Hot-Wire Foamcutter (Battery Powered)

I have a hand-held battery powered foam cutter (these can be found at any hobby/craft shop). I find it quite useful, however I'm quite often frustrated by its inability to do detailed work. This instructable is simply a tabletop flat bed version of this handheld unit.

Features;

-Makes detailed work easy.
-Inexpensive (only a few dollars in parts)
-Small (easily storable)

Lets get started;

Step 1 Parts & Tools

Here is a list of the parts I used. Many of these can be replaced by easier to obtain equivalents, or cheaper options.

(also the metric components can be replaced with their nearest imperial counterpart if you are in Canada or America (M5 = 5mm ~= 1/4")

Parts: (Approximate cost $15)

-Bolt (M5 x 30mm) x 2
-Nut (M5) x 2
-Washer (M5) x 3
-Bolt (M3 x 15mm) x 2
-Nut (M3) x 2
-Washer (M3) x 3
-Nut (M20) x 4 (these are used as legs to lift the board off the table so 4 chunks of anything about 15mm tall will work)
-Nichrome Wire (can usually be found at hobby shops beside their foam cutters as a replacment part)
-Battery holder (2 x AA)
-Small Cutting board (mine was 16cm x 26cm)
-Wire (about 40 cm)
-~40cm of 4mm diameter metal rod

Tools;

-Pliers
-Wrench
-Hot Glue Gun
-Solder
-Soldering iron (I used a soldering iron to melt the holes into the cutting board this is because I did not have access to a drill)

Comments

[craig3]

Do you think a 15V DC phone charger would do a good job with sometihng like this?

[jayeshshinai]

can i use an old nokia charger (3.7-4.5) volts to heat up the wire instead of spending on the batteries?
coz batteries are costly and a pain to dispose off..

[craig3]

I'd also like to know this, I want to make one for my tafe prob workshop.

[cooldudeintown]

Looks like your a fan of the movie the Manhattan project , Well that's just how it looks . Nice instructable

[possum888]

Just curious, how well would this do for cutting bread/toast?

[noahh]

It would work just as well as trying to cut bread or toast with wire. The reason it cuts foam is because it's heated, not because it's sharp. Hope this keeps you from some frustrating work!

[tictaclad]

i have an idea..much easier. make a rig 2 hold the wire veridically. make it a few inches long for more flexibility. then take a torch and heat up the wire...problem...solved

[printman]

How long can 2 batteries keep the wire hot enough?

[Zaphod Beeblebrox]

were do u buy foam sheets like that

[macrumpton]

I wonder if using larger capacity batteries would make them work longer and destroy the batteries less. I have made a similar thing using a 6v lantern battery.

[khang_ho]

Hi Clement, One more question, where can I buy a battery holder? thanks, - KH

[macrumpton]

Radio shack

[brandonssk]

you can get them for Free from Keyelco.com Thats where I get my Battery holders and stuff from.

[Riversmith]

How do you go about getting these from Keyelco.com for free? How is it they don't make you buy them, or do you just request a single sample? Thx!

[brandonssk]

yes, you just go to the website, and there should be an area that says "free samples" Once you find what you want you need to put the part number in the box and then fill out the shipping info, then they send it to you :) I've only requested 2 samples at a time but i think you could go as high as 4 if you want.

[Riversmith]

Thx for the quick response, I wasn't sure that I would get one with the post being from February of last year! Thanks Again!

[jjay10]

go to radio shack

[TheMadScientist]

erm.? wow.

[tichus]

Oh, the 'rubber' that I was referring to is actually a clear RTV type product.

[tichus]

You could also add a type of adhesive rubber bumper used for the back of picture frames (or to keep cabinet doors from slamming) to the bottom of the 'nut feet' to make your board slip proof. They are usually sold in small sheets of about 30 at hardware or crafts stores. I put them on all kind of things that I want to stay put or give a little extra stability to.

[madwilliamflint]

So what I don't understand is, why doesn't thin gauge copper wire work? I tried something like this and ended up just exhausting the battery pack in record time. I took a single-strand out of a multi-fiber cable and made the final bridge with that. Any pointers on where to find the bridge between theory and practice on this?

[GnomeMaster]

wouldnt this heat up the battery making it explode?

[madwilliamflint]

I was wondering that myself. My guess is no, as he built and uses the thing. But my electronics knowledge is thinner than it ought to be.

[smokehill]

Excellent idea -- back in the 50s we used to use model train transformers to cut plastic, usually to "modify" plastic car or plane models. Our parents would have ****** if they'd seen us, of course, since the wire we put between the two screws would glow red-hot and could be really dangerous. It's amazing we ever survived childhood.

It took us some experimentation to find the right wire size to make the train transformer cut well without burning out the wire, though.

This is the same principle, and a great Instructable.

For larger work, like foam rubber, I used to use old electric carving knives I found at yard sales. It also worked great for fiberglass insulation batts when I built my first house.

[mman1506]

thats why transfomrs now have fuses\

[smokehill]

They're taking all the fun out of childhood. What's the point of being a kid if you can't risk life and limb every day ... not to mention the fingers and eyes of your friends? Somehow we all got through our childhood in the 50s with monster firecrackers, firearms everywhere, helmetless bike-riding .... We might save a few kids from bad accidents with all these nanny-state laws, but I'm not sure it's worth the tradeoff. Perhaps Darwinism works better, where the unfit get weeded out early.

[madwilliamflint]

Huzzah! In my adulthood (well... while getting older anyway) I'm actually starting to recapture a lot of this. Now I can get or make the good stuff :)

[Shadowfury]

Yeah, these new laws make life really dull for minors. You can't legally play with mercury or hydrochloric acid anymore, at least in the U.S. and U.K. I can't buy anything science-related without suspicion anymore. Ever since the terrorist attacks, I can't even take a soda on to a plane. It's ridiculous how paranoid people are about these things, especially chemistry. The problem seems to be human nature. Humans fear what they do not understand. In a panicked effort to evade any possible cause for injury, the government made everything deemed hazardous illegal. Despite the fact that millions of people grew up around these substances with no side effects. I like playing with mercury, and will continue to do so. I think it's ridiculous how paranoid everyone is, especially when it comes to chemicals. As soon as an average person hears the word "chemical" they think of poison. When they hear the word "radioactive", "Uranium", "Plutonium", "Radium", "radiation", or "nuclear", they think of bomb. It's because of all the crap the government has been spoonfeeding their people for years. It's the reason children no longer have the ability to experience high school chemistry class, or mix some acids and bases and watch the foam bubble up, or even something as simple as rolling a bead of mercury around a bowl and watching it all coalesce at the bottom. It all comes down to people's ignorance to the unknown.

[DIYmaker96]

I concur, the fun in science is constantly being watered down by lawsuits. LEGAL PLEA "I didn't know the H2SO4 would burn my throat if I drank it!" Coming from a 13 year old, chemistry sets state that the "coolest" experiments are the ones that use only hot water and food coloring! Even then it requests that you have a parent around. My point is that black powder, sugar rockets (very fun), or making your own crystal iodine, may soon become tantamount to heresy. The only risk I see in this experiment when exercising common sense is benzene inhalation. Who knows? Maybe tomorrow we will need a license to own a screwdriver.

[mman1506]

yah i know when i was little i would hide in my room making sparks for fun but coundnt make a wire hot it just goes click and you have to wait 10 minutes for it to reset itself

[MarkFW]

How quickly does this drain the batteries? Any idea how hot this wire gets? Reason i'm asking is im making a solar/battery powered grill for camping using heating elements and need to know what these are.

[jpatano]

you can replace the nichrome wire with some metal electric guitar strings if you have some spares laying around. i have something similar i use that i built with a guitar string element. took a little trial and error finding the right gauge wire for my application. (i'm using a 20 V battery pack from an old cordless drill as a power supply) I found that the "D" string (the smallest stranded string) works quite well. It still gets hot enough to do the trick, and it's heavier construction means you won't have it burning out quickly. with a lower voltage power supply you could probably use the smaller gauge wires for better detail though.

[Pyro the maniac]

How hot does it get? would it slice through 1/8th inch diameter rope?

[triumphman]

DO NOT BREATHE THE FUMES IF THE FOAM GETS TOO HOT. THEY ARE VERY TOXIC AND CAN CAUSE PERMANENT DAMAGE TO YOUR RSPIRATORY TRACT! PROVIDE VENTILATION , EVEN A SMALL COMPUTER FAN TO BLOW THE FUMES AWAY FROM YOU. BEST TO VENT THIS TOXIC STUFF OUT OF THE AREA. THANKS. LIFE IS TOO PRECIOUS AND SHORT. THINK ABOUT IT!

[DIYmaker96]

Called Benzene A CARCINOGEN I do admire your safety with projects. But this can also be equally a risk with soldering and welding, yet we take necessary precautions SO WE DONT HAVE TO WRITE IN ALL CAPITALS

[GnomeMaster]

wouldnt this heat up the battery making it explode?

[cbrown222]

unitednucear.com click chemicals and metals, get thick or medium for this and if u need neodymium magnets thats the place to get them too

[ShampooRobot]

nice battery drainer

[awang8]

It's doesn't really drain the battery... Nichrome has a high resistance... It's not really a short circuit like most people think.

[Rick make sit]

does the wire get hot only because of the current or did you had to you a resistant how much volt is the baterie (English not 1rst language)