The goal of this ible is to show you how to make a simple and inexpensive foam cutting blade. I've already posted how to make hot wire cutters, and there are hot knives and scoring method, but I have found what is probably the easiest and cheapest way to cut long perfect piece for uses like home insulation.
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Step 1: Material
What you will need to make your own foam cutting blade is...
- A grinder with the metal cutting disc
- Some scrap to hold the circular saw blade in place (I used a chunk of 2x4, a screw with a washer larger than the arbor, and a clamp)
- Safety gear (ear muffs; I use these awesome radio/headphone ones, face mask, goggles)
- And finally the circular saw blade you will use as a blank. To make your life easier, you want something cheap with very little kirf, short teeth, and no carbide. I made a 5 inch, and a 10 inch, the same things apply to 6 1/2 and 7 1/4 blades.
Step 2: How It Works
The end goal is to make a knife style edge on the blade so that it sices, but without the teeth it can't just rip chunks out. That will get the cut started. For the slicing, we rely on the heat from the friction, this is why we don't just go really slow with a toothed blade. Teeth on blades have a kirf and gullet to help clear chips and let air cool the blade. With no teeth, we will be heating up the blade in the foam.
The video above demos my two kinds of foam cutters, each being used for their strength.
Step 3: Grind the Teeth Away
Find a spot to secure the blade in place, and start grinding at a 45 degree angle. Flip it, and repeat. At this point you should now be able to remove the teeth.
Step 4: Smooth and Sharpen
Grind dead on to the bumps left of what the teeth were. After, give it another pass at 45 degrees to give it back its sharp-ish edge.
Step 5: Cut Foam
That's it, you can now do perfect, long, mess free cuts in foam blocks. I also made a 10 inch version, which you can see in action in the video above.