Introduction: Hot Knife for Plastic Cutting!

Picture of Hot Knife for Plastic Cutting!

Probably, the EASIEST Instructable you'll ever see to make the most useful tool a DIYer could ever wish for! Sometimes "simple" is the answer....

Step 1: Get a New Soldering Tip!

Picture of Get a New Soldering Tip!

Then take a hammer to the end of it until it's nice and flat.

Step 2: Screw It!

Picture of Screw It!

Back on your soldering iron!

Step 3: Cut Stuff!

Picture of Cut Stuff!

Works amazingly well on any kind and thickness of plastic. Makes custom modding and DIYs a breeze. The best part is, you can switch back to your soldering tip when you're done cutting! 8D

Wasn't that easy? If you want to, feel free to check out the video that shows how much crap I went through to get to this! Watching this helps me keep coming up with these ideas... a blatant attempt to promote a video I admit ;)

But it's a pretty amusing example of how hard it can be to come up with a simple solution...


OwenD1 (author)2015-01-04

You could also just heat an old paring knife with a torch.

huttarl (author)OwenD12017-01-16

Have you tried that? I tried with a utility knife, and it didn't cut very far. I think the blade cools down too quickly, which is why you need a soldering iron.

exabopper (author)2010-12-05

This is just about the greatest thing in Instructables, but I had trouble making it - hitting the tip with a hammer just caused it to shatter, not flatten. I would use a grinder to harrow the tip down instead of hammering, especially with a cheap iron.

shannonlove (author)exabopper2013-01-19

If a tip has seen some use, it will be progressively contaminated on the surface with solder and other material. This will cause the outside to become harder or softer than the inside. During the thermal stress of heating up and cooling down, the tip fills with micro fissures. More material migrates down the micro fissures until the tip is just a giant brittle puzzle box waiting to happen.

And that's about all the metallurgy I remember from college.

Nickson Yap (author)exabopper2012-12-18

Well, you could try to hammer the tip with it installed and heated by the soldering iron.
It should be pretty soft...

guitar-is-awesome (author)2010-09-05

is this safe? i need to cut thru a sheet of plastic thats pretty thick and think this might be a solution!

You should wear a respirator, safety googles, do it outside, and keep a bucket of water near by should the plastic catch fire. The reason for this, is the plastic my let of fumes or smoke that will be toxic.

This is ideal for places that a Dermel can't reach or can't cut precisely otherwise you should be using a Dremel.

anthonyyy0 (author)2010-09-01

would this be an appropriote tool to cut a design on the side of my wii? (after i remove the case of course)

mman1506 (author)anthonyyy02010-12-05

use a dremel instead it will be much cleaner

AZombieHippie (author)2010-06-15

hey thanks for the idea i'll include your idea and give you credit in my next instructable! :)

woodvale035 (author)2009-08-14

good idea i have done this on an old soldering iron so i could cut and seal nylon type rope all in one go. it was a pain when cutting rope for use on the boat so i made a blade like yours, now i have plastic cutter in my tool box without doing anything...he he .
it does stink a bit tho..

thoraxe (author)2008-01-18

Nice Hammer. I am doing blacksmithing, and a hammer like that would be nice. I am currently using your standard run-of-the-mill claw hammer, which is too round and gives me an uneven bevel when I forge blades. I've been thinking of making my own hammer, but i never got around too it.

trf (author)thoraxe2009-02-26

bro if ur gonna forge metals do yourself a favor and go buy a 3 lb sledge i paid $10 you can get them for $10-$20 and its really worth it. Large flat head (yes less dents and rounded areas) and also the weight flattens metal alot quicker!

BigNateMI (author)thoraxe2008-02-18

When I started blacksmithing, I just used a cheap cross peen hammer like the one shown here. I removed the machined finish from the face with an angle grinder and a flap sanding wheel. I also blunted the peen somewhat with the grinder, then polished it with the flap sander. It cost about $3, but I already had the grinder.

!Andrew_Modder! (author)2007-10-06

:-\ when i cut plastic, i just blow torch a crappy pocket knifes blade, then cut the stuff. or take a razor blade and make the tip red hot, then cut.

pyro13 (author)!Andrew_Modder!2008-08-06

Same here,

Mr. Rig It (author)2007-10-06

This is a good idea. You are right sometimes simple is the answer.
Check out my circle ible The circle

Hopefully it will give you even more ideas.
I will keep this one in mind.

babblin5 (author)Mr. Rig It2007-10-06

I checked that out... Very Cool idea Mr. Rig It!=D

Spectrace (author)2007-10-06

did you try using a chisel tip ? would have been easier to hammer that down than a point tip. and if you can find a thin one, no hammering needed.

babblin5 (author)Spectrace2007-10-06

I like that I'm able to fashion an Xacto knife-like tip from the natural tapered soldering tip. A little filing and you have a great point that lets you cut curves, shapes, etc. You CAN buy special tips that will do the same thing, but they tend to be brittle and cost more...

Handsome-Ryan (author)2007-10-06


babblin5 (author)Handsome-Ryan2007-10-06

Thanks! And it only cost me about $30 to figure this out...rofl 8D

About This Instructable



Bio: I've had many different jobs in my life, but I've discovered my passion: Mental Health Counseling. However, that doesn't keep me from ... More »
More by babblin5:View the Solar Eclipse Using... a Tree?Paper, Plastic, or Furoshiki?Fire from a Dead Lighter
Add instructable to: