How dd I make a hot wire cutter?

[John Busby]

Hi all
Not sure this really the right forum! but its the closest we have
does any one have information on how to make a hot wire cutter for cutting foam.
The commercially made one I have is to small for the job at hand.
I know I need nichrome (Spelling) wire.
But how do I make the cutter? and keep tension in the wire without breaking it??
regards John

[tangerine-jack]

HOT WIRE .... Parts List -
#1 ... Ac or Dc - Model Train Transformer ( 12 to 18 volts output at 2 - 4 Amps. ) Most any train transformer will do, including similar Power Transformers with variable Ac or Dc - outputs. Purchased or Scrapped from your parts, that meet required Voltage & Amps.
#2 ... Dowel Wood - Rods = ( Handle & Bow ) making parts of 1/4" & 3/4" Dia.. Rods NOTE ... Make the Bow and Hand Wand to the widths you require, to cut any size foam. Usually a ni-chrome wire stretched between the bow - ends, that's 2 1/2 feet wide - at most. Works fine for most any job you'll use this system for. As for the Hand Wand, it should be a U-shaped - short piece of nichrome wire, about 4 inches in length = between the forks of the wand. Then before use, shape the wire to desired shapes for carving jobs, then turn the power - On and gently start carving.
#3 ... Nichrome Wire Sources = Hobby Shops or Hobby Suppliers = A resistor wire that heats up, to cut or melt Styrofoam.
#4 ... Two Scrap pieces of Brass Tubing, used to make - heat insulators to avoid the wood dowel rods from being burned by the nichrome wire.
INSTRUCTIONS FOR USE ....... Set your Transformers - voltage settings, at the lowest voltage setting - First. Then turn the system - On. Slowly increase the voltage until the "Nichrome Wire" starts to smoke and heat up. Testing the heat settings on a piece of scrap foam - First, before you start cutting anything, adjusting the voltage setting accordingly. WARNING .... Never set the voltage higher than is needed to cut your foam, Slow & Smoothly. The wire can be easily - Burn Out and will break apart and easily injure you or someone else!

[John Busby]

Hi TJ
Thanks
I found one described on the internet it was an H frame with the cutter wire in the bottom
of the H and a tension wire and and spring in the top of the H your thoughts would be appreciated.
thanks for the warning and highlighting it red so I would not miss it.
the small one in your sketch is about the size of the one I have nichrome wire has been found in fact that was the easy bit[:D]
regards John

[Cthetrains]

if it was me, I'd just get a longer piece of NiChrome wire, and re-shape the handle to the desired width..the power requirements shouldn't be much different than the original....

[John Busby]

QUOTE: Originally posted by Cthetrains

if it was me, I'd just get a longer piece of NiChrome wire, and re-shape the handle to the desired width..the power requirements shouldn't be much different than the original....

All well and good but unfortunately the original one which I bought is 4" max cut
and I need at least a 3' long cut it just isn't going to work that easy
regards John

[RhB_HJ]

QUOTE: Originally posted by John Busby

QUOTE: Originally posted by Cthetrains

if it was me, I'd just get a longer piece of NiChrome wire, and re-shape the handle to the desired width..the power requirements shouldn't be much different than the original....

All well and good but unfortunately the original one which I bought is 4" max cut
and I need at least a 3' long cut it just isn't going to work that easy
regards John

John,

Did you say THREE FEET??

OK here's my suggestion: use two separate handles and tighten the wire by hand i.e. pull on both handles, if necessary with two people!

Amongst a whole bunch of other cutting fixtures, I have one like that. Works like a charm but the arms get tired.
BTW I don't use Ni-Chrome wire, I use spring wire that can be bent to different shapes and holds them!

Of course my ResSolder/HotWire rig also has approx. 400W capacity and the secondary voltage is only 8V i.e. lots of ummph!

[John Busby]

Hi RhB _HJ
Yes I said three feet it needs to be that big for cutting Row cottage and terrace house walls much easier to build 1/2 a street side
at a time for terraces and the entire row for cottages.
regards John