To be very honest with you I tried many ways of what they are talking about, with air water pure water chemicals, my impression is that no one following Ronnieis going to get anywhere because first of all he do not appear to be interested in making anyone's else cells work, he is only trying to make everyone to make the hard work for him. I highly doubt he ever had a working cell but this is my mere opinion based on his story tells... people expect that some info will unlock the knowledge without a scientific background, sorry disappoint you but I assume I would not be capable myself of what I'm today without the physics university... so hope for the best but don't waste time waiting others... my 11 cell in Delrin is ready since January of 2014 if I remember well and since than nothing prove that something is happening
Air core is great for resonance is the best Q factor possible for a coil but in case you want to develop magnetic field a piece of iron would amplify it 200 times for the same current and wire length..