19-10-2016, 09:32 PM
Yes, probably steel. It never ocurred to me that it might not work. It is probably not magnetic anyway! The first one I made, I had the valve (an EF39) down the centre of the coil to save space, and that worked as well! 
This one is a neater version. I began by looking for a large spring rather than trying to wind a neat coil from copper. I had almost given up my search when I came across the slinky spring on Ebay.
Bob
This one is a neater version. I began by looking for a large spring rather than trying to wind a neat coil from copper. I had almost given up my search when I came across the slinky spring on Ebay. Bob
