i have wanted to build a hot wire foam cutter for the longest time so i can start cutting airfoiled
wings for my foamies. I had been searching around online for a good set of plans, and i finally
found a site that had very good instructions on how to build one of these crazy contraptions;-)
the website is: www.utahflyers.org. here is a link to the cutter page:
http://www.utahflyers.org/index.php?...d=37&Itemid=33
on with the build! i'll start with the power supply:
So i went to the local Home Depot yesterday and started gathering materials for the build.
I started with the DIY power supply wich consists of a 3-wire extention cord, a rotary dimmer
switch,(to adjust current to the cutting wire), a GFI outlet, a standard outlet(wired in to see
when the unit is switched on), a 3 port outlet box,(to hold everything), a nightlight(plugs in to
the standard outlet to know when unit is turned on), and the most important part, a 24volt 3-5
amp transformer to power the cutting wire.
Im sure there are easier ways to build a power supply, but im not an electrician, so i just
went off the plans shown on the website, because I dont feel like blowing myself up trying to
build something on my own:-)
the first pic is the diagram that i used to build the power supply.
the other pics are the unit mostly finished...I still have to get an outlet cover to make it pretty
and i'm going to mount the unit on wood and try to enclose everything.
the transformer will mount next to the outlet box, and attach to the loose wires coming out.
the cutting wire leads will attach to the transformer, and run down to the cutting bow, and will
attach to the cutting wire with aligator clips on either side of the wire.
I will post pics and describe everything that i do until the build is finished.

Cool

it doesnt look like much yet, but when its finished, i'll be able to mass-produce any airfoiled wing that i make a template
for:-)

Jared - one of the tricks I have learned is when you make your templates, number the edges from 1 thru ten from the leading edge to the trailing edge. Then get a helper to help you do the cutting. The guy on the root end of the wing does the calling "1...1 1/2... 2... 2 1/2 ...3...", the guy on the wing tip keeps his end of the wire on the same number.

Also decide when you make the templates how the wire will enter and exit. I like to make the templates with an extension on the leading edge and trailing edge. I'll have to take a picture to explain this.

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Jared I like the Idea. My nice one burn up I told Dan.
Smoked it...

thanks for the tip dave. The first setup i am building is a guillitine cutter to chop big blocks
into usable pieces. this one is simple.... the bow will be suspended from a bungee cord from the
ceiling. the guillitine table has two building squares (2 on each side of the table) mounted on the sides of the table and will have a 1/2 inch gap between them. The wire will drop between the gap down onto the foam.
after the cut, the wire drops below the table into a slot cut in the wood so I can easily remove
the foam from the table without the wire getting in the way.
the second setup is basicly for cutting small solid core airfoiled wings... I will have one end of the bow attached to a fixed point on one end of the table, and the other end of the bow will be floating. this way i can use a one-piece airfoiled jig anchored to the oposite end of the table from
the anchored cutting wire.
basicly i'll have a block of foam weighed down to keep it from moving, and i will pull the wire
through the jig, trace the airfoil, and exit at the same gap in the jig that the wire entered.
sounds more complicated than it really is

This rig was designed mostly for small wings. down the road i may build something bigger
to cut wing cores for larger planes, but i just want to cut small airfoiled wings for foamies
right now.

Originally Posted by HuckinChikn

i have wanted to build a hot wire foam cutter for the longest time so i can start cutting airfoiled
wings for my foamies. I had been searching around online for a good set of plans, and i finally
found a site that had very good instructions on how to build one of these crazy contraptions;-)
the website is: www.utahflyers.org. here is a link to the cutter page:
http://www.utahflyers.org/index.php?...d=37&Itemid=33
on with the build! i'll start with the power supply:
So i went to the local Home Depot yesterday and started gathering materials for the build.
I started with the DIY power supply wich consists of a 3-wire extention cord, a rotary dimmer
switch,(to adjust current to the cutting wire), a GFI outlet, a standard outlet(wired in to see
when the unit is switched on), a 3 port outlet box,(to hold everything), a nightlight(plugs in to
the standard outlet to know when unit is turned on), and the most important part, a 24volt 3-5
amp transformer to power the cutting wire.
Im sure there are easier ways to build a power supply, but im not an electrician, so i just
went off the plans shown on the website, because I dont feel like blowing myself up trying to
build something on my own:-)
the first pic is the diagram that i used to build the power supply.
the other pics are the unit mostly finished...I still have to get an outlet cover to make it pretty
and i'm going to mount the unit on wood and try to enclose everything.
the transformer will mount next to the outlet box, and attach to the loose wires coming out.
the cutting wire leads will attach to the transformer, and run down to the cutting bow, and will
attach to the cutting wire with aligator clips on either side of the wire.
I will post pics and describe everything that i do until the build is finished.

Funny you posted this today Jared! A buddy of mine and I just built a hotwire setup this weekend to cut wings for our Q500 racers. It cost us about 50 bucks and works great! We used a 1.25amp (stable) AC to DC 24 volt power supply and used stainless .011 fishing leader for our cutting wire. We cut out about 8 wings last night and only after a few adjustments, it was working flawlessly. We used a weighted cantilever system to pull the bow across our cutting table instead of using man-power. This allows us to play around and adjust the weight to where we need it, and for that way we have the exact same setting each time for consistant cuts each and every time. I will have to put pics when I get home tonight. Ours is built to cut panels up to 48" wide and with chords of up to 12".

So the total cost sofar?

Jared.
You know I'm so old I Fart Balsa Dust.... I'd buy the foam chucks right down the street from Ryan's work on Dorsett. Buy what ever pound you want. All types and sizes. I Just told Dan I have screwed 2 each 2X4's to table. I tied the wire to one end of board and put the spring to other end of wire and hooked that other 2X4. put my ply guides to each end of small chuck. Heated the wire with a butane torch and run the wire through for cut out. Cheap. Then they came out with the Bow selling in our AMA Mags. I took my Bow Jared and cut Giant scale stinger wing cores back in the days. We start talking back and forth, because Jagger's mean wire to cold or the other guy pulling with you to slow.
How times keep coming back just better Technology..

Rich - Does Ryan work for "Foam Products" at 739-8100? I have bought foam from them before but they did not seem to really like to sell over the counter.

pics of our setup we built this weekend...

Originally Posted by Xpress..

So the total cost sofar?

Our total cost was about 50 bucks, w/o the power supply which we already had.

Hey Jared, I finally got my Hot wire cutter done and just about ready to go. I built the power supply pretty much like the one you suggested... (I still have my tattoo power supply but I use it for my small bow cutter and table cutter).
I don't have my power transformer yet so I just use a 6S 3000mah lipo for now and it works great.

I've cut a few more wings and they are looking a lot smoother with the new Rig.

I'll try and finish up a plane and bring it to the gym tomorrow.

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