Its a combo and parts and ideas I pulled from here and my garage.
Parts used:
Pool cue
Pvc check valve for the hilt
The grips are spaced out O rings with elecrical heat shrink tubing shrunk over them
a flexible funnel tip for the rasp
Tip from a liquid nails bottle is the tip
I like the idea of the heat shrink take as well...the only issue I can foresee is a rip or tare being difficult to repair. Though...if it's large enough I bet it'll fit over the tip and all will be good. Instead of a ridged handle I went with a solid piece of PVC which I sprayed with liquid rubber/plastic (Plasti-dip). I had an issue where they got ripped and I had to peal the whole thing away and re-spray it. Not a big deal but if I had it to do over again I'd have used black PVC instead of white so if it ripped I didn't have a brilliant white streak showing through.
Yeah I was concerned too but since I used big enough tubing (1.5 inch!) it shrunk down pretty tight. Luckily if it tears I can slide another one down and heat it up. I put two coats of flat black on them as well so hopefully that gives it some protection.