K6JCA: July 2014

Monday, July 28, 2014

Bass Guitar Body Painting Jig

When I painted a bass guitar body last year, this was the technique I used (described here: http://k6jca.blogspot.com/2013/09/building-bass-guitar-kit-part-2.html):

Not a great way to do it. The bass body was awkward to hold, and the paint layers around the bottom edge were too thin because of the difficult painting angle.

So, when I recently decided to paint another bass body, I thought it best to make some sort of jig to hold the body during painting.

Here's what I came up with, using materials purchased at the local hardware store:

During the painting process (e.g. primer coat, base color coat, and clear coats), the body is mounted to an assembly that is never removed. This assembly consists of a neck stick (short length of hardwood, attached to the neck via the body's neck holes). And as part of this assembly this stick is attached, in turn, to an 18" length of 1/2" pipe, using a pipe flange and some couplings. This pipe allows me to rotate the body in the jig and also lets me hang the body vertically while a paint coat cures. More on this later.

Here I'm holding the "neck stick assembly":

Here's the basic jig with the bass body and its "neck stick assembly" removed.

To build this jig I used the following materials:

The base mounting wood is a piece of Melamine Shelving (23 3/4" x 48" x 3/4"). But any scrap wood of the appropriate size should be fine.

Two 1/2" Floor Flanges are attached to this base.

The vertical pipes are each 1/2" x 36" threaded pipes.

These each go into one end of a 1/2" Tee.

The horizontal member between the two 1/2" Tees is a 1/2" x 12" threaded pipe.

And into the top of each Tee is screwed a 1/2" x 1" length of threaded pipe.

All of these pipes are screwed down tightly!

I've screwed a 1" x 1" x 1/2" PVC reduction Tee onto the tops of each of the two 1/2" x 1" threaded pipes.

Here's a closeup of the left-hand one. Short lengths of 1" Schedule 40 PVC pipe are glued into each end of the Tee.

And here's the other PVC Tee. I hacksawed slits into the PVC piece glued into the left-side of the Tee, and I placed a hose clamp over the slits. This hose clamp, when tightened, securely holds the body at any rotational angle I desire.

Here are the two floor flanges, with the vertical pipes screwed into them. I tightly attached the pipes to these flanges (and built the rest of the jig) before I mounted the flanges onto the bottom piece of wood.

To keep the jig from rocking on the nuts holding the flange screws to the bottom-side of the wood mount, I attached lengths of inexpensive 11/16" x 2 3/8 furring strips along the bottom sides of the wood mount.

Here's the assembly that attaches to the base body:

I've attached a 1/2" floor flange to the "neck stick"

A short length of 1/2" threaded pipe attaches the floor flange to a 1/2" Tee.

Into the Tee is threaded an 18" of 1/2" threaded pipe.

(Tighten down all these joints!)

I also screwed in a 1/2" PVC threaded coupling into the 1/2" Tee, and into this coupling I glued a scrap piece of 1/2" PVC pipe. This the handle I use to rotate the bass body.

By the way, if the hose clamp is really tightened down hard, the 18" pipe won't move while you rotate the body. NOT GOOD -- this means that pipe is unscrewing from the Tee attaching it to the bass' "neck stick" when you are rotating it. Worst case: the body will unexpectedly fall to the ground.

Oops!

So I added a little note to remind myself not to over-tighten the hose clamp.

After the body is painted, I hang it vertically to dry. To do this, I made a hook assembly that I can screw onto the end of the 18" piece of 1/2" pipe that is part of the "neck stick assembly".

Here's what the hook assembly looks like:

I drilled a hole in a 3/4" threaded PVC cap and then attached a hook. A 3/4" x 1/2" PVC bushing is then threaded into the cap.

There's a nut on outside of the cap (see picture above) and a nut on the inside (and you can also see internal threads of the PVC bushing).

Here's the hook assembly screwed onto the end of the 18" pipe:

And here's the body, hanging to dry after I had applied its sealer coat.

Here are some pictures of the jig in action, in my home-made paint booth (using inexpensive 9' x 12' paper drop "cloths" above and below):

Primed body, awaiting color:

Color coat being applied (Volkswagen "Mellow Yellow"):

Another shot of the paint booth. The inexpensive paper awning is thumb-tacked to a wooden arbor and the paper, where the thumb-tacks penetrate, is reinforced with short pieces of duct tape, so that the paper doesn't rip.