Shielding PI coil...conductive paint on coil housing halves?

[bchampig]

Hello,

I am in the process of making a 10" mono coil for a Hammerhead PI machine using a Hays coil housing. I bought some EZ-Slide graphite paint for shielding. My coil is wrapped with two layers of poly spiral wrap. My original intent was to use some micropore tape wrapped tightly around the spiral wrap, and then paint it with the EZ-Slide, but I am wondering if I should just paint the inside of both coil housing pieces and call it a day?

Does anyone have a recommendation?

Thanks in advance,
Brian

[IBGold]

Hi the further the shield is from the coil bundle the lower the coil to shield capacitance will be and the faster the coil you could shield the housings but it is not optimum I make a Styrofoam former in two halves route out the center to fit the coil bundle glue the forms together and end up with a 25 to 26 mm round form the shape of and encapsulating the coil bundle I then spiral wrap a .2 mm tined wire at around 50 to 75 mm pitch one end of which becomes your shield connection wire and then I paint the outside of the form with the shield paint leaving a 1/8" break so it is not seen as a shorted turn I have found this is superior to painting the housing but I do try for ultimate performance in my coils hope this helps you.
Regards,Ian.

[bchampig]

Thanks for the advice Ian, I appreciate it. My coil is already a pretty tight fit inside my coil housing with the two layers of spiral wrap spacing material, so with my particular housing, there is no way to fit styrafoam around the coil bundle. If I paint the insides of the housing, I hope that the spiral wrap will create enough of a gap to keep the capacitance down.

Thanks again,
Brian

[Ism]

Since you already have two layers of spiral wrap and a tight fit, you should go with your original idea. That way you can test the coil before assembling it. Spraying the inside of the housing doesn't allow for much error.