Recycling an Old Soldering Iron Into a Heated Knife




Introduction: Recycling an Old Soldering Iron Into a Heated Knife

About: I am a die hard Anaheim Ducks hockey fan. I love to take things apart and design/build innovative things and I am always thinking of something to build. In my spare time I love surfing, even though the word ...

Have you ever needed a tool, that you don't have? This happened to me, but instead of stumping me, it inspired me into making my own version of this tool. I had an old soldering iron that was no longer capable of melting solder, so I put two and two together and got this. I made a heated knife for cutting through styrofoam. Everybody uses this tool differently for different projects and my purpose for it may or may not appear on instructables. Regardless, this is a great tool to have and has some great modifications that I decided to add to it, such as the wooden shaft and the silicone gel handle grip. So lets hop into this awesome project!

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Step 1: Materials

All that you are going to need is this:


soldering iron



corn starch





maybe a couple other misc. tools to help you

Step 2: Disassembling the Soldering Iron

Start by disassembling your soldering iron, it has a removable tip then you can just remove that (unless you want to make the handle) and your good. You need to get rid of the tip for future replacement with the nail.

Step 3: Building the Blade

For, the blade, just take a nail (with a small enough shaft to fit in the removable tip of the heater, if you have a removable tip) cut off the head of the nail (I used a hacksaw) and hammer the tip to get it flat. Once it is flat enough then you can take a file and start sharpening one side (I also filed down the tip so it wouldn't be as sharp, you don't usually need a sharp tip anyway). Once the desired tip is formed then you can move on.

Step 4: Reassembling the Knife

Now you just reassemble you new knife. But remember to leave the handle off if you want to make a custom one.

Step 5: Making the Handle

First I found a wooden broom handle and cut off a little bit. Then I found a drill bit that was about the same size as the knife. Then just drill a hole in the middle of the wood handle and slide your knife in. (mine had a convenient split that i could slide the wires right through but you might not be as lucky, so you can cut and re-solder the wire)

Step 6: Patching Up

It is now time to patch up any flaws in our handle. As I stated in the last step, mine had a convenient split, so I used silicone to glue it back together and keep it solid.

Step 7: Making Your Silicone for the Handle

Now you need to get some silicone, a container, and your cornstarch. Put the silicone in the container and then also put in some cornstarch. Then mix it up. If you need a thicker consistency then just add more cornstarch. Basically I made a sugru substitute, it was made by Mikey77 (who calls the substitute Oogroo) in this instructable here. It would be smart to check out his explanation because he explains it a lot better than me.

Step 8: ?Dyeing the Oogroo?

In theory, you can dye Oogroo with a little bit of food coloring, be warned though, it takes a lot of work to mix it all in, I gave up after a little while so mine was only partially dyed. You guys tell me if it does work if you figure it out.

Step 9: Forming the Handle

Using the Oogroo,we are going to form your custom handle for your knife. It is really nice to have a bowl of water close by to put your hands in so the silicone doesn't stick to your wet hands and makes the whole process easier. Just pile on the Oogroo and shape it to the desired shape and then set it out to cure. I used a vice to hold the handle so it wouldn't touch anything and hinder the shape of the handle. Now you have your silicone gel handle done.

Your heated knife is done. I hope you enjoy and don't forget to vote!

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