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Old Mar 30, 2009, 03:36 PM
Yummy cheese
enduro_man996's Avatar
Earth
Joined Mar 2009
285 Posts
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My easy home built hot wire foam cutter

took me about 5 minutes to make... and cost nothing... Of course I had to rob the batteries out of my mag light...

here we go.

-4 D batteries
-coat hanger / insulation wire / (springy used to hold up insulation in rafters, great for landing gear too) music wire... what ever
-1 paint stick
-black tape
-speaker wire

I bent the insulation wire, put loops on both ends... glued it to the paint stick... attached the batteries and wires with hot glue and black tape... pealed some speaker wire... took one strand of wire tied it through the loops and BOOM SMACK WHA LAA basicly a super simple heat element.

foam cutter it works awesome! How did I do it before? this is crazy fast and accurate!

Hope I helped some one out there who didn't want to pay 10 - 20 bucks for a foam cutter...

Now I think I will make a nicer looking one... maybe hook it up to a computer power supply I have laying around... hummmmmm



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Old Mar 31, 2009, 12:33 AM
Yummy cheese
enduro_man996's Avatar
Earth
Joined Mar 2009
285 Posts
no posts must mean I am the last one on the block to have a hot wire foam cutter... I am soooo behind the times... I guess thats what I get... for not makeing it chrome plated cnc with a digitally ballasted salt water flashing array of aquious film forming foam (AFFF), compensated by ducati 996 v twin noise offseting device to detract from the utter coolness of the carbonfiber......... Ok I'll shut up.....
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Old Mar 31, 2009, 03:23 AM
1400 watt RW Zephyr
matwelli's Avatar
Taranaki New Zealand
Joined Sep 2003
1,333 Posts
Hey bud, I like it ! nice and easy, wild build one myself. I built a table top cutter, but a hand held like yours will be very usefull
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Old Mar 31, 2009, 05:16 AM
When I fly, Birds attack
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Aveiro, Portugal
Joined Jan 2008
135 Posts
I like it to simple and efective

I'm building one using Legos eheheheh
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Old Mar 31, 2009, 09:51 AM
Yummy cheese
enduro_man996's Avatar
Earth
Joined Mar 2009
285 Posts
Legos

Quote:
Originally Posted by Giedi_Prime
I like it to simple and efective

I'm building one using Legos eheheheh
Legos! legos are awesome... I bet that battery holder tube that comes with some of the technic stuff would work great... to hold the battery and mount / glue the wires too.

I was absorbed in legos as a child... I even had them at school in jr. high... and got to progam them to do what ever with old Apple IIe's

O sorry for the flash back.
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Old Mar 31, 2009, 12:06 PM
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Joined Mar 2009
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I'm new and I don't want to rob the thread, but I have been looking at foam cutting tables and power sources for a few days now. I see lots of options. I have a question for you guys. Let's say time and money aren't important, but it has to be DIY. Why wouldn't a nice DIY AC to DC power supply be a good way to go?? Say 0-24 VDC out put at say up to 5-6 amps...??? Could be used for other things as well. Really not much to it and it would sure me from blowing transformers.

Thanks

cwood3
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Old Mar 31, 2009, 12:15 PM
Foam Fighter and a Bloody Mick
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Hermann, MO
Joined Jul 2008
386 Posts
How come everytime I try to throw one together it doesn't work? I set up a pistol grip soldering gun as my transformer, and I can't get any wire hot enough. The one here is just using copper speaker wire for the cutting element? Don't you need more resistance than that? What if I hook up my 12vdc 6 amp power supply into a dimmer switch (the supply runs off of 110VAC, then converts it). Would I be able to get variable temperatures without killing my supply?

Please help, the table I built is awesome, but I can't get the danged wire hot!!
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Old Mar 31, 2009, 12:31 PM
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Like I said, I'm new at this, but I have established 1 thing. You want to use a higher resistance wire. Copper has low resistance, hence, it's use in electrical circuits. The wire of choice seems to be ni-chrome, but I have been testing with piano wire available from hobby shops and even solid guitar strings. I just saw a 24vdc, 6.5-amp power supply on the net for $25. I just have to wonder if it is a "smart" device that has shut-down or overheat safety features... I bought a battery charger yesterday, and it obviously does. Dang it. Guess i'll try my last 120/24 vac, 2-amp tranny with a triac circuit. Lemme know how yours id going.

cwood3
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Old Mar 31, 2009, 12:50 PM
When I fly, Birds attack
Giedi_Prime's Avatar
Aveiro, Portugal
Joined Jan 2008
135 Posts
I built a foam slicing sistem using a power suply that I salvaged at work. I can connect the wires in diferent sockets providing me 18 or 24 volts at about 3 Amps (If I recall correctly ). The wire I use is a Ni-Cr 500Watt coiled resistance and I stretch it up for about 70cm (the boards that I cut are 60cmx120cm Dow blue foam). It works like a charm

For my small table mounted cutter I use a normal transformer

I'll post pics soon
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Old Mar 31, 2009, 01:09 PM
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mico_gc's Avatar
Slovenia
Joined Jun 2006
56 Posts
Hello,

It is always good to have a hand held foam cutter laying around
I am using electric guitar string and it works fine. Only drawback is, it corrodes after a while... but it is not a big problem.
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Old Mar 31, 2009, 01:54 PM
Foam Fighter and a Bloody Mick
grenadapult's Avatar
Hermann, MO
Joined Jul 2008
386 Posts
Quote:
Originally Posted by Giedi_Prime
I built a foam slicing sistem using a power suply that I salvaged at work. I can connect the wires in diferent sockets providing me 18 or 24 volts at about 3 Amps (If I recall correctly ). The wire I use is a Ni-Cr 500Watt coiled resistance and I stretch it up for about 70cm (the boards that I cut are 60cmx120cm Dow blue foam). It works like a charm

For my small table mounted cutter I use a normal transformer

I'll post pics soon

Tell me, Harkonnen, what do you consider a "normal transformer"? LOL!
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Old Mar 31, 2009, 11:00 PM
Yummy cheese
enduro_man996's Avatar
Earth
Joined Mar 2009
285 Posts
Quote:
Originally Posted by cwood3
Like I said, I'm new at this, but I have established 1 thing. You want to use a higher resistance wire. Copper has low resistance, hence, it's use in electrical circuits. The wire of choice seems to be ni-chrome, but I have been testing with piano wire available from hobby shops and even solid guitar strings. I just saw a 24vdc, 6.5-amp power supply on the net for $25. I just have to wonder if it is a "smart" device that has shut-down or overheat safety features... I bought a battery charger yesterday, and it obviously does. Dang it. Guess i'll try my last 120/24 vac, 2-amp tranny with a triac circuit. Lemme know how yours id going.

cwood3
well, this is what I know.... no matter what the wire is made out of... assuming that it is conductive... the thinner the wire the less amps / volts / magic space dust... it takes to heat it up... I am using really thin speaker wire... and it cuts like a dream... If I go up to a little thicker wire... it cuts like a butter knife through an over cooked steak. (not very good)

If I want to run thicker wire... I need more space dust....


or D batteries... they are cheaper ne way...

One last thing... if I put too much tension on the thin wire it just snaps... but at the right tension she purrs like a two dollar... in do a to the

hehe
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Old Apr 01, 2009, 03:25 AM
When I fly, Birds attack
Giedi_Prime's Avatar
Aveiro, Portugal
Joined Jan 2008
135 Posts
Quote:
Originally Posted by grenadapult
Tell me, Harkonnen, what do you consider a "normal transformer"? LOL!

You got me


one of these cheap things that I got at a chinese store


Long live the Baron!!
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Old Apr 05, 2009, 12:03 PM
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White Rock BC/Blaine WA
Joined Apr 2007
595 Posts
I'm building a hotwire cutter this weekend and I really like this design. The simplicity of it is... impressive. My question is, how do you keep tension on the cutting wire? Most other designs I have looked at employ some type of spring of elastic to keep the wire taunt as it will expand when heated.

For you other guys to clear things up... as I understand it you can basically use any kind of wire you want as your cutting wire, the thing is the more conductive the wire, the more amps you are going to have to use to heat it up. The difference is a lot, copper wire will take something like 20 times more amps than a stainless steel wire will so if you can always go with the stainless. It is also true however that the thinner the wire the less conductive it will be, and a longer wire will have more resistance than a shorter one. The best option really appears to be 'nichrome' wire. It is designed to be used in heating elements so it will not stretch as much when it heats up. One last point; do not use galvanized wire, it gives off some toxic fumes, speaking of which use you wire cutters in WELL ventilated areas!

Thanks for the cool design!
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Old Apr 05, 2009, 12:45 PM
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Joined Nov 2006
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Only problem I can see with that is when you have to replace the batteries. Foam cutters use quite a bit of power and after a couple plans you will need to change the D cells, that will be quite costly in the long run. I used a car battery charger for my power supply. Wrap some wire around some non conducting items (I used glass stands use in sign construction) and move the aligator clips accordingly to reduce/increase temperature of the wire. Ultimately, if you don't have any of this kind of stuff on hand, it would be cheaper to go buy the foam cutter.
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