the reply button here wasent working hope it is now i haven't made any more hdr units the last one i have ill save for a latter date when i can find a real vortex to test it fully on , my electromagnet design is much better you can run it for more than an hour and it never gets hot i used pvc i recycled from 90 mil diameter storm water pipes for the ends but when you heat pvc to flatten it out and cut it it get temperd and harder and can break easy i sent one to eastern states here it got Brocken in transit by Australian post and i got fed up chasing the $90 for the damage of it by them i gave up as they made it hard to recoup the money lost in sending it so it wont survive the post and the copper wire i used from a 40 kilo spool has went up in price from the $176 i paid for mine into the hundred's of dollars when i last phone the place i got it from to check the price so i cant afford any more not from them rip off merchants . our electronics stores are tight asses as they dont sell enough coper wire on there small spools to make a decent electromagnet . you can only get small amounts at any electronics store here .