Glow Plug Soldering Iron




About: I always liked making and fixing things. I also like try and build things myself instead of just buying them.

I was changing the glow plugs in an engine and I thought that with a bit of modification I could make a soldering iron out of one of the old glow plugs.

I just needed to add a handle and a battery cable and I would have a soldering iron, without having to buy one.

Step 1: Materials


  • Glow plug
  • wood off cuts(x2)
  • perforated metal strip
  • M4 bolts(x3)
  • M4 nuts(x3)
  • cable
  • small screw
  • electrical tape
  • crimp on ring terminal
  • crimp on female bullet connector


  • pliers
  • screwdriver
  • drill and 4 mm drill bit
  • sand paper/file
  • wire cutters

Step 2: Glow Plug

Cut a length of perforated strip about 4 inch long. Then bend it around the threaded section of the glow plug and secure it with an M4 bolt and nut. This bolt will also provide a point to attach the negative cable to the glow plug.

Step 3: Handle

I used two wood off cuts about 6" long by 1/2" thick to make the handle.

Use the perforated strip as a template to drill two holes through the wooden pieces. Then use the other two bolts and nuts to bolt them together with the perforated strip in the middle. Secure the other ends of the wood together with a small screw.

Use sandpaper or a file to smooth the edges of the handle to make it more comfortable to hold.

Step 4: Cable

Cut a length of cable and strip the ends of the wires. Then crimp a ring terminal onto the end of the black wire and a female bullet connector on the end of the red wire.

Then attach the ring terminal to the bolt holding the glow plug in and push the bullet connector onto the terminal on the end of the glow plug.

Step 5: Tip

Cut a piece of copper pipe about an inch long (I used 1/4" brake pipe) and flatten one end. Then use a file to shape it to a point. Then push it onto the end of the glow plug (you may have to squash it slightly to get it to stay on).

Step 6: Finished

Now connect the other ends of the wires to a car battery and the tip should heat up, ready for soldering.

The problem that I have found with my soldering iron is that it tends to over heat and burn out the glow plug, so I think that I will either add a switch so that I can switch it on and off, or reduce the amount of current going through it.



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    5 Discussions


    2 years ago

    you need to put some kind of resistance between the battery and the plug. Old way of doing it was a light bulb in series so the power goes through the bulb. Look at the cranking amps of the battery - you are putting all that (200-400 amps) through the short circuit that is the glow plug.

    1 reply

    Reply 1 year ago

    Better yet install a Voltage regulator with current adjust.

    Maker Saga

    2 years ago

    I like the way the connectors attach. I was racking my brain trying to figure out how to make a heating element for a homemade steam sterilization/cleaning drawer, and using a glow plug might just work. Thanks for the inspiration.

    Nice work.


    2 years ago

    ? Great Idea. So things make instructable so unique. Hope see more from you.


    2 years ago

    Thanks for sharing :)