Friday, 9 August 2013

12 String 335 - Polishing and Shielding

Great progress today - i *finally* got the polishing finished on my 335 12 string, and I also managed to shield the pickup cavities ready to receive their glorious GFS Surf 90s!

I started the polishing process after having wet-sanding with 1500 grit paper and applying a final coat of tru-oil thinned to 50% with turps. Polishing proceeded in 4 stages, with the first stage being a wet-sand with 2000 grit wet-and-dry using boiled linseed oil as the lubricant. I wet-sanded until the surface felt smooth and sanding marks covered the majority of the surface. The surface wasn't as dull as it probably should have been, but this wasn't unexpected given that I didn't leave all my wet-sanding until the last coat of Tru-oil was applied.

After the 2000 grade wet-sand, I then applied sucessive Stewmac polishing compounds - starting with Medium, then moving to Fine and Swirl Remover to remove the sanding scratches and bring out the shine.


I applied each successive compound using my electric drill and some small (3cm) foam polishing pads I purchased from Aussie site polish-up.com.au.  The shine that resulted was surprising, with the Tru-oil displaying a satisfyingly reflective gloss finish, and a deep translucency that unfortunately shows up every little mistake I made when applying each layer of oil. The flame maple has really popped, and the 3d or "chatoyance" effect as you move around the guitar is fantastic. In short, I'm very happy with how the finish has turned out!


With polishing complete, it was time to turn my attention to preparing the guitar for wiring - notably, shielding the pickup cavities with some dual-sided conductive copper foil. This stuff is great - it comes with stickum on the back and simply lays down like tape (if a little harder to handle). Each strip lays over the strip next to it and the whole thing forms a wonderfully conductive sheet (resistance is effectively negligable).


"chatoyance"
You can even solder onto it! I was able to easily solder wire from the neck cavity to the bridge cavity without any trouble at all. When the bridge is finally installed, i will be able to solder the bridge ground wire to the shielding around the bridge pickup,  and then run another wire from the shielding out to the wiring harness. Exciting times ahead!