I did a lot of research on this. Components to make, the type of carbon, how long it lasts, blah.

It is cheaper, the first time around to buy a commercial carbon filter. The cost is the carbon.

Now, carbon can be reactivated by reheating to over 400 for several hours. I hope to be able (and it looks like I can) when this one needs changing to disassemble and recycle the carbon and put it back together.

For now, it works, cuts down on noise too