Styrofoam weapons

bevbor

Well-Known Member
Hi all,
today I made styrofoam cutter.
From scrap of trash really.

2088748124_b8e451e34d_b.jpg

2087961251_bcaed3a605_b.jpg


Length of hot cutting wire about 26 cm.
Powered by broken computer power supply - 12 volt.

Budget:
plate (perfect wood covered by aluminium sheet, I even dont know
what it was intended for) - got it on scrap heap - 0 bux;
upper aluminium holder - from scrap heap - 0 bux;
hotwire - disassembled from old broken iron - 0 bux;
10 screws - it was somewhere around already - 0 bux;
powersupply - from old p3 computer - 0 bux;
wires and connectors - from the same place - 0 bux;
2 paperclips for holding hotwire - 0 bux;
4 "legs" - just was in my instrument box for years - 0 bux;
Overall - 0 bux. :)

Lets see tomorrow what I can do with all of this...

Best regards
 
Very nice build out of scrap! Cant wait to see how it works out. if it works good you should consider making a Tut on how to build one for the site.
 

Epyon

Jr Member
that's awesome! Hotwire cutters = dabomb for styrofoam.

ONE WORD OF ADVICE!
put a potentiometer knob or something on there so that you can slowly increase and change the voltage going through the wire.....that way you can have the right amount going through it no matter what length you use....otherwise you might overload it and it'll snap on you.

Be careful!

other than that, hotwires are awesome :D

Good luck!

~Epyon
 

bevbor

Well-Known Member
First of all, I did print of pistol (thanks to Vrogy) - to cut it off of paper and then to pin it to styrofoam board.

2089490648_13f9376c35_b.jpg
 

bevbor

Well-Known Member
Epyon said:
ONE WORD OF ADVICE!
put a potentiometer knob or something on there so that you can slowly increase and change the voltage going through the wire.....that way you can have the right amount going through it no matter what length you use....otherwise you might overload it and it'll snap on you.

Be careful!
Thank you very much for advice, but I'm not so familiar with electrical calculations, what potentiometer exactly I need to use in such circuit?
Also I've got advice of other kind from people working with chemicals - to add air duct to suck out the steam and smoke of melted styrofoam because they are extremely cancerogenic =(
 
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Epyon

Jr Member
bevbor said:
Thank you very much for advice, but I'm not so familiar with electrical calculations, what potentiometer exactly I need to use in such circuit?
Also I've got advice of other kind from people working with chemicals - to add air duct to suck out the steam and smoke of melted styrofoam because they are extremely cancerogenic =(

Oh, yeah! I didn't know you were thinking of using it in an unventilated area.....hehe :D YES, you will want to ventilate those fumes....

As for potentiometer, It'd probably need to be more than just the 1-10k Ohm ones that you find in radioshack.....it'd also tend to make this wire cutter more of a permanent tool, BUT you'll have added safety and variability (like changing the length of the wire and still using the same circuit setup).

Potentiometer is just a big word for "big knob that increases resistance as you turn it up", its just a giant resistor that you can change its resistance....its how volume knobs work :D

For a 12volt system like that, and a short-ish wire.....(like, not 2-4 ft long), you could get away with a few small ones in series....

I'd say go get 2-3 of the small ones from radio shack and try those in series......you can just turn one up until it gets to where you want (wire just barely before turning red), if 1 is not enough, then turn the 2nd one up some, and so forth.....

You'd kinda have to play with it a bit. If you have any more questions, or want me to wrap up some more details for ya, just shoot em my way...I'm happy to help.

~Epyon


EDIT:

Yeah, re-looking at your picture of it up top, I think you'll be fine....just watch for the color of the wire, that's all it really is. If it's getting red, then you'll want some resistance out of a potentiometer. If it's not, then you should be okay.
 
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bevbor

Well-Known Member
Nothing goes right.
Wire is overvoltaged.
Potentiometer added to circuit got exploded after 5 seconds of its work.
Here the sad result.
2090890209_7a1086c392_b.jpg

Best regards.
 

bevbor

Well-Known Member
Spartan-K22 said:
trash container? whats that?
My English is bad, sorry! I mean garbage collector, scrap heap etc.
These parts I used - I took them from some computer monitor packing box.
 
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K-22 and bevbor you could get styrofoam from the dump. i mean it would be free. or you could go to tracto suply co. around here they always have huge styro blocks out front that say free.
 

bevbor

Well-Known Member
Durlaburban said:
K-22 and bevbor you could get styrofoam from the dump. i mean it would be free. or you could go to tracto suply co. around here they always have huge styro blocks out front that say free.
K-22 is lazy and waiting you make him helmet. :)
Do you belive he can go get styrofoam block? :)

2 K-22: nothing personal, dude!
 
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bevbor said:
K-22 is lazy and waiting you make him helmet. :)
Do you belive he can go get styrofoam block? :)

2 K-22: nothing personal, dude!
Bevbor your my hero!! hes nagging me so much the rest if you caught on!! lol
 
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bevbor

Well-Known Member
Epyon said:
You'd kinda have to play with it a bit. If you have any more questions, or want me to wrap up some more details for ya, just shoot em my way...I'm happy to help.

~Epyon
EDIT:

Yeah, re-looking at your picture of it up top, I think you'll be fine....just watch for the color of the wire, that's all it really is. If it's getting red, then you'll want some resistance out of a potentiometer. If it's not, then you should be okay.
Thank you for help.
My wire is never getting red, but is too short for 12 volts. It heats foam too much, so foam melts in radius of 1 mm around wire. That is absolutely not supposed to be. So I added potentiometer as you said - only I had was 40 kOhm, and it got exploded in seconds. After this, knowing people told me that it's power must be no less than 0.5 Amper =(
Now I seek for such a thing.
 
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Epyon

Jr Member
bevbor said:
Thank you for help.
My wire is never getting red, but is too short for 12 volts. It heats foam too much, so foam melts in radius of 1 mm around wire. That is absolutely not supposed to be. So I added potentiometer as you said - only I had was 40 kOhm, and it got exploded in seconds. After this, knowing people told me that it's power must be no less than 0.5 Amper =(
Now I seek for such a thing.

Ah hah! Easier fix then I thought, then.....NOW we step down the voltage instead.....Ready? (sorry it broke btw.....i thought lowering the amperage would help)

We need to add a Voltage Regulator to the circuit.....If the output from the Power supply is indeed 12 volts, then you should be fine. An easy one to find from Radioshack and such is a 5 Volt Voltage regulator. It's a little black square with 3 wires sticking out of it and it has a metal backing.

Now, because it's stepping 12 volts down to 5, it'll get a little hot, but that's what it's supposed to do. My advice would be to screw it to a sheet of metal, or another type of heatsink to keep it a little cooler. I would hope that 5 volts isn't too much for the wire.....

I also hope you have some more wire.... :/ sorry bout that...

I also went and looked at the giant 4-foot one that the aerospace department here uses, and I realized that the adjustments it made were for the amount of voltage going through it, not amps. So, we won't be adjusting the voltage really, but we'll step it down by more than half and hopefully that won't break another wire....

It's close to being done, so don't give up!

~Epyon
 
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bevbor

Well-Known Member
Epyon said:
Ah hah! Easier fix then I thought, then.....NOW we step down the voltage instead.....Ready?
Thanks a lot :)
Actually I think that right solution is to discard computer PS from circuit
and to purchase the Toy Train Controller.
It's amperage is 2A on output and it does change voltage very gradually.
But anyway, I appreciate each of your advices and waiting for new.

Best regadrs.
 
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Epyon

Jr Member
bevbor said:
Thanks a lot :)
Actually I think that right solution is to discard computer PS from circuit
and to purchase the Toy Train Controller.
It's amperage is 2A on output and it does change voltage very gradually.
But anyway, I appreciate each of your advices and waiting for new.

Best regadrs.
oo! That's actually a GREAT idea! I hadn't thought of that.... For that short of a wire, that'll be more than enough; and those aren't that expensive, either :D

Tell me how that works out! Good luck once again..

~Epyon
 
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