Home Depot? Hunh. You sure that's not a brand name? either way, I wouldn't worry much about it. different part of plants often have very different properties. You'd be surprised at the differences between raspberries, raspberry leaves and their roots.

If it's already together, just keep an eye on it. you should be fine. Just keep the first few trials away from audiences until it's good an broken-in. Keep an eye on the tape and just remember that dropping the tool is an option if things go awry.

In the future, test your tape on any ol stick with cloth wrapped around the tape. Light it up with fuel and let it burn through.

it has to do with fire on the inside. When you move the pipe in a way that there is an airflow through the pipe, it basically becomes a very rudimentary pulsejet. You'll hear it with firestaff sometimes, it's this weird fwish or fwunk sound. I've (ONCE damnit) been able to through-light a staff. (Have one end on fire, swing it in such a way that fire goes down the center and ignites the other end. Looks damn magical). I don't know if a sword would do this, because you'd NEVER do any motions where you are leading the open-end towards air (creating a flow through the tube), unless you've got a lot of stuff over your hands. Eitherway, it's probably a moot point, because putting a dowel in the bottom and then pouring molten lead (fishing weights) into holes drilled in said dowel would probably be the eaisest and most accurate way to counter-weight.

Also, fyi: the eaisest way to counterweight is to put around 5/8th to 7/8th the amount of water you would put fuel on the wick and balance it for that. you ALWAYS want to weight a sword for it being wet, and not being dry (unlike what I did with my first set). water weighs something like 8lb/gal, kero is around 6.5/gal, white gas is slightly less than that.

And why it gets the tube hot is pretty obvious when you realize that there is fire going through the middle of it.