbell wire for 120v lamps and wondering why the insulation melts. @skyler_kim is dead right about the Amazon spools too, it's wild how often cheap wire is undersized or has way lower temp rating than it claims, that same principle applies to extension cords and even phone chargers now.

skyler_kim1mo ago

Man, that "too thin wire" thing hit home for me. I had a similar issue with a small DIY kiln where the heating element kept burning out after like 20 minutes. I spent two weekends checking the controller and temperature sensor before I realized the wire gauge was way off for the current I was pulling. In my experience, those cheap spools on Amazon are never what they say they are. I switched to a thicker gauge like you did from a proper supply place, and it solved everything. Good call on the 14-gauge nichrome, that stuff handles the heat way better. Your mileage may vary, but checking the wire rating before anything else is now step one for me on any high-heat build.

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