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.
Giveaway: follow my instructables and YouTube channels and post an "I've made it" picture to get the free pro membership voucher I got when this instructables was featured.
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
Step 4: Smooth and Sharpen
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.