DIY Hot-Wire Power Supply (Vid 1 of 2)

This is video 1 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 (also 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

[MrBurchillb]

Do you have a part number for the transformer you used. My radio shack rep thinks they don't sell transformers.

[CrashHancock]

@MrBurchillb Please see the description under the video for all part numbers. :)

[tab1257]

Thanks Crash, THANKS, I think I'll have to build one of these.

[CrashHancock]

@tab1257 You are quite welcome! I've got some more cool things like this to share as soon as I can free up enough time to get them filmed.

[chinaclipper1]

Great job Crash! This should meet my needs perfect. I would suggest you put a picture of the schematic you link to on your online presentation. I gotta tell you, once I had that other guys schematic (you actually link to it) it was easy.

Thanks amigo!

China Clipper

[fireflies355]

Looking at similar transformers, the advertized max (2 amp) amperage rating is for the center tap with half the advertized voltage (12.6). Therefore when using 25.2, Volts I would think you only have 1 amp rating. Hence the power (Current X Voltage) is constant. However If it’s working well who gives a……

[noxnflame]

I was looking around and the Transformer serial is incorrect. The correct one is

Model: 273-1512



[p3x197]

Do you think a 12v tranformer will work?

[MedicDillahunty]

Great project! I built one of these last night in a little over an hour and it cost me about $30. Works great! I'm using 30ga Nichrome on a 48" bow, and it gets plenty hot. Makes very nice cuts in EPS. Even at 48", I can't put full power to it or it deforms the wire. Probably could drive 60" of wire without a problem. Thanks for the great video!

[earlsplanet]

I tried downloading this video for future references and couldn't, but I think that I probably be able to download it

Earl

[lloydheins]

I may have missed this but do you know an approx cost for the build? Thanks Crash

[panther3002]

(5/5) Also, I'd like to note that after burning up 2 transformers,a switch, & about 10 fuses, as I bought my 3rd transformer, i noticed it was in different packaging. On the back in the corner, in tiny font, in Spanish (I'm bilingual), it indicated a 2A OUTPUT current and 0.760A INPUT current. That's how I found out the true currents. When I was pulling 13A on the output side, the input was pulling <2A,hence the fuse never blew, & my transformers overheated instead. This was using 19 gauge wire.