woodworking needle files

for this project i’m going to show you howto make a hot wire styro-slicer that cuts styrofoam shapes with precision and control.it’ll produce professional looking 3ds props for cosplay or metal casting, as well as makefoam fighter jets, that actually fly across the room. the styro-slicer has adjustablepower settings, cuts at any angle you need, and the best part is, the whole system fitstogether ergonomically, for easy and clutter-free storage.

woodworking needle files, let’s start this project with a simple experiment,using a 6 volt lantern battery and a thin piece of hanger wire. if we wrap the ends of the wire around thebattery terminals, you can see it gets incredibly hot, in just an instant. if fact it’s so hot, that if we try touchingit to a small piece of styrofoam, it slices right through, like a hot knife, on butter.

that’s the basic concept of how our hotwire foam cutter is going to work, so let’s get started building the foam factory withsome 3/4” pvc tubing and a few connectors. these pieces will create the frame for ourmulti-functional wire saw, and you should be able to find all of them easily, at anyhome improvement store, in the sprinkler isle. cut two pieces of tubing 11” long, and oneother piece 12”. and the only fittings you’re going to needare two 90⺠elbows, and two slip caps. now if you’re planning to customize thecolors on your styro-slicer, go ahead and paint the elbows and the slip caps now, becauseit will save you a step later on. the next things we’ll be needing, are some#8 flat washers, and two #8 eye bolts, around 1-5/8” long.

place one of the washers on the bolt, thenscrew them both firmly into the center of the cap. i pre-drilled my hole, using a 5/32” drillbit, and it really couldn’t have worked better. now continue screwing the eye-bolt into thecap, until it’s tight against the outside washer, then do the exact same thing withthe other one. the next step is to make a hole in the centerof the12” pipe, so mark the tubing 6” from the end, and begin drilling. we only want a hole in one side though, sowhen the drill bit punches through the top, it’s time to stop. i drilled my hole 3/8” wide, but you canreally make yours any size you want, as long as you can get an electric cord to fit throughit.

and speaking of cords, we’re going to needone of those, next. all we’re really after here is the corditself, so go ahead and chop off whatever’s on the ends, then separate the two wires bycarefully pulling them apart. i split my cord into strands about 2 feetlong, which is actually a bit more than we need, but it gives us a little wiggle roomfor when we attach it in just a second. next we’ll need to expose the bare copperwire inside, so use wire strippers to remove about an inch of the plastic coating fromthe ends. then twist the strands tightly together, andbend it over, so you can twist it together at the bottom, and form a little metal loop.

carefully push the split wires through thehole in the tubing, and continue working them in, until the wires snake around the corners,and pop out the other ends. now if you can figure out how to tie a knoton the inside, the cable won’t be able to pull back out accidentally, and it’ll preventthe wires from splitting down any further. so tie it off if you can figure out how todo it. otherwise, don’t worry too much about it. all that’s left to do now, is push the individualwires through the two remaining tubes, and secure them to the end caps. add a washer to the bolt inside the cap, thenslip the wire loop over the end of the bolt and push it down to the bottom.

add one more washer and a hex nut, then usesomething like a pair of needle nose pliers to help tighten the whole assembly together. now simply push the end caps on the tubesas tightly as you can, and just like that, the frame for your wire saw is finished. you could use it just like this, but if youwant to kick it up a notch, trying using a bit of duck tape to add a splash of color. the only thing our hot wire foam cutter needsnow, is the hot wire. and for that i’ll be using a 1-1/2” extension spring, andsome stainless steel hanger wire, which you’ll find, in the hardware isle.

i got a 9 ft roll for a little under $4, whichis way more than i’ll ever need, and should last forever. measure the wire so it’s a couple incheslonger than the frame, then go ahead and snip it to size, and now here’s the cool part. if you look closely, you’ll notice the hangerwire is made of 7 smaller wires twisted together. so if we unravel them, we end up with 7, superthin, stainless steel cutting wires. and plenty more where they came from. at this point, go ahead and get the 1-1/2”extension spring ready, by connecting it to one of the eye-bolts. the easiest way to connectit is by pulling the hook open with a pair of pliers, then looping it inside the boltand letting go.

fasten one end of the steel wire, to the bottomeye-bolt by folding the wire back over itself and twisting it around a few times. now loop the other end through the bottomof the spring. but before you twist it off, pull the wire firmly, and stretch it out first. this will “spring-load” the wire withtension, which is really important for keeping it tight, when it expands and contracts rapidly. with that final step, the wire cutter’sdone. except you might have noticed, the wire’s still a bit wavy. simply take a screw, or the handle of a spoon,and slide it back and forth a few times to make the ripples disappear.

now let’s do a quick and simple test tomake sure everything got connected properly, by touching the ends of the wires, to theterminals of the lantern battery. if you did it right and your connections aresolid, the wire will heat up and slice through styrofoam, without any trouble at all. ok now that we’ve got a wire cutting blade,let’s go ahead and build the foam cutting factory i designed to go with it. the first thing you’re going to need is1/2” medium density fiberboard (mdf) cut 18” square. we’ll also need an 8 foot 2x4”, whichyou can get for about $2. i’m using a chop-saw to make quick and cleancuts, but you can use whatever tools work best for you.

but in any case, you’ll need to cut thefirst piece 18” long. then a 15” piece for the side. another 15” piece for thebottom. followed by an 11-1/2” piece for the other side. a 5” block fills the gap above that. followedby a 3-1/2” block on the bottom left. then another 3-1/2” block that’ll go inside,on the bottom right, a little later on. now that our 2x4” is cut, mark a 10” linedown the center of the mdf square, and use something like a chop saw to follow the linefrom the center marking, right out the side. you’ll see what this groove is for a littlelater. alright, it’s time to secure the blockstogether, and for that i’m using eight, 3” wood screws, and an 1/8” drill bit.

start by lining all the blocks in position,on the bottom of the board, then use the 1/8” bit to drill pilot holes in the wood. thisway, the wood won’t crack when you screw it together. the blocks go together in 3 different segments,and you should be able to figure out how to attach them, by studying how i did mine. before we go any further, let’s stop, andhack a square hole out of the 15” sidewall, to accommodate the dimmer switch we’ll beadding in just a minute. i used a 3/8” bit to drill holes in thecorners, then connected the dots with a jig saw, to cut the sides, and pop the block out. if you did it right, your hole will be onthe left side of the base, when the 18” board is facing forward.

ok let’s move onto securing the work-surfacenext. we’ll need to drill pilot holes throughthe mdf like we did for the base frame, and it’s a good idea to invest in a countersinkbit, so you can get the heads of the screws to drop below the surface. i used ten, 1-1/2” wood screws to hold theboard to the 2x4’s, and two, 3” wood screws in the upper right area, to secure the 3-1/2”reinforcing block, to the underside of the table. these are the measurements i used, and it’simportant you take time to measure and fasten yours the same way, because it’s all partof a master plan, that will come together later on. now just for fun, i thought it would be agood idea to use my flush-mount router station to quickly clean up the edges a bit, by roundingthem out.

for just a little extra effort, you can seewhat an amazing difference it makes. and all i used was a 1/2” rounding bit. if you want to see how i made this routerstation, look for how to build it, in another project video. alright, let’s make sure all the wood piecesfit together snugly, on the underside, then double-check the base support assembly didn’tget screwed on. that’s important. we still have one thing left to do with thebase support, and that’s to drill a 3/8” hole directly in the center, and 5” fromthe bottom. that’s it. at this point the workstation is finished. now just for looks, i decided to spray-paintmine black, so it would match my wire saw better, but however you color yours, is completelyup to you.

the next step in assembling our foam cuttingfactory is attaching the arm assembly, to the support base. stand the saw upright so it looks like theletter “c”, and center it in the middleof the board. now if you push a pen through the hole inthe back, and mark the tubing, you can use your 3/8” drill bit to carefully cut a matchinghole right through the tube. make sure you don’t cut the wires inside,and put something like a scrap piece of wood underneath, so you don’t scratch up yourtable when the drill finally punches through. let’s fasten the two parts together next,using a 3/8” x 3-1/2” hex bolt. two 5/16” cut washers/ a 3/8” wing nut/ and two 5/16”tank bolt washers, which you’ll find in the plumbing section. the bolt, and one washer, go on the forwardside of the tubing, while the two tank go on the back.washers

and after inserting the bolt all the way throughthe hole in the support stand, add one more washer and a wing nut, to clamp the systemtogether. the wing nut simply needs to be screwed onhand-tight, and with that final addition, you’ve just completed a stand-alone cuttingassembly, that looks awesome, and has a of really cool features. lot the cutting arm is designed to pivot on thebolt, so you can adjust the angle of the blade anyway you need it, and even 180 degrees theother way. if that’s not enough, you can release thewing-nut and slide the whole assembly out, to cut larger blocks free-handed. now to bring our styro-slicer to life we justneed a way to safely electrify it, and control

the power, so let’s finish up, with theelectrical system, next. i went to the hardware store and got a 600watt dimmer switch, that you can turn on or off just by pushing it. we’re also going to need a 12 volt powertransformer, a 10 amp fuse and another 6’ length of cord. now if you have trouble finding a transformer,or simply don’t want to shell out for one, you’ll probably be able to salvage one forfree, by hacking open an old stereo and pulling one off the power supply. that’s what idid for my first prototype, and it works just as well. the dimmer switch goes in position from theoutside, and gets secured in place, with two 1” wood screws. you’ll need a cover plate as well to makeit look nice, and when that’s screwed on, replace the knob, then flip the whole workstationover.

i decided to install my transformer abouthalfway down the side, and used two more 1” screws to secure it as tightly against thetop, as i could get it. and it helps if you position the side withthe 3 wires, facing down. the 10 amp fuse isn’t really necessary,but it’s good practice to have in place just in-case of a short, so make sure it’sactually got a fuse inside, then go ahead and connect everything together, using thesmall wire nuts that came with the dimmer switch. now to save time, i went ahead and just wiredeverything together. and after you do the same, it should look something like this. you can see the main power cord comes in fromthe outlet and connects to the 10 amp fuse

first, which then connects to the black wireon the dimmer switch next. the red wire coming out of the dimmer switchconnects to the black cord on the primary side of the transformer, and the other blackcord connects to the wire running back to the outlet. now on the secondary side of the transformer,you might have noticed two yellow wires and one black one. the two yellow wires supply 12 volts, andthe black wire is center-tapped for half power. this means that connecting them to a 3 positionswitch will give us the option to cycle the system between 0 volts, 6 volts and 12 volts,on demand. now it doesn’t really matter which yellowwire you connect to the switch, as long as it’s soldered to one side, with the blackwire soldered to the other.

the remaining yellow wire needs to be connectedto the cord running to the hot wire assembly. and the return wire, connects back to themiddle, of the 3 position switch. it sounds complicated, but it’s really notthat bad once you get into it. now the two power cords are designed to feedout the back, so they don’t get in the way. one cord is for the supply power, that getsplugged into any regular power outlet. and the other cord, runs the regulated power tothe cutter assembly. at this point, the styro-slicer is done, andready to use as soon as you are. simply push the cutting arm into place, withthe wire in the center of the work surface, then flip the red switch to the 6 volt setting,which i call “normal power”.

push the dimmer switch on, then gently crankup the power, and you’re in business. if everything’s working the way it should,your wire will instantly heat up, and you can start slicing through styrofoam rightaway. making some of the smoothest, and cleanest cuts, you can imagine. for one final touch, i added a couple 1”screws to the inside of the base, so we can store the rest of the hanger wire, then secureda latch on the upper side of the support stand, so the whole system locks together, for quickand easy storage. by the way, there’s also a backup batterycable in there, that will connect the system to solar, or battery power, which makes thewhole system portable, and off the grid. well now you know how to rise up, and becomea master styrofoam maker, by building yourself

a homemade styro-slicer. that gives you precision control for cuttingcustom props like a mini master sword. or slicing out something more intricate, likea squadron of 3d fighter jets. look for how to make these in another video. well that’s it for now. if you liked thisproject, perhaps you’ll like some of my others. check them out at www.thekingofrandom.com