Making a Hot Wire Cutter for Shaping Foam

[@lawrencejones4329]

A little basic ohms law - 22g nichrome 80 wire is virtually 1ohm per foot, so let's say you're making a 3' wire cutter that's 3ohms, with a 12VDC power supply ohms law will give you the current, I=V/R (I current, V volts, R resistance) so - your power supply has to AT LEAST equal I amps. I amps= 12volts/3 Ohms........ so I = 4amps, so you'll need at least a 4amp power supply. If you want a shorter or longer cutter you can adjust it by either changing the supply voltage which pushes more current through the wire, or the gauge of nichrome wire which changes the resistance per foot of wire. The calculation remains the same I=V/R, and seeing as heat output is generally given in terms of power in watts, P=V*I so in this example Pwatts = 12volts * 4amps which gives you 36watt heater. You can look up the temperature characteristics of nichrome wire on the www but 4amps thru 22g will give you about 700degF, like this guy said don't mess around with other kinds of wire because you won't know what you're dealing with - for example if you tried to make one using 22g copper wire (0.015 ish ohms per foot) you would need roughly a 12V 250amp power supply and god knows what heat you would get from it, and something (perhaps you) will go bang. Nichrome wire is made exactly for this kind of purpose and is a known entity, so don't try making one out of copper, or guitar strings, or a shoelace. Be careful kids, don't burn yourself, and try not to burn your house down either.

[@АннаПономаренко-в9я]

P=V*I

[@StigDesign]

so true your comment always use multimeter if not sure the resistance in wire you have too, btw what wire is usually used on the old panel ovens the one that has mutiple wires that get hot and the oven is usually put on walls , i dont think they are wolframe type but :)

[@lawrencejones4329]

@@АннаПономаренко-в9я Ooops - of course you are right - typo, so have I edited it

[@ayyhmed]

Thank you for this. Very helpful

[@Ameen_AAA]

U r a legend

[@Jim-Wade]

Tip: You can salvage nichrome wire from the heating element in an old hair dryer or heat gun.

[@kaceesavage]

or an electric heater

[@Jim-Wade]

@@kaceesavage Yes, but most heaters I see today are ceramic, and the ones that have wires most often have heavier wire that won't work as well without more power, and they would not allow as detailed work as the thinner wire in something like a hair dryer.

[@joeymitchell3863]

toaster

[@Jim-Wade]

@@joeymitchell3863 Yep, but many today use a ribbon element instead of wire.

[@martvogt7019]

@@Jim-Wade twist it?

[@johnh1001]

After watching your video you've given me a fantastic idea ! ! ! At about time 6:00 you demonstrated "Detailed Cuts" . This is where the idea hit me . If you wanted to make detailed shapes in polystyrene to use as insulation for shipping container homes this would be fantastic ! ! ! Once the shape is cut out with your hot wire cutter it could be placed directly onto the outside or inside walls of a shipping container . This would then fill in that corrugated shape that all shipping containers have in their walls and insulate very well . Thanks for the inspiration .

[@FVBmovies]

There is a reason humans use wood, concrete, brick, mortar etc. instead of iron for walls. Do you know why cooling elements are usually from metals? If you have to use insulation for shipping container it's already useless for living.

[@gunsandhoses343]

I'm proud of you for using primer. That pipe will pass inspection and never leak!

[@onjofilms]

The portion of this video from 2:20 to 2:22 excited our whole family. Thank you for including this 2 seconds that gave unmeasurable pleasure to our entire family. (except for the ones in prison, they didn't see it yet.)

[@frieden6298]

bro what

[@maxpolaris99]

The possibilities for modification and upgrading with additional accessories are endless thanks to the simple and standard design!

[@verigone2677]

you can prestretch the nichrome, if you use a drill and those eye hooks you basically "unwind" the spring out of the metal and it work hardens. You can also double and triple up the strands to lower your resistance (let's you run lower amperage to a higher temp) also allows much more rigid structure to the cutting wire allowing you to create preshaped profiles.

[@jasonthurston799]

wouldn't lowering resistance allow you to get more current with lower voltage?

[@verigone2677]

@@jasonthurston799 yes, it does, but it also requires less source amperage to get the heat response you are looking for. It increases both maximum capacity and efficiency...at the cost of more heat and increase in danger. PRestretching the wire also reduces the sag deformity under load.

[@jasonthurston799]

@@verigone2677 How can lowering he resistance yield lower current and more heat? Could you show me the formulas you use to come to that conclusion? i always thought lowering resistance reduces heat if current remains the same or is lessened.

[@David-sw3on]

For a crude design- this was one of the best ive seen! Thanks for the great Vid, Im going to try this 👍😉🇨🇦

[@davidmcd8400]

Model airplane enthusiasts have been doing this for decades . Check out how foam wings are cut . A great addition would be a variable temp control for your cutter so you could use different length wires .It's a game changer

[@Ananimous7777]

Link?

[@davidmcd8400]

@@Ananimous7777 kzbin.info/www/bejne/Y6THYZZtjpaLp6csi=NeA2hPlwa0Q_6t5I

[@briansmobile1]

Thanks Chris! That was solid brother!

[@pinnacleroofing9841]

Look up "nichrome wire calculator" and there is a formula for choosing the Amps output on a power supply based on wire gauge, length, and voltage

[@noava]

what temp should it be?

[@rmdhn1]

@@noavaStyrofoam cutting temp

[@noava]

@@rmdhn1 ye, just go for max temp u can. the wire is gonna cool down when u go through the foam

[@grepora]

It is better to connect the power wire directly to the heating wire. Using the bolt to conduct the electricity will add resistance and cause the bolt to heat, possibly melting the PVC pipe.

[@woodfinchcrafts7267]

Resistance is inversely proportional to the cross section area of the wire (or bolt in this case). If the bolt actually got hot, the wire would melt long before that. The bolt has virtually no resistance in comparison to the wire. A 5mm bolt and 1mm wire means 25 times higher resistance from the wire

[@inktrooper.]

You could make a mounting rig to attach it to a table and work it like a band-saw. That would make your cuts more precise because you could use both hands to move the piece of foam, you could even make a sled similar to the ones made for table-saws for more precise and reliable cuts.

[@GoodRoads]

I'm definitely going to be using rigs and forms to get precise cuts, I was just free handing it here to see what the tool was capable of. Love the sled idea!

[@JasonGabler]

You made this comment for me :)

[@justadumbass5814]

Where can you buy the switch and power unit to build a larger hot wire cutter to cut styrofoam

[@martvogt7019]

@@justadumbass5814 thrift stores, restore?

[@PrincetonTV]

In stead of u-sing a bend melted in to the PVC we have been using a spring to attach one side of the wire to the Eye-bolty

[@antitheist9976]

Nice build mate, thinking of knocking one of these out myself for a while now. You simplified it, making it easy to follow, much appreciated. Subbed 🤩🙂

[@TesserId]

I think I'd prefer a momentary switch that would automatically turn if off if I let go (as a deadman switch).

[@joekaplowitz2719]

Thank you for this. I will make one one these fastened to a vertical wood panel. I need to cut a lot of 10cm in half by its thickness. By far the best way to do it. And no snow as with a saw or knife

[@MaxPower-vf8kt]

Thanks for the video. It confirmed what I thought about making one of these. I have an old hack saw I’m going to use as a handle. I plan on making a curve wire to cut what I need and plan on using a thicker stainless steel wire that I can be bent into a shape. My understanding is that stainless works well for this purpose, too. Have you tried it before?

[@GoodRoads]

Only steel guitar strings, which don't really bend to shape the way you're talking about. They _kinda_ worked but I had problems with them breaking a lot

[@Stetofire]

3:30 I just read today about tinned wires in sockets being a fire hazard. This is done in 3D printers often where they're tinned and assembled snug in the factory. However, tin tends to morph under pressure, so those joints will get loose over time even if they're not moved. Make sure to either get a crimp connection there or tighten them each time before use.

[@LongboardTechnology]

Its not that big of a deal here, though it is still good to be aware of best practices. I think its the thermal expansion cycles of the solder that causes it, and its a big no-no in manufacture, but here its really not a big enough problem to rush and replace the connection. Its also a hand tool, so its never used unattended, and not for hours of continuous use.

[@GoodRoads]

I saw that info recently in the 3d printing community too. I think in this case tinning the wires is probably better than having them bare, but a crimp-on connector would still be best.

[@LongboardTechnology]

Kind of more tangentially relevant here, but one of the KZbin channels I've started watching lately is Tim Hunkin and he's got this video he's recently put out on connectors as part of a series called "The secret life of components" kzbin.info/www/bejne/p2WWpY1sec-of6c Real broad base level, but well informed guide. Not exactly the same use case as you're likely to run into with your projects, but its pretty general. Might find some of his insights useful for revisiting your electric press for instance. More specifically to this hot wire cutter project, I keep a stock of 12v barrel plugs connectors. I never use the screw terminals, I always order pigtail connectors and solder them. I always think the screw terminal barrel connectors will be useful, but I ended up just throwing all mine out. But, as I said in my earlier comment, I don't think there's any reason to "fix" the connector you used here.

[@BillySugger1965]

@@GoodRoads No, tinning wires in screw connectors is really NOT the best solution here. The very best solution is a crimp-on bootlace ferrule, but few hobbyists have those. Instead just twist the strands together tightly and screw down onto the copper. That’s safe and will last practically forever.

[@MrOreo123]

Nice! I've been looking for a hot wire cutter, but reviews are hit or miss. Might have to add this to my build list, lol.

[@rbmwiv]

I have put a small spring on one side where the nichrome wire hooks up, it keeps the tension good without stretching the wire so much. I will have to build one like yours because what I have is setup like a miter box.

[@tedwingate]

Edge templates made from thin aluminum flashing make for precise repeatable cuts.

[@WolfPits]

I have had luck with card stock templates

[@robertwest9105]

thnx. been trying to figure out a decent configuration, the wall wart cinched it.

[@l.o.s.t9379]

Good evening bud, hope you have a wonderful day

[@frogicus]

I've used the same high "E" string from a guitar for years now . Still going strong . Nichrome is best but in a pinch .... 😉

[@RedEyedJedi]

Your way has a better pitch 😂

[@rchydrozz751]

E strings work fine. Get the right gauge.

[@sethforbis1114]

This is gonna work great for me! I only need it for one thing, to taper the edges of eva foam sheets to make prosthetic leg parts, im currently brainstorming a setup, that will cut 1/4 inch foam at a 15 degree angle, leaving just under an inch of tapered edge, something i can push sheets through quickly, like a router table, any ideas?

[@Muddytrickle]

Just because I always have some, could I use welding wire from my MIG? Also could the unit be powered by a battery charger set at 10 amp setting?

[@rustygibbs612]

Great two questions! Did you try it? Has anyone tried it?

[@christopherward4113]

How hot does this get and can I use it to cut PVC Trim board for my home's window trim - what is that/4 inch? Can I cut 3/4" board with this - I'd love to NOT have PVC sawdust everywhere.

[@AW-lc7tc]

could a thicker wire be used that could be bent to hold a shape and carve that?

[@edroush2009]

Good video, however connections section make it look like the red and black wires are twiested together so how does a switch work that is shorted at each end by twisting R&Blk wire together. Why? Unless for more current flow?

[@evilphantom457]

A good idea would be to get a piece of MDF plywood and make a a simple platform. MDF is preferred because it is very smooth and level. From there you would drill a hole in the center and just extend the arms of the cutter giving you more clearance for larger pieces of foam. Ive been messing around with the idea to make Halloween Foam Tombstones

[@iamski]

Not if you're working with large objects and sculpting.

[@Digmen1]

Wow that was brilliant, so cheap and easy

[@TesserId]

Love the back bow.

[@neiloler]

This is awesome, I was thinking I’d have to make some involved desk/table setup for a foam wire cutter, this is an excellent, and much for dexterous, solution. Thanks for making this video!

[@robertravena]

This may sound like a really silly question but do you put one wire to each eyebolt?

[@Purifiedinfire]

I basically made this today. I used 12v 5a Amazon ps 2 screw 12v adapter like yours 12g wire which might be to big but it's what I had. 21g 0.7mm nichrome wire Crimp eyelets with shrink sleeve. On the eye bolts. It will get warm but not hot. I could saw faster with the nichrome bow manually. Any recommendations?

[@InsectFromSpace]

does the hot metal not melt the PVC at the point where the wire is held by the nut and bolt?

[@cyrus7210]

Just asking because I could put it to use immediately. I've got some solid MIG welding wire on site. What do y'all think, could it work in place of the nichrome wire?

[@davebuchanan9761]

still working well? anything you would change?

[@jeffreymitc7256]

I made the hot knife as you outlihed in your video. I used a 5 amp power supply like you suggested and it heated up but only worked for a couple of cuts and then didn't heat up again. Checked all the connections. Any thoughts of why it stopped working?

[@johnwaldner743]

where did you but this roll of nichrome wire? I make my own hotwire cutters as well, and allways looking for wire suppliers

[@desertshadowspringers]

Forgive my ignorance but do the eyebolts not heat up enough to melt the pvc due to their being a larger diameter than the wire ? Do they get hot at all or is the heat concentrated only to the wire?

[@raeezmohammed2133]

I want to use it like a knife. How can we make one like that?

[@antennaist]

Nice video . Although I used a 3 amp DC output adapter and the wire was almost room temp. Could not cut anything. The cutting wire I used was .009 tungsten and thought that would be efficient enough to work , but I got no where.

[@SHADOW4301]

What gauge wire did you use? Did you like the thickness?

[@davidbrown6974]

What kind of wire do you use? Tried to make one but isn't working

[@augustestrellado1156]

Why does the 12 volts, 2 amps? Didn’t work well?

[@Thekrega]

Would the 2A supply work with a smaller gauge wire

[@garyrds]

Will this cut very firm seat cushion foam for furniture. I have 6" thick and want to reduce to 4" thick. They are 6x22x21and I want them to be 4x22x21

[@sanjuk2325]

Works well , but adapter gets too hot , any solution?

[@koelling]

Take an adapter with higher amps

[@217terrorhauntedhouse8]

What is the red/black wire (gauge) used? I have everything you used to make one except the wire for the switch and want to make sure I am using the correct wire, so it works properly.

[@stephengould9385]

what type of mask did you and what was the wire again?

[@EagleEyeProductionsLLC]

Have you had problems with the female adapter plug melting or going bad after a few uses?

[@pretotzkie4031]

does the end of PVC is not melting where the nichrome wire is attached?...

[@GoodRoads]

The hooked bolts that the nichrome is attached to really don't get that hot so the PVC doesn't melt. I'm not really sure why it works that way

[@WaveWasters]

I've been using welding wire for years to cut surfboard blanks, I can generally cut a few blanks before it breaks. But that nichrome wire look just that little bit easier to cut with. Have you noticed much stretch when cutting wide?

[@GoodRoads]

A little bit, but the flex of the pvc seems to be doing a decent job of taking up the slack. I'm sure the nichrome will burn through eventually too but it's working great so far and I've got a whole roll of it so it'll be easy to replace when it breaks

[@LightOverdoZ]

Google source: Nichrome, a non-magnetic 80/20 alloy of nickel and chromium, is the most common resistance wire for heating purposes because it has a high resistivity and resistance to oxidation at high temperatures.

[@66boogie]

Could you please list the exact material you used for this. Especially the wire gauges, amp of switch? Thank you

[@EricFeldmann]

an old hire drier can provide the wire as well and is easy to find and cheap

[@danielofarrill2494]

What’s the electric wire gouge ?

[@petersamios5409]

Try adding a foot pedal in addition to the switch. This is good when cutting intricate things where you want more control. Otherwise- great job.

[@floridadad71]

Could this work for shaving thickness of 1/2" off of a 4.5" thick memory foam mattress?

[@GingerWellyton]

Just finished making one of these but made like a bandsaw (moving the foam through the wire). An extreme fire hazard, but very helpful. Thanks!

[@brucemontgomery6853]

Will this cut foam rubber / as in for upholstery? Ty

[@justinemariano7190]

hello sir can you tell us about the complete materials you use through a message thank you

[@cbc_22]

Do I need to use a switch? Or can I just connect it without one?

[@jongkim8386]

Thank you for the video, helped me a lot!!!!

[@debashishdas4865]

What's the distance, voltage and current and swg of nichrome wire?

[@oby-1607]

Such a great tutorial. Better than using a tablesaw to cut foam.

[@TesserId]

I would have tinned the wire ends at the bolts. Spade lugs would have been nice too. Also, I'm trying to imagine what it would take to make the hot wire more of a flush cut. I think I might have gone to the trouble of taking a rotary tool to the bolt.

[@martvogt7019]

Double nut with two washers would solve any resistance problems here.

[@gregschafer7323]

Thank you, building foam mountains for HO train set

[@archangel6415]

Very helpful. I’m looking to making a hot wire to cut 200mm thick insulation foam down to 150mm thick. This is a denser type of foam than polystyrene! The panel widths are around 600mm wide. Imperial sizes 8 inch thick x 2feet wide sheets slicing down to 6inch thick if you see what I mean. My question is, can I use say the 200gm nichrome wire or you are using here or should I use something heavier? And the power source? I wondered if the I would need to use a larger power unit than the one you suggest. I had even thought of setting up the same type of frame and using a 3am fused plug in to the wall socket. I’m used to working with electrics. I’d be so grateful if you’d give me a help. Peter Glasgow Uk

[@GoodRoads]

I actually used this exact cutter to cut down some 2ft wide XPS foam for a failed project earlier in the year. I didn't have any problems with it at all, you just need to go a little slower since the cut is larger

[@gobigww]

Do you know if this would work with closed cell foam?

[@bretgreen5314]

Well done; thank you for sharing

[@howardnphyllis]

Can I use a Dremel speed control to control current and amps?

[@rchydrozz751]

If you're into RC hobbies. Electronic speed controllers will do the same thing.

[@iamski]

Can anyone explain how he wired everything together? I can't tell where the red and black wires are going it's so confusing.

[@SynergyAVE]

1:10 Whoops or did you mean to put glue on the inside of the pipe for some reason?

[@slodown3670]

Excellent demonstration. Thank you so much!

[@bukolsotes7107]

can cut a bed foam?

[@kenc3025]

How well does this wire cutter go through the type of foam that pool noodles are made of? (I think it's polyethylene foam)

[@ExperienceLife-hb1rw]

an additional option could be to incorporate a shop vac for fumes into the handle and drill holes strategically to suck in fumes where it's most like.

[@robertopellilli4749]

ciao scusa dove si compra questo filo x il taglio mi mandi il link grazie

[@davidav8orpflanz561]

I'm looking to horizontally cut a 10" thick 6' x 7', latex mattress in half (fillet style), due to the outer surfaces developing body impressions I hate sleeping in. Then I can put the outer faces into the middle and spray adhesive glue to join them. The trick is, not to cut the pieces with waves, but perfectly flat for a level sleeping surface. Why do this? California King size Natural latex foam mattresses cost $3,000 USD! So, if I can just "resurface" this mattress this way, eliminating body impression sides, I can get another 10 comfortable sleeping years out of this mattress - for the cost of making a cutter about 7' wide, and keep the overall original width too. So, I'm thinking of using wood to make one of these, a 7' long piece of wood (2" x 4" x 7')(and attaching a wider flat thin piece ofmterial to the 4" side, to it for guiding (i.e.: 1/4" x 24", x 7'), which can make the cutter lay flat and even, keeping the cutting line flat and making a 5" deep straight and flat "Fillet" cut from start to end, as I advance it over the top of the mattress (lying on a flat surface) - kind of like a planer works on wood - except in this case the planer is the moving machinery, and work-piece (Latex mattress) is stationary. Thus, I'll use springs to make the nichrome 80 wire taught, that way; why I need an extra 1' wider than the mattress width, room for the springs beyond the width of the mattress. I already have tools, hardware, and power supplies (might need 8 minimal to 10 or > Amps for a cutting wire so long). If sure AMAZON has the nichrome 80 wire, eh! Maybe I should make a video,eh?

[@tothelighthouse9843]

Ugh, I found my way to this vid because I also need to cut my talalay latex mattress horizontally, lol! Have you undertaken your project? If so, what kind of results did you get? I'm not very handy, so this project might be a bit beyond my skill level. I'm considering trying a 39" fine-tooth bow saw blade to see if I can just carefully saw the horizontal cut. Cheers!

[@davidav8orpflanz561]

@tothelighthouse9843 I haven't done it yet...I was thinking about doing it this way. Mattress lying down on adjustable bed-base. Place a 5" (1/2 matress thickness) wide board on each parallel, lengthwise 2 side of the mattress. Cargo rachet straps to keep boards in place. Then I can run a hot wire cutter along the top of the boards, as a guide...like a bread slicing guide.

[@tothelighthouse9843]

@@davidav8orpflanz561 Yeah, I'm trying to find a good way to cut mine horizontally. Please definitely update here if you do decide to proceed! Love to know how it went. Cheers!

[@Saidkomil]

Hi there. What kind of metal is the heating wire

[@paulmarin6380]

i need to cut out the shape ofa guitar pick in foam so i can insert the pick in the hole, and then makeput the pick inside the foam in display case. The thing is I cant cut out the foam cleanley. Any advice?

[@dragonfire2371]

Hey man, dunno if you can help me out here, i got the same 12v 5a transformer as you and the same gauge nichrome wire, but my wire wont heat up, what is the lenght of the wire you used?? Thank you. Nice vid btw im trying to follow ur video to make my foam cutter.

[@GoodRoads]

Mine is just about 24" and a longer wire will give more resistance so (I think) it would heat up better. I really don't have my head wrapped around the way resistance works though

[@XianTC6]

I’m running into the same issue as you. I’m getting 12 volts across both hooks (with out the Nichrome wire). I did notice a blinking green light on my power supply, it should stay solid. I think my power supply is shorting itself hence the blinking light

[@dragonfire2371]

Well, it is solved, i noticed the wires i got for transmitting electricity didnt have that much copper and were creating enormous resistance. I switched to wires with more copper and i had to make the cutter longer beacuse it was heating up the nichrome wire way too much xd

[@XianTC6]

@@dragonfire2371 Can you please link me to the new wires that you got? I’d appreciate it

[@billgowland3250]

Bow locks Just heat an old bread knife on a gas ring. Works a treat. You soon get the hang if it With practice.

[@nb3channel]

Good project. Reduce the length of your cutter (nichrome wire) to half if you want to use that 3A adaptor.

[@fredmcveigh9877]

does it work on sponge?

[@davidski9331]

Thanks, this looks great. I'm planning to make this with some modifications to make it bigger to cut a king sized mattress to thin it and resize it. Do you think this will work for that as well using the same voltage (5V) or should it be upped if that's even safe.

[@cedriceveleigh]

At 3:19, you shouldn't tin the end of wires when clamping with screw connections. This is a known safety hazard because the tin will creep (cold flow) causing the connection to become loose.

[@elisa7joy9]

Does the Nichrome bend easily?

[@didoivanov6292]

so basically you just short the + and the - with a wire?

[@thombarlow5977]

I FABRICATE AVIATION COMPOSITES, COULD YOU LIST THE PARTS. YOU USED IN THIS VIDEO, THANK YOU

[@mikesrcgarage]

Nice multi tool! Lol! 🔥🎶 Seems simple enough to build 🤔 lol! Dig your decks on the wall ✌️😎👍

[@madmanmechanic8847]

Cool video dude

[@heathcwalker]

That was awesome!!

[@krustysurfer]

Great video! Thank you!

[@vivienhall1468]

Would this work on spray foam insulation

[@onddu2254]

Does the cutter need more volts or amperes if you make the wire longer?

[@henrir4362]

Hmm.. thanks for the video. Is it volts or amps that cut the the foam... I found several laptop adapters laying around at max 2.5A, but at 24-48Volts. I assume a laptop charger should have plenty of juice to heat the wire, no?

[@GoodRoads]

Huge disclaimer here: I DO NOT understand electricity. That said, my wire wouldn't even start to heat up until I stepped up the amperage in the power supply. I read that sometimes if the power supply is rated for a lower amperage they're programmed to recognize the power draw from heating the wire as a short circuit and automatically shut off to prevent fires. Which is a good thing! Unless you're actually trying to get your wires really, really hot

[@BiduscoIKUmar]

Is the Ampere that do the work

[@martvogt7019]

@@BiduscoIKUmar multiply amps by voltage.

[@martvogt7019]

This is the voltage and the amps while it is on.

[@martvogt7019]

This equals watts, which is heat.

[@selfsameday7448]

Very satisfying

[@MRSTU1210]

Good stuff subbed