GRJ GGG someone please help with hot wire cutter table I built it wont work!

hi I would hook up a (vom) volt ohm meter to dc volts I'm  assuming that's what the circuit uses, power the unit on and read the voltage, then leave the meter hooked up and turn on the hot cutter full on and see if the voltage drops I would guess the power supply you are using can't handle the current in amps that's what I would suspect your problem is. look on your power supply and let us know the amp n voltage rating in volts n amps ok and well go from there ok

Glad to help you in any way I can

Alan

p.s. send me an email with your phone number and ill call, you or you can call me.

check YOUR EMAIL

If the power supply works with one cutter its probably not a power supply problem. Use an ohmmeter and measure the resistence of the cutter that heats up. Then compare it with the one that doesn't. The resistences should be within a few ohms of each other. I suspect there is a bad connection in the one that is not heating. The wire is nichrome. I assume the wire gauge on both cutters is the same or close in diameter. 

Pete

I'll throw it out there that even a low end computer power supply will deliver about 15 Amps on the 12 volt line, and a quality one can put out 60-80 Amps.  It may just be that a 6 amp supply isn't enough.  

JGL

The resistance of your Nichrome wire heating element (cutter) will vary based on it's gauge (diameter) and length. Wiretron provides technical data in tables.
It could be that the wire you used on the table is the wrong gauge, or maybe it is too long.

As an aside, I believe postwar Lionel used 34 gauge Nichrome wire in their smoke units.

     I just spoke with Alan (Repair Technician) and I need to get a voltmeter and another power supply. I went back and looked at You Tube videos and the power supply I have is not big enough in the hot wire kit to work on the hot wire table I made. I thought it was 14 volts 6 amp but it is 6 volts 1500 mili amp. I have been having computer issues so in going out to get a volt meter and power supply I am taking my computer to get it worked on. I will post my update on this issue as soon as I get my computer back (next day or 2). Thank you everyone for your help! I will take pictures of the hot wire cutter table and post them on the other thread I already started when I get the computer back. Choo Choo Kenny  

FWIW, I have the Hot Wire Foam Factory scroll table and I power it from my test bench Z1000 with a 2A circuit breaker in series with the leads.  I set the voltage to around 10 volts, and I've never tripped the breaker.  It cuts through 2" pink or blue foam like butter.  The stock wire is 10.5" long and it's cold resistance is 6.2 ohms.  Obviously, the resistance goes up substantially at higher temperatures.

     Well live and learn! I found out through trial and error that you can not use a AC dimmer switch with DC power. GO FIGURE! I know have a 6, 7.5, 9, and 12 volt 2.5 amp power supply from Radio Shack. On 6 volts it would not heat up enough to cut the foam. On 7.5 volts it just barely would cut the foam. On 9 volts it cut the foam a little faster. On 12 volts it disd pretty good but you have got to watch. In moving the 4X8 sheet I hit the wire and it broke. I now use kids glove care when cutting the foam board so I don't break the wire again because I only have enough wire to replace it one more time before I need to get more. Thank you everyone for your help and suggestions. Choo Choo Kenny

Useful information first:  

I'm not sure what size wire your cutter uses, but if you are looking for a local supply for kanthal wire, you could try local electronic cigarette store, one of the ones that specializes in e-cigs/vaping.  Most good vape stores will have 50'-100' rolls of kanthal wire in stock in various gauges between 24 and 36.  Prices are usually fairly reasonable.  

Less useful information:  

The reason your light dimmer won't work for DC is that it uses a part called a Triac, (properly called a Thyristor), to produce the dimming effect.  This rapidly turns the power on and off to make a lightbulb see a lower effective voltage.  The light dimmer sort work will for incandescent light bulbs, but are not good for most other AC loads, as they are 'dumb' devices and have no circuitry to determine what part of the AC sine wave they are turning on and off for.  As to why they only work on AC, a triac can not be turned off once it is triggered until power stops flowing through it with AC this is not a problem, as the power turns on and off 120 times a second.  With DC, however, the power stays on, so triacs are fairly useless for DC power.  

JGL

I have to ask what kind of wire you're using as well.  I have the Hot Wire Foam Factory that I've used quite a bit, I just connect it to a transformer and crank it up until it cuts at a nice speed.  I'm still on the original wire, I've had it for a couple of years.

     I bought the wire from Scenic Express in Delmont Pa. (it is just out the road from where I live). The wire is .121 from Woodland Scenic and it came in a 4ft. length. Choo Choo Kenny

The wire on the Hot Wire Foam Factory scroll table is .01" in diameter.  Wire .121 diameter would take a LOT of power to heat up!

.01 wire is 30 gauge, if its nichrome 80, its 6.5 ohms per foot.
.121 wire is close to 8 gauge (.128 diameter) and is  not even on the chart I am using. The closest they have in the table is 10 gauge, which is .06248 ohms per foot.

Wiretron

Yep, the 11" of nichrome wire on my unit measures around 6 ohms cold.

For cutting stryrofoam nichrome is preferred over kanthal wire. Not sure why as they seem to have similar characteristics like ohms/ft and maximum temperature.

Read more here.

http://www.temcoindustrialpowe...?p=cutting_styrofoam

Pete

     Here are some pictures of what I am doing. Choo Choo Kenny

If you run out of wire, use a guitar string.

What would a guitar string do for you?  It's steel, and much too low resistance to use for a foam cutter.

I made my own foam cutter using a hobby transformer and a guitar string an it worked great.

Must use some serious current to heat that guitar string!