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Old Feb 19, 2013, 04:34 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,779 Posts
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Hot Wire Power - And more questions

What are you guys using for wire-cutter power supplies?
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Last edited by schrederman; Feb 20, 2013 at 10:38 PM.
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Old Feb 19, 2013, 09:34 PM
Spy's sappin' my thermal!
Chris Sutton's Avatar
Seattle, WA
Joined May 2009
137 Posts
I have two that I use.

One is a Duratrax ICE battery charger. It has a motor break-in mode dating back to the days when you needed to break in brushed motors before using them. It maxes out at 8 volts, by .1 volt increments, and also has a current readout. Not quite enough voltage for bigger bows, though.

The other that I have is a router speed control (http://www.harborfreight.com/router-...rol-43060.html or similar) and a 24V, 6A transformer. It has two drawbacks: I can't turn the voltage down low enough to run my smaller bows, and it's easy to accidently flip it from 'variable' to 'full power' which makes quick work of .016" wire. A lower-voltage transformer would solve both of those, but I got the 24V one dirt cheap.

Were I shopping for a new charger, I'd probably get on of the IChargers from ProgressiveRC (http://www.progressiverc.com/chargers/battery-chargers) and have that double as my foam cutting power supply. They have a foam cutting mode that supplies up to 25V and 10A, which would cover my needs and probably quite a bit more.
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Old Feb 20, 2013, 12:22 AM
Dean
A10FLYR's Avatar
USA, CO, Littleton
Joined Apr 2005
3,876 Posts
Quote:
Originally Posted by Chris Sutton View Post
The other that I have is a router speed control (http://www.harborfreight.com/router-...rol-43060.html or similar) and a 24V, 6A transformer.
.
That and an automotive battery charger with a "start" setting.
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Old Feb 20, 2013, 06:30 AM
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ron gijzen's Avatar
Liempde, Netherlands
Joined Jul 2007
150 Posts
I simply use the 12V car battery that I also use for my whinch.
For a 0.3mm NiCr wire you get the correct current when placing the clamps on the wire about 2 feet (50-70cm) apart.
Simple & safe
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Old Feb 20, 2013, 08:49 AM
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Joined Oct 2006
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For cuts up to two feet, I use an old computer power supply to get my 12V. For cuts shorter than 20", I use an LED dimmer switch http://www.amazon.com/LEDwholesalers...dp/B003L4KKF2/ to drop the power. When I found a setting I liked for a given length of cut, I simply made a line on the dial. I had a multimeter on it at one time, and I think I needed 0.45 watts/inch, but that was with my specific wire/foam combo.

Don't worry too much about your power source. Make it safe, adjustable, and repeatable, and you'll be fine. There are a million different ways to dump power over a wire, and there really isn't much difference between any of them.
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Old Feb 20, 2013, 09:43 AM
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David Forbes's Avatar
United States, FL, Gainesville
Joined Dec 2005
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Cheap and available, works great.
Dave
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Old Feb 20, 2013, 10:10 AM
"...certainty is absurd."
kcaldwel's Avatar
Joined Jan 2007
3,601 Posts
The transformer from a rechargeable drill charging station is usually 18VAC or so, which works well. If you are like me, you've had a few drills die and have left over charging stations. I just take out all the recharging electronics, and connect directly to the transformer outputs.

I have a couple of old ones that put out 12VAC from 9V drills, which is about right for my blocking bows without any adjustment.

Kevin
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Old Feb 20, 2013, 10:29 AM
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David Forbes's Avatar
United States, FL, Gainesville
Joined Dec 2005
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Transformers from halogen lights are usually 12VAC, don't require modification. If you've got a junk box you probably have something that will work
Dave
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Old Feb 20, 2013, 01:27 PM
Registered User
Milwaukee G Mitchell, Wisconsin, United States
Joined Mar 2002
757 Posts
Some newer battery chargers have a foam cutting option. I know my iCharger does.
But I use an Astro 110D charger. Simple current adjust with digital display.
Nobody seems to listen to me on this so if you want more info you'll have to ask.
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Old Feb 20, 2013, 04:33 PM
Whisper Model Aircraft
heliwill10's Avatar
Greensburg, PA
Joined Feb 2008
558 Posts
If you wanna get real nuts and have something plug n play:

http://www.mastechpowersupply.com/dc...3a/prod_2.html

I use it on my CNC and it controls the kerf very well. You can set a constant amperage or voltage. Overkill for a bow, but still handy in the long run.

Will
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Old Feb 20, 2013, 10:02 PM
Hot Dawg Glider Pilot
schrederman's Avatar
United States, TX, Weatherford
Joined Nov 2002
7,779 Posts
OK... Thanks for the replies... I have a 12VDC - 10A power supply that I use with my battery charger at home. I think that will work. I made a foam cutter many years ago that would cut tapers. I was cutting up tp 48" in white foam with .020 safety wire.... but only used it once. With the blue and pink foam, what's the max recommended length of panels I can cut... and stay pretty accurate. My intention is to bag my male wing plugs and make female molds from them, for a 166" span glider.

Thanks, again...

Darth Composite Noob... AKA Jack
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Old Feb 20, 2013, 11:44 PM
I DS slower than I build!
Cory's Avatar
Idaho Falls
Joined Jul 2006
2,348 Posts
I built one of these: http://www.charlesriverrc.org/articl...amcutterps.htm It works great.
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Old Feb 21, 2013, 06:48 AM
Live and let Fly !
Lawrence B's Avatar
Mill Hill - London
Joined Aug 2009
107 Posts
Built a modified version of the schematic shown. main diffrerances;

higher a.c. voltage to drive enough amps to cut 'blue' foam
addition of switchable ballast resitors for long / short bow operations.

it works just fine

LB
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Old Feb 21, 2013, 11:22 AM
Whisper Model Aircraft
heliwill10's Avatar
Greensburg, PA
Joined Feb 2008
558 Posts
Quote:
Originally Posted by schrederman View Post
OK... Thanks for the replies... I have a 12VDC - 10A power supply that I use with my battery charger at home. I think that will work. I made a foam cutter many years ago that would cut tapers. I was cutting up tp 48" in white foam with .020 safety wire.... but only used it once. With the blue and pink foam, what's the max recommended length of panels I can cut... and stay pretty accurate. My intention is to bag my male wing plugs and make female molds from them, for a 166" span glider.

Thanks, again...

Darth Composite Noob... AKA Jack
At 33" with a .033 wire I use 1.95amps and my voltage is around 27-31 volts. I can't cut much more than that....

Will
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Old Feb 21, 2013, 01:40 PM
I DS slower than I build!
Cory's Avatar
Idaho Falls
Joined Jul 2006
2,348 Posts
Quote:
Originally Posted by Lawrence B View Post
Built a modified version of the schematic shown. main diffrerances;

higher a.c. voltage to drive enough amps to cut 'blue' foam
addition of switchable ballast resitors for long / short bow operations.

it works just fine

LB
But don't use nicrome wire.
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