by liahgeron » Thu Aug 22, 2013 3:14 pm
Cathy has the right of it. The more you add to the blade, the more mass gets swung. This increases hitting power and requires more wrist strength to control.
You can use lighter things like open cell foam strips or the insulation foam you edge doors with to reduce the weight you're adding to get the form(plus they are MUCH softer). I recently made a rather broad bladed "feather" that some might have seen at Cottington. Despite it's size (about 4-5 inches broad) it was still only about half again the weight of a Ben Becker weapon (260g*1.5 < 370g) thanks to being mostly open cell foam. My katana have heavier handles to balance them properly with the extra foam on the edge, but still run in the 270-350g range. The better balance makes them strike less heavily due to the better control you get. It's a bit counter intuitive, but you need less force to get it to move even though it weighs more. The harder the weapon is to move, the more strength you will unconsciously put into it and the less happy your target will be. This is not to say the balance will solve all your problems though, the more weight you add to balance, the more angular momentum you add when striking from the wrist. So you need to watch that as well and strike a balance. I usually do the pommel of my weapons last so I can get someone to hit me with both the light and more balanced versions and make my decision then.
On tape, Ripstop repair tape is much more expensive than duct, but I honestly prefer it to make all my blades. It is significantly lighter and tips made of it don't shred over time as happens to ones made of duct tape. It is also forgiving of adjustments made after the fact as doesn't stick permanently. It does unfortunately have a tendency to "bubble" though after it gets wet, but sticking it near an AC unit will usually dry out the water and let it stick back down properly. I will also second only using 1 layer of duct tape where possible. Due to it's thickness and stickiness, it actually can tighten the foam underneath and make it a significantly harder striking surface.