DIY Hot-Wire Power Supply (Vid 2 of 2)

This is video 2 of 2 in my short series showing you how to build your own inexpensive, reliable, and safe power supply for heating the hot-wire for your foam-cutting equipment.

Here is the parts list for items used in this build:

MUST HAVE ITEMS:

From Radio Shack...

Enclosure (8"x6"x3", #270-1809)
Transformer (25.2v, 2 amp, #273-1512B)
Bind Post (#274-661)
Banana Plugs (#274-721)

From Lowes...

Lutron Dimmer Switch (#D-600PH-DK)
Nuts and bolts, or rivets for mounting components

Additionally...

An old AC power cord (2 or 3 prong) with appropriate plug

Optional Parts I Recommend (from Radio Shack)

Fuse Holder (#270-364)
Fuse (250 volt, 2 amp, #270-1023)
120 volt Neon Lamp (#272-0704)

For more information on this project, tune in to TheCrashCast podcast (in iTunes, or at www.TheCrashCast.com), episode #82.

EDIT: A lot of people are sending me emails asking me technical questions about this design. Please note that I am NOT an electrical engineer and my knowledge in this area is quite limited. Following are the links to information that I based my design on:


http://www.instructables.com/id/Hot-wire-foam-cutter/

http://www.charlesriverrc.org/articles/tools/joedydruliafoamcutterps.htm


http://www.utahflyers.org/index.php?option=com_content&task=view&id=37

Now if you want a power supply with LOTS of power, and have the savvy to build it, then I highly recommend your building one of these:

http://www.nsrca.org/technical/tip_tricks/foam_cutter/foam_cutting_power_supp...

I have one of these and use it for all of my wire lengths about 28".

Category:

Science & Technology

Tags:

• Hot Wire Power Supply
• Foam Cutting
• PhlatPrinter
• MK3
• MKIII
• TheCrashCast

[tenminutetaxi]

Sir you saved my hot wire cutting project. Not only did you provide a comprehensive way of building a power supply, but you taught some of us to fish! I can't thank you enough.

For any of you doing this project. I have NEVER wired something like this before. I followed his instructions in both videos and got it all right the first time!

Thank you Crash!

[CrashHancock]

@tenminutetaxi Congrats on your success! I am so happy to have been able to lend a hand, my friend.

[Dblnut08]

I've searched and searched video after video and finally I've found your expertise. You have a great presentation style and a very direct and no non-sense outlook on construction techniques. Keep up the good work!

[CrashHancock]

@Dblnut08 Thank so much! I spent years training people in the professional arena and sometimes those old ways come back. LoL Just trying to pay the hobby back a little since there were so many great people around helping me when I was young.

[jpurcha]

I constructed this box as shown except, I used a 1 Amp fuse instead of a 2 Amp fuse. As I slowly turn it up the dimmer, the light glows than turns off. Yup, I've blown the fuse. I'll try the 2 Amp fuse. Is 2 Amps enough adequete?

[CrashHancock]

@jpurcha A 2amp fuse is all that I have every used. I figured it would be the best choice since the transformer is rated at only 2amps. The goal is to blow a fuse before frying the transformer. ;)

[eduardoescareno]

one word...AWESOME!!! I already purchased my supplies and I am ready to start building.  Thank you sooooo much!

[letsflyrc1]

my transformer made a buzzing sound and than a pop then dident make any sound at all did i break the transformer????

[letsflyrc1]

what is the wire called that has the male banana connecter??? i really need to know i got everything else built and i dont have that wire

[VJExavior]

Thumbs up for clean wiring job, heat shrink, fuse, and layout.  Well done sir!

[brewmiester11]

Great video; one minor correction however. The black lead on the secondary is not a neutral lead it is a center tap which will give you half of the rated voltage if you use it with one yellow lead, in this case 12.5 volts. When I'm not using the center tap, I cut the stripped portion off and coat the end with liquid electrical tape.

[CombatSpread]

@panther3002 I got it from a local hardware depot called B&Q I think it was only £8. It works a treat. Can you a long or short wire with it.

[panther3002]

@CrashHancock Again Crash, thank you very much for the video. I am happy to have a nice hot wire foam cutter now, & I don't mean any offense by my many comments to make a few corrections. I certainly could not have even began to do this without you, but once I got started, & burning things up, I kept pushing for over a month till I had figured it all out & measure the currents with a multimeter, tried dozens of different fuses, & bought a dozen different types and sizes of wire. Again, thanks!

[panther3002]

@13Amped Very good estimate. I wish I would have read your comment and bought a multimeter to test my setup before burning up 2 transformers, a switch, and 10 fuses. Just a minor correction though. According to the back of the new transformer packaging, in the bottom right corner, in tiny font, and oddly enough, only in Spanish, it indicates that the input current is actually 0.760 A max and the output current 2 A max.