Introduction: Making the Mighty Goliath Hotwire Machine!

Picture of Making the Mighty Goliath Hotwire Machine!

Complete instructions for the making of the Mighty Goliath Hotwire Machine. Materials and directions are shown in each step, image notes. See my other instructables for sample work, signs, etc. Creativeman.

Step 1: Additional Instruments Made With Same Technique

Picture of Additional Instruments Made With Same Technique

I have made several instruments like this, namely to use in a class I plan to hold. I think it is a viable art form and is relatively unknown to the general and artistic community. People find it hard to believe you can get such detail in the lettering. Try it, I think you will like it. Disclaimer: IF YOU DON'T UNDERSTAND THE ELECTRICAL WIRING, DO NOT ATTEMPT! GET QUALIFIED ELECTRICIAN TO HELP. I have used one of these machines for 15 years with no problems, not even a broken wire. So if things don't seem to be working right, you have probably done something wrong. A few additional tips: Try to keep temperature as low as possible. You want to melt the foam, not burn it. Use only with adequate ventilation. Some people may be sensitive to the vapors produced. Use care around the wire! It is hot and will burn you. Don't let young children play with it. It is not a toy.

Step 2: Pieces of Project Needed to Constuct Instrument.

Picture of Pieces of Project Needed to Constuct Instrument.

Most pieces of the instrument assembled together for this instructable. The transformer, dimmer control and wires will be added in the next view. View image notes for a complete explanation of the various parts.

Step 3:

Picture of

Electrical components needed for the machine. All items are listed in the image notes.
Costs: Electrical cord: $1.25; Transformer: $6.90; Dimmer switch: $4.99 (push on/off type); Nichrome wire: I bought 100 feet for $2.50! Wood parts probably add a dollor or so to costs, same with various mounting screws/hardware. So for between $10 and $20 dollars you can have your own hotwire machine. I have seen these on the web for much more money. This machine will accomplish the same thing. I have made larger machines to be able to cut larger pieces of styrofoam, or EPS foam. I just changed the length of wire, the transformer and the sizes of the wood components, obviously.

Step 4: One Example of a Dimmer Control

Picture of One Example of a Dimmer Control

In this picture, an inline lamp dimming switch is shown. It seems to work ok, although has not been tested over time. This type of control is quite a bit more expensive than dimmer switches used in other models.

Step 5: Closer Look at Arm Assembly

Picture of Closer Look at Arm Assembly

This is a close up of one arm made for the blue machine. All are similar. These two pieces are made of common pine lumber, 3/4 inch thick. The arm it self is about 8 inches long by 3/4 by 1/4in. Pieces are glued and screwed for strenght.

Step 6: Apparatus for Testing Various Components and Wiring Details

Picture of Apparatus for Testing Various Components and Wiring Details

This is a helpful item to test transformers, switches, wiring, etc. before final assembly.

Step 7: Details for Mounting Dimmer Switch.

Picture of Details for Mounting  Dimmer Switch.

Shown in the pictures are the milling or routing of a depression for mounting the dimmer. Placement of dimmer and knob are shown.

Step 8: Bottom Mounting Piece Details

Picture of Bottom Mounting Piece Details

In this shot, details of the bottom wire mounting piece are shown. A 1/8 inch hole is drilled in the end of the wood piece to accept a 8-32x1in. machine screw. To this screw, the power wire from the transformer and the hotwire itself will be attached. In the center of the bottom mount, a 1/2 inch hole is drilled with a forstner bit. A 1x6in. wood screw with washer is used to attach the piece to the table. By moving the mounting piece slightly in any direction, hotwire can be adjusted to be plumb in two directions and give right angles when slicing through the foam.

Step 9: Top Arm Details

Picture of Top Arm Details

Here, the top arm has been drilled to accept the machine screw as shown. The hole is 1/8 in, and the machine screw is an 8-32x1in.

Step 10: Cutting Stencil for Painting on Name

Picture of Cutting Stencil for Painting on Name

A stencil is made by selecting the fonts used on the word processor, printing the words out in duplicate, and then cutting the stencil with a craft knife, or scalpel.

Step 11: Making Design Decisions

Picture of Making Design Decisions

Shown are various instruments being tested for color combinations, placement of components, lettering choices, and so on. See image notes for more details.

Step 12: Completed Instruments, Ready to Go to Work

Picture of Completed Instruments, Ready to Go to Work

Many hours of creativity lie in store for the craftsperson who has one of these. Enjoy!


CaptCheryl (author)2017-02-09

Awesome job Creativeman. Do you sell these machines? Do they take 110 or 220 electric? I'm sending you a message.

happyclayton made it! (author)2016-05-01


Just wanted to say a big thank you for posting this. I've now made one using your very helpful design information (largely included in the image annotations, for those who missed them.) I've not made it as pretty as you, and I've made some modifications relating to the materials I had around and some ideas I liked, but I'm pleased with the results. I tried using a scavenged transformer from some powered speakers initially (mains to 20V), but it "popped" after about 1/2 hour of use, so I resorted to buying a 6V one with a decent power rating for about £7, and that seems to be working great.

I've used the cutter to make a custom transport case for my (home-made) 250-size quadcopter, out of some foam (that came as packaging for a laptop trolley at the high school I work at) and and old blow-moulded case that previously held a wheel lock. That seems to be working great, too!

Once again - many thanks! I'm sure it is going to get lots more use in the future.


Creativeman (author)happyclayton2016-05-01

Thanks for your comments and I'm glad you made use of the instructable and the instrument. Many projects can be made and you've demonstrate that! Very useful.

numanair (author)2011-06-22

Couldn't you use flat screws here?

jayeshshinai (author)2011-04-05

is it possible for this machine to help me cut MDF?

randomray (author)2009-02-05

Good gravy , it's a great IDEA for an Instructable but you don't say how to do anything .If this is how your classes are going to be taught you are going to have disappointed students and you are going to be frustrated .A simple wiring diagram and a picture of how to make the frame is all you needed .Two steps , less showing off the " Mighty Goliath" . At least you tried to share .

Creativeman (author)randomray2009-02-05

See step 6. (and quit whining). Cman

shazni (author)Creativeman2010-11-13

I'm new to this so please bear with me.... I live in asia the power voltage is 220V....could i just wire the whole thing up to a ac adapter which has adjustable voltage like 3v . 4.5v . The adapter says PRI :AC 220V 50/60Hz , SEC: 3-12v 600mA. I don't need a dimmer and Transformer right? cause i haven't the faintest clue in how to do that. I've read some use batteries.... so could this work? what voltage should i use? 4.5V or 6V. BTW no one here knows what nichrome wire is....( could be cause we talk a different language) what can i use as an alternative? floral wire?. Please give me an answer. Thank you

jaydeechick (author)Creativeman2009-02-06

Perhaps because I am a female, perhaps because I have blonde hair, perhaps because I live on the other side of the globe, perhaps perhaps perhaps.... I cannot figure out what to do with this Instructable. Is this a prefabricated kit?? Step 2. What size is the base board? What size are all the pieces of timber? What is each piece of timber for? Don't really care that they were cut with a band saw. Steps 3,4 & 5 are nice. Which order do I attach things, and where, and how? Step 6 I can see what you're trying to show us, I just think it's done poorly. Step 7 I suddenly need a router Step 8 is as clear as mud to me. And when was I supposed to attach the transformer? Step 9 What is the best method you've used to get flat edges on a screw and then drill a hole into it? Or is it a prefabricated item? Step 10 is a total waste of time so far in any attempt at this project, nothing has been put together yet? Step 11 another useless step when I can't figure out the first 9 steps Step 12 Your natural coloured machine shows the transformer on the top. Is that were it's supposed to be mounted. I appreciate the effort you've gone to with this Instructable, however, alot of it is more about what you (creativeman) can do, rather than clear instructions which would allow anyone else to build it. I have carefully read every word and looked at every picture and read every note on the pictures, and I am still none the wiser. Finally, how do I attach the wire? do I just twist it on and hope for the best?

randomray (author)jaydeechick2009-02-07

There is much more information in some other Instructables just type in " hot wire foam cutters "when you search . There are at least three more that are helpful .Read the comments also , because there is more help there also .Then just make one that will be the right size for your project .

randomray (author)jaydeechick2009-02-07

You really took the time to give a good critique jaydeechick a lot of the stuff can be made whatever size you want . I'm sure you can use whatever tools you have at hand . I just wish he told us a lot more about the electrical stuff .While he means well it's just not helpful .Maybe if we post it on the Forums an electrical hacker can help us out . By the way I learned long ago not to underestimate a blond female regardless where they're from and the pretty ones you have to watch the closest . Now creativeman is going to tell us we are whining because we noticed there are problems

AndySavage (author)Creativeman2009-02-06

How is that helpful at all?

jb510 (author)2009-07-02

Wow this looks cool, but this instructuable really needs some work on instructing. #1 Where/how do you run the wire from the transformer up to the end of the top arm? #2 Why did you flatten the screw for the top arm? #3 Why did you router out a space for the transformer? #4 How did you put the bottom adjuster together and how do you adjust it? This looks so useful and cool but from the this instructable I have NO idea how you did it. #5 It appears you put legs under it. Yes it's rather obvious but it's still worth putting as a step in an instructable. I'm really trying to avoid ranting, but have to agree with many of the above commenters... There is not one single photo of the completed wiring let alone the connection details. Frankly there are not any instructions given in most of the "steps". You could replace "steps" with the word "photo" and it would be more appropriate. If you just wanted to post a bunch of photos of cool paint jobs for hot wire cutters use Flickr. To end on a postive note however this is a great looking hotwire, just wish you would fill in some of the details on how you built it and cut out some on how you painted it.

stringfellow (author)jb5102010-08-29

I'm thinking that if you can't figure out most of this stuff on your own, Really you probably shouldn't even be considering this project, also you might not want to be such a critic unless you have posted your own ibles. They post the comment below as a reminder (We have a "be nice" comment policy. Please be positive and constructive with your comments or risk being banned from our site. )

Morganbarker (author)2010-05-10

 Where'd you source that transformer?  I've been using a car battery charger and it's just a little too much.  I know some people use doorbell transformers, but they're usually about 12vac and 10 amp.  Still a little big.

SparkyOR (author)2009-11-27

Not to be too much of a worrywort, but I think adding a fuseholder would be good on the input, and mounting the dimmer and transformer inside of enclosures to keep little ones from getting the shock of their lives. Or even big people with messy workbenches.
But I like the project, might have to do one!

omnibot (author)SparkyOR2009-12-11

Actually, most dimmers are fused so that takes care of that mostly but I agree that it needs some better enclosure.

Sarjex (author)2009-11-27

This is a great instructable.  If I were going to mod it in anyway it would be to create a grid on the base to help insure straight cuts.

joshua1277 (author)2009-09-19

what gauge is the wire ?..

superhubbardman (author)2009-07-22

what sort of transformer is it? and whats the wire nut

irfree (author)2009-07-04

I'm gonna beg to differ. I think Cman did a fine job. I suspect that if I couldn't tell from looking at the components how it works and how to put it all together I probably shouldn't try to build it. In fact I'm confident I could build it and operate it from the information supplied. I used to teach public speaking and would only allow two questions in critiques. What worked and how could it be made better? I'd recommend that approach. We will get way more information that we can use. What worked. The photography is very good. The examples of the work Cman produced with this is inspiring. The branding that he has done is also part of the instructable, note that he calls it an "instrument." What could be made better. An upfront disclaimer like "This is a dangerous tool. It has the potential to injure you. I'm not going to show connections, because if you don't know what you are doing you will almost certainly injure yourself." I'm goin out in the garage and build one. It will take me longer to assemble the parts than it will to build it.

srmousse (author)2009-02-05

Since Creativeman is so unwilling to talk about wiring, just take a look at this Instructable for a better idea of how the wiring works...

I know a lot about electrical wiring. I wired the majority of my house and it hasn't burned down... It even got a seal of approval from the inspector. But it would be nice to know where you have intended each of these components to go.

Instructables are intended for the DIY'er to LEARN a little bit more then they already know, so that when they attempt to DIY their own project, it's not as much a mystery.

Thanks for giving us mystery. Thanks for enabling a desperate DIY'er to injure themselves and others when they mistakingly place the dimmer switch between the cutting wire and transformer instead of between the wall outlet and transformer... Or when they use the Nichrome to wire the dimmer switch to the transformer and the standard wire to attempt the cutting... Or when they buy a dimmer switch that is not capable of handling the electrical load.

The fact is, Leaving out the wiring diagram, not to mention the construction of the entire project, is more dangerous for the average DIY'er than sharing the diagram. Imagine giving a gun to someone and not telling them about the safety switch, or how to load the ammunition cause you don't want them to hurt someone.

I mean honestly, you spent more time talking about the "look" of this device than on how it works, or even how it all comes together.

Here, look at this pretty gun, it has a black trigger, a nice dark oak handle, and the words "Remington" carved on the stock... have fun with it. Oh, and if you have never handled a gun before, have your local gunsmith load the ammunition for you.

snowpenguin (author)srmousse2009-03-04

There is a diagram! What;s the problem, then? Jerks.

srmousse (author)snowpenguin2009-03-05

No problem, it took several of us posting for CMan to FINALLY upload a diagram... see my post below... "My Goal was not at all......"

snowpenguin (author)srmousse2009-03-04

You two are jerks, you know that? It's obvious that CreativeMan put a lot of work into this instructable, and instructables don't always have to show you exactly how to build something. Many I have seen are just show-and-tell, and this one is meant for people who know pretty much what they are doing. Great way to ruin the whole page.

srmousse (author)snowpenguin2009-03-05

My Goal was not at all to be a jerk. The fact of the matter is, at least three people asked specifically for a wiring diagram and all three times CMan said "Please see step 1. Cman". So when you refer to step 1, you find: IF YOU DON'T UNDERSTAND THE ELECTRICAL WIRING, DO NOT ATTEMPT! As I said before, I do understand electrical wiring, and I was able to build a very nice cutter based partially on this 'ible, but mostly on others. I will say Thank You CMan for the idea behind the frame, that was a big help in making my cutter a LOT more stable. The problem is, I feel that leaving the wiring diagram out does more harm than good. The fact is, a curious DIY'er is going to attempt this with, or without a warning or enough information. And these people will know just enough to seriously injure themselves or others. By giving all the information, at least they will know "how to put it together". I understand my statement may have come across very strong, I tend to build strong arguments long before I am willing to speak up... The point is, regardless of the influence of my post, CMan did, in the end, upload a wiring diagram. And that, my friend, has gone a long way in my opinion in making this 'ible useful.

Creativeman (author)srmousse2009-02-05

See step 6.....Cman.

snowpenguin (author)Creativeman2009-03-04

Was there a diagram on step 6? If so, it is gone. P.S. Great 'Ible! I love it. I'm going to make mine like this, just on a larger scale...

Creativeman (author)snowpenguin2009-03-04

Thanks Snow: the diagram is faint but it is there....look closely! Good luck with your project. Cman

snowpenguin (author)Creativeman2009-03-04

Wow... Can't believe I missed that... Hey, you seem to be an expert on hotwire, and I have a question. I have some 24-26 gauge wire (I believe nichrome, but I'm not sure...) from a toaster that I want to make into a larger version of this. It's going to be a foot long... I've experimented with different voltages; 9v DC, 12v DC, 24v DC, and even... 120v AC!!! That last one was pretty stupid, I have to admit... It got so hot the wire actually broke into 3 pieces... So, my question is, what is best? Low voltage, high amps, or high voltage, low amps, or a combo? AC or DC? I believe DC, but hey... I'm a beginner... Someday in the 2000 year range I'll graduate to CNC, but this is what I've got now...

poolgirlblue (author)srmousse2009-02-11

I totally agree. This isn't an Instructable, it's a "Look what I did!" It's an awesome tool and i think it's a great concept, but compared to how much information is available in a real "Instructable" (Instruct, as in, give directions how to) i don't even understand how this became "featured". Great job on the machine Creativeman, but the actual instructable, with the exception of your pictures, is very poor

cbrown222 (author)2009-02-14

probably a stupid question but where do you get transformers?

snowpenguin (author)cbrown2222009-03-04

Radioshack, old electronics, etc.

kathyh239 (author)2009-02-05

Has anyone used this to cut cardboard? Do you think it would burn/start on fire?

chrwei (author)kathyh2392009-02-09

I think it would either be ineffective, or start a fire. a strait-edge and a razor knife is still the best way to cut cardboard

Creativeman (author)kathyh2392009-02-05

? Not what the machine is for. DONT GO THERE! Cman

chrwei (author)2009-02-05

You seems to have skipped the wiring. Did you use the center and one 6V off the transformer and wire that in series with the dimmer and nichrome wire?

Creativeman (author)chrwei2009-02-05

Please see step 1. Cman

chrwei (author)Creativeman2009-02-05

I'm not really sure how that's an answer. I do understand wiring in general and understand that what's actually going to work is going to depend a lot on the actual wire used, I just want to know what seems to have worked best for you. I think the entire point of the Instructables is to share your experiences in making something. I also think that if you go ask a professional electrician how to do this he'd tell you that you are going to burn your house down and just go buy a commercial cutter... after all just being a licensed electrician puts some legal liability on him. You've given your disclaimer, why are you afraid to share?

chrwei (author)chrwei2009-02-09

I see a pencil diagram has been scanned and uploaded to step 6.

tjhart85 (author)chrwei2009-02-09

The author doesn't seem to want to instruct anything. His instructable would be great if this were a pre-fab, but it doesn't seem to be. He's not showing anything useful at all. He took pictures along the way to show off his skills, but he doesn't tell you what's going on. I guess he's assuming that you already know what you're doing & want help with the look/design? I guess, the people taking his class may already know pretty much what they're doing & he'll point them to this instructable as a reference?

James Haskin (author)2009-02-08

I think this is a great instructable. Some people want specific dimensions so they cant screw it up but I think this was great. Good job.

Creativeman (author)James Haskin2009-02-08

Thanks Mitch. Cman

Culturedropout (author)2009-01-25

Is this a dimmer meant to control the speed of a ceiling fan? The "lamp dimmers" used to smoke if you hooked them to an inductive load (like a transformer).

netbuddy (author)Culturedropout2009-01-31

If the transformer is rated 6VAC at 1 Amp then the dimmer switch you use must be rated well above 1 amp and able to use 6VAC.

If your using a light dimmer switch, these are very small loads. The rheostat is whats important. Think you would need a wire wound type as these carry more current.

static (author)netbuddy2009-02-07

6V @ 1A is 6 W. Even with considering a transformer isn't %100 efficient, most hardware store light dimmers should be up to the task. I need to scroll back up and reread the instructable, as it seems that some design considerations weren't covered or I missed them.

southseas (author)2009-02-05

I'm living in Australia and wherever I ask, noone's heard of nichrome wire. Does it go by a different name down here than it does in australia, or am I asking at the wrong places?
Try talking to someone at a company which supplies PS foam, they use wire Hot Wire Cutters to slice large blocks into sheets and break their wires regularly.
You'll either get some for nothing, or maybe in exchange for a slab of cold beers.


netbuddy (author)southseas2009-02-06

Try looking for "Resistance wire" that is used in thing like base board heaters, cooker elements and so on. Nickle Chromium wire is also another name (hence Nichrome wire)

Marsh (author)2009-02-06

Nicely done, but where do you get Nichrome wire? Around here the guys at the electronics supply just give you a dumb look when you ask for a transistor.

junits15 (author)Marsh2009-02-06

from taosters, the heating elements inside them are nichrome there is thick wire and thin wire in most toasters.

About This Instructable




Bio: Retired, doing art work now. Great. Have the time and the money to spend doing what I want to do.
More by Creativeman:How to Make Fairy Doors/Fairylands and Open Up a Whole New World!SKULL STAND(S) FOR BUDDING ARTISTSThe Art Of Reclaiming Oak Flooring:Upcycling Shop Workstand
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