Bluebird K7
Hot wire foam cutter:
I started off by watching just about every video on YouTube on the subject.
I then bought a few meters of 0.25mm NiChrome wire.
At first I thought I'd just need a vertical bench top cutter.
An unwanted shelf was liberated from a kitchen unit to use as the base, a couple of 2x1's were screwed underneath to give clearance for the wire connection. A piece of MDF was used for the upper arm.
To give some adjustment underneath a block of wood with a screw in one end for the wire to wrap around was screwed to the base in just one position so the block could pivot.
I drilled a clearance hole in the end of the upper arm for a long bolt & put a small slot in the end of the bolt to wrap the wire around, a washer and spring were used to give the wire some tension. When the wire heats up it expands so you need something to maintain the tension.
Wrap the NiChrome wire on the screw underneath, put it through a hole cunningly placed in line in the base & up to the slot in the bolt in the upper arm, compressing the spring at the same time.
Now that's all sorted get 2 pieces of normal wire, attach one to the screw underneath & one to the bolt on top.
This is the bit where I found conflicting information on YouTube, people used all sorts of different things to power their cutters, batteries, pc power supplies & resistors, model railway power supplies, laptop chargers etc etc, everyone recommend different voltages & amperages. Luckily my Lipo charger can be sued as a power supply so I started messing with volt/amp settings, I didn't want the wire to glow red as that's too hot, I ended up using 10 volts & 2 amps, it works a treat.
Unfortunately this cutter does have its limitations, throat depth etc.
I decided I needed a hand held cutter, going off what I'd learned from the bench cutter this was a doddle.
2 pieces of 7mm steel bar 300mm long, 2mm hole in each end.
1 piece of 30mm square pine for the handle, 8mm hole through each end.
Smack bars through holes in handle, get 2 pieces of normal wire, attach one to each hole at handle end, I just twisted them on & taped everything over.
Now here's the trick with the other end, when you attach the NiChrome wire make sure you squeeze the bars together a little to give the tension, attach the other ends of the wires to the power supply & away you go.
Like any tool I guess you get better with practice, lol
Cheers
Wayne
