Make a Hot Knife using a soldering iron

Are you having trouble cutting plastics with an ordinary x-acto knife? Then here is a simple tool mod you can do, turn an old soldering iron and a x-acto blade into a Hot Knife!

This hot knife idea isn't really mine, I found this idea made by somebody from MAKE:, I can't remember who made it. And so I decide to make one for my self to make my life of cutting hard plastic easier.

^{Disclaimer: This is a fairly dangerous work tool, it can burn and/or cut you if you misuse it. And I am not responsible what ever happens to you with this tool mod.}

Step 1: What you will need...

You will need:

• Any soldering iron will do - the higher the wattage, the better
• A nasty old soldering iron bit you don't want to use.
• A spare x-acto blade

Because I don't have a welder which is most recommended for this mod, I will have to use a different technique to attach the blade to the soldering iron bit...

My idea is to cut a groove into the soldering iron bit with my dremel with a cutting head. Then put the blade into the groove and squeeze the soldering iron bit onto the blade using the vice.

Comments

[huck alexander]

This is a great idea! Have been looking for a more efficient way of trimming plastic parts. This idea will adapt nicely to my requirements. Thanks!

[mrmerino]

At least if you cut yourself with it, it'll cauterize itself.

[ilpug]

Yeah, a built-in "Safety device."

[aireal]

The flat blade might be causing to much heat loss (due to a larger surface area).

I am also worried about how much downward pressure you can put on this when cutting.

But great idea. Thanks for the insperation.

[killbox]

pressure is reall ynot needed, just go slow and let the melt do the work.

[awang8]

I'll give this a try when my current soldering iron tip is rusty enough to be qualified as a "A nasty old soldering iron bit you don't want to use.".

[Plasmana]

LOL! I am not trying to say use a soldering bit that you don't use that much anymore because you are going to destroy it. You can use a new one or an old one.

[awang8]

Yeah, I realised but for two things... *I'm the kind of guy that hates destroying things that you can still use, even if it is destroying it to make something awesome *The local electronics shop only sells Weller tips ($29.99!) and I hate buying online I'm not going to use a new one. PS: If you're wondering how I'm supposed to get a new tip when my current one is a knife then yes I will buy a new new iron ($10).

[killbox]

I just posted an instructable about this. about the one ive been using, for one out of the two irons i used i didnt have to modify the iron at all. I found the cheapo exacto knifes you can buy at places like ace hardware (with a plastic handle) fit where the tip was in an old iron. let me replace blades. and also if i need to solder with it pop out the tip and put in the non knife one. (the other iron i did have to tap out a little bit to get it to fit. works best on irons where there is jsut a screw on the side to hold the tip in.

[comander01]

If the new Iron is $10, why would anyone buy a $30 tip?

[ARJOON]

THat u pretty expensive for a tip. in maurititius a tip cost me Rs5 or $0.2 yeah the big one

[Plasmana]

Good point...

[xproplayer]

i could just see someone a huge pile of old irons in ur workshop plasmana

[xproplayer]

wow i just realized that is the worst grammar ever!!
i mean to say i can just someone like plasmana having a huge pile of soldering irons laying around in ther work shop if you hook em all up a once u have a heater!

[techno guy]

I was thinking that you could attach the blade by soldering it but that would fall apart as soon as you turn it on.

[MrHanimi]

Ah yes! :)
now i can cut through plastic like a hot knife through....
through...

I'll get back to you on this one.
nice instructable :)

[DELETED_gabethegeek]

(removed by author or community request)

[Plasmana]

Lead dust? From where?

[DELETED_gabethegeek]

(removed by author or community request)

[Plasmana]

Oh dear... The lead was once on the bit from soldering and now it is in my lungs!! AHHHH!!

[sk8erdude]

Actually there isn't lead in the air that is the flux boiling off. lead melts at very high temperatures let alone evaporate so there isn't actually anything to worry about! Keep up the good work, -SK8ERDUDE

[Lhtrf]

actually, theres lead in solder to make it melt at LOWER temperature, but still, nowhere near enough heat to make it evaporate.

[Blofish]

I like the warning cut yourself and cauterize at the same time LOL

[wolfs2424]

Good idea,  has many uses like removing insulation from thin wires and saves money

[punkhead58]

A little 'bit of epoxy couldn't hurt either.

[Plasmana]

Wouldn't it burn off?

[karnold70]

If you have the equipment and the patience, I'd recomend using a tap to thread one half of the 'hole'. use the next size larger drill bit on the other half so it will squeeze.

[tiekietemboe]

What is a x-acto blade and where do you get it?

[Aggrieved]

x-acto blades are just a name for the general craft knife blade. any art supply store will have them and they will all fit into a standard handle.

[xproplayer]

i have to funny stories for this first when i tried to take out my old soldering iron bit it broke leaving the threads still in then when i was clamping the blade it took like the hulk to get it even after practically braking the vice it still is not rock solid

[Mr. Thrak]

you could *ahem* solder it to the iron.

[Mr. Thrak]

I think a candle would do better. o.O

[cleversomeday]

An additional tip. If you secure your hot knife between the planks of a Workmate work bench you have an instant table saw type of arrangement. Photos of side view and in action attached.

[=SMART=]

Thats Awesome

[lordofthedonuts]

I've tried to make something like that with and old solerding iron, but this one is way easier. I can't wait to injure myself horribly with that!

[awang8]

Quote from lordofthedonuts: I can't wait to injure myself horribly with that! Isn't that kinda emo?

[Foxtrot70]

Hi Awang8 - Please forgive me, I am not well versed in internet shorthand so, what does EMO stand for?

[struckbyanarrow]

EMOtional

[xproplayer]

emo is not shorthand but is a term for people who like to be goth dress all black talk about death and most commonly cut themselves purposly

[busterdavidson]

Emo is shorthand.