one of the more difficult pickup installs is when you need to enlarge a pickup cavity on a contoured top instrument - the exact scenario encountered with this mod ...
after checking to verify that the bass finish is not lacquer (blue tape turns lacquer gummy), the first step is to determine which direction(s) the existing pickup cavity needs to be enlarged in. looking at this gutted Artcore, it became obvious that I needed to install the Darkstar towards the neck due to the top contour.
here you can see the routing template set into place to mark the cavity outline in preparation for routing
once marked, I took the bass to a drill press and utilized a Forstner bit to remove most of the excess body wood. I like to leave about 1/32" of excess on the sides and 1/8" excess on the bottom
because this was a contoured top, I left a little more on the sides just in case. I next shim the routing template into place so that the top of the template is planar to the neck face. this template needs to be really, really secure - difficult to do with all of the contour which limits contact points
once the template is secured, it's time to route away
leaving a nice cavity for the new pickup
it was interesting to note that an Artcore has an internal wooden honeycomb core
next it's time for a coat of shielding paint followed by a 24 hour cure cycle. repeat this step two additional times
once the shileding paint has dried, it's time to pre-fit the pickup into its new home. here I have simply taped it into place so I can determine whether I want the pole pieces towards the neck or towards the bridge. I routed the cavity so that the owner can flip the pickup 180 degrees to suit his sonic preferences
being a hollowbody, it's pretty much impossible to shiled the wiring ... this makes it very important to twist/braid the wires to help reduce them acting like an antenna
Viola! the completed install. you can also see the black plastic mounting plate under the pickup - this allowed me to account for the contoured top and provide a flat base to mount the pickup
a similar workflow was used to upgrade this Epiphone Jack Cassady bass
before:
after:
the mounting plate for this one was made from some Cocobolo stock I have left over from a set of fretboards I made earlier in the year
all the best,
R