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how to make home made foam cutter for slicing foam Answered

I dont have much electric knowledge ,but i have to make home made electric foam cutter for my kid ( he has to make some school project ) by cutting / slicing foam . i have pen type soldering iron / room heater etc. shall i made foam cutter from it , can i make room heater coil directly connect to steel wire to make it hot.please guide me ,it is very urgent .?



Best Answer 6 years ago

This is simply the very best foam cutter ever made
by Dave Spencer


U can also use Car or bike battery

U can do anything, But to do neat cuts u will want to adjust for a current to match your HOT wire be it a Ni-Chrome wire or Welding Rod. Regrettably I did not record the voltage just the current.

Now my variac was set at 65 where the 85 setting represents line. Math ratio of 115/85 = output/65 delivers about 88 VAC which is then reduced by Stancor Transformer delivered 8.8 VAC to my weld rod wire.

This means a 12 VDC car battery would dangerously over heat the wire.

Any one reading this suggestion should be careful and perhaps use a larger diameter of wire to uptake the higher voltage and current from a car battery.

Be sure to click the pic to see the whole image.


How old is he. It is unusual for a teacher to set a project that requires special equipment.

Foam can be easily cut with a bread knife, sand paper will smooth it off.

If you really want to make a hot wire cutter you need some Nichrome wire (an old electric fire can supply) About a foot or two.

A spring to keep the tension as the wire heats up. and some plywood to make the frame.

use a 12 volt car battery NOT the mains supply

i dont have 12 v. battery , kindly guide weather possible by 220 volt AC supply ,as commen in india. i have tried by pen type soldering iron ,wrap copper wire around it ,but it not working .

in your above dig. you have show that + and - connect directly to Nicrome wire.it will work , i think it will shortcircuit ?

No not 220 volts you will kill someone.

Yes Nichrome wire has a high resistance so depending on how long it is it will get hot but not short the battery.

In general these things draw a lot of current (that's why they get hot) so using a car battery is sensible.

Using mains is a recipe for severe injury.


i will go for 12 volt , ( by using transformer )

shall i use Room heater coil ( as Nichrome wire )

Ones again thanks

I doubt the homework was set to require a hot-wire cutter. More likely the task is "make an X, to your own design".

What kind of foam are they cutting? (i.e. soft foam like used on a bed, or styrofoam)

Does it have to be a hot wire cutter or is anything acceptable? How old is he? Are there any safety considerations that need to be addressed?

It would help to have some more info...

thanks dear ,
he is 9 years old , he has to cut thermocoal pieces for his project , he will not directly do the foam cutter ,i will make it for him.and take full safety measures.