seaman:
Hello Mr Stone. I visited your web page and i'm amazed by you power head idea. Down here in Baja we have no access to power heads. But i really want to dive with one for safety reasons... Cold you please tell me how???
To Stone. I'd love to perforate fish with you send private email. MK
To seaman, I used polyethylene pipe same diameter as an M16 round that also perfectly fit a JBL thin spinner two barb tip. The steel is pressed out to a wider Bulb at the barbs and will provide a friction seal to the tube. This tube allows very little "slop" such that the tip of a tricut or rock point will contact the primer.
first, the bullet is inserted into the plastic tube with the help of a heat gun (use on the plastic tube to soften the tube, NOT the bullet). once cooled, there is no getting the bullet out without shooting.
the spear end of the tube is cut to custom length once the bullet is firmly within the tube.Make the spear point end just long enough to go onto the Bulb area so the point will just contact the primer and penetrate about 1/8 inch. I then cut away the excess plastic that would contact the barbs. A band saw works nicely for these cuts. 2 wings willl be left to squeeze onto the bulbous area of the point.
Outside the thinner plastic tube, I used a length of 1/2 pvc pipe over the bullet area centered in the middle with electrician's tape around the thin tube to provide a fricrtion fit to the larger tube. then, toothpick segments at the ends center the outer tube on the bullet tube. Hot melt glue over the cut off toothpick ends completes the power head.
before putting the bullet in the tube, seal the bullet to casing ,and seal the primer against seawater with a couple of coats of nail polish.
Also, i did a web search for limited use powerheads and someone makes an aluminum version that sells retail for $50-$60, can be found online for about $37 , can't remember where. Happy hunting and safe diving.