Heating Elements for Soldering Iron
James Newman
Posts: 133
I'd like to play around with making my own soldering iron.
I've taken apart the cheap ones and see that they're just resistance wire strait to the 110 ac, sometimes with a switch and diode to provide 2 different power ratings. I was thinking about wrapping my own regular low resistance wire about 1 ohms worth or so and and using a 5 volt supply for a 25 watt iron. Finally if that works, I was thinking about using a mosfet and a pwm circuit to make it variable.
So, 2 questions. First is what am I overlooking that will make this not work. Second is what can I use for insulation around my wire? Theres a flaky paperish type on most of the cheap irons, but I don't have any of that. I just need something to insulate the coil from the rest of the iron, and withstand up to 800 F or so. (Incase I up it to a higher wattage later and need to do some desoldering.
I know I should buy a good iron, especially for the tips, but I kinda want to do this as I've been playing around with current control lately anyway.
Thanks.
PS: Not so much robotics... wasn't sure were it belonged.
I've taken apart the cheap ones and see that they're just resistance wire strait to the 110 ac, sometimes with a switch and diode to provide 2 different power ratings. I was thinking about wrapping my own regular low resistance wire about 1 ohms worth or so and and using a 5 volt supply for a 25 watt iron. Finally if that works, I was thinking about using a mosfet and a pwm circuit to make it variable.
So, 2 questions. First is what am I overlooking that will make this not work. Second is what can I use for insulation around my wire? Theres a flaky paperish type on most of the cheap irons, but I don't have any of that. I just need something to insulate the coil from the rest of the iron, and withstand up to 800 F or so. (Incase I up it to a higher wattage later and need to do some desoldering.
I know I should buy a good iron, especially for the tips, but I kinda want to do this as I've been playing around with current control lately anyway.
Thanks.
PS: Not so much robotics... wasn't sure were it belonged.
Comments
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PG
I have some Nichrome, but it's such high resistance, and I don't have any high voltage around... I guess I could use the 110 and rectify it first so I can use it with the mosfets...?
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Chris Savage
Parallax Engineering
The Test Forum: "Use this forum to test signatures, posts, etc."
From the title page...
Any soldering iron worth using has temperature control.· Nothing you've suggested would give you temperature control.· You need a temperature-sensing element of some kind, and a control loop.
Some of the best commercial ones use tips that are magnetic at low temperatures, and become nonmagnetic at some higher temperature, say 800 degrees.· Every ferromagnetic material has a temperature (called the Curie point) above which it becomes nonmagnetic.· You can buy tips with various Curie temperatures.
The body of such an iron contains a switch with a magnet on it.· When there's no tip installed, or when the installed tip is hot enough not to attract the magnet, the iron is switched off.· When the installed tip is magnetic, and attracts the magnet, the switch is closed and the iron heats up.
You could use a thermocouple instead, or some other kind of temperature sensor -- but if you don't put some kind of sensor there and control the temperature, your iron won't be very good.
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· -- Carl, nn5i@arrl.net