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.

That's it!

Update:

There's an interesting discussion on the Talkbass forum  regarding this jig and others (there are some very clever designs).  You can read it here:

    http://www.talkbass.com/threads/jig-for-painting-a-bass-body.1092902/


Links to Bass posts of mine...

Sonic Blue Bass (part 1 of a 3 part series)

Mellow Yellow Bass

Short-scale Telecaster Bass

Bass Guitar Painting Jig

Repairing a G&L Butterscotch Blonde Paint Chip

G&L ASAT Bass Strap-button Extender

Modifying a 75 ohm HP 85046B S-Parameter Test Set to be 50 ohms

A while ago I purchased an HP 8753A Network Analyzer to replace the HP 8505A Analyzer that I had been using in my home lab.  But I'd been delaying putting it into that rack where the 8505A has been, because I first wanted to get a 50-ohm S-Parameter test set for it.

The thing is, S-Parameter Test Sets for the 8753A, such as the 85046A, are expensive, and I'm cheap.

Recently I visited a friend, Dick (W1QG), who also has an 8753 Network Analyzer, and he showed me how he had modified a less-expensive 8503A (the S-Parameter test set for the 8505A analyzer) to work with the 8753.

He had added a latch and a one-shot to the 8503A (to generate the 200 msec Sweep-Delay signal for the 8753), and the circuit looked straight-forward and easy to implement. 

Dick mentioned, too, that although the 8503A is only spec'd to 1.3 GHz, he could operate his up to around 2 GHz with minor correction factors.

Sounded like a good approach.  And I had an 8503A.

The next day, though, happened to be the De Anza swapmeet in Cupertino.  And while walking its aisles I came across an 85046B S-Parameter Test Set.

Although directly compatible with my 8753A Network Analyzer (unlike my 8503A), this Test Set had a number of issues, the first being that it was 75, not 50, ohms.  Also, the seller told me that he'd removed its "Transfer Switch" (that's the coaxial relay inside it), and overall operating condition was unknown.

On the other hand...it was cheap!  And an idea hit me: rather than build the interface circuit that Dick had designed into my 8503A, would an easier approach be to somehow combine the 85046B's interface with my 8503A?

I had no idea if I could or couldn't, but the price was right, and I thought it would be fun to investigate.  So home it came with me.

Replacing the Missing Parts...

Fortunately, the Operating and Service Manual for the 85046A/B is available on the internet  ( Click here for manual).  Looking it over, it became clear that, with the exception of the 85046B's Bridge and Bridge/Splitter modules, everything else in the 75 ohm box was actually 50 ohms

I also noted that the 85043A/B had a 0-40 dB step attenuator (10 dB steps) that the 8503A did not have.

Comparing photographs in the 85046A/B and 8503A service modules, the Bridge and Bridge/Splitter modules looked very similar.

Hmmm...rather than modifying the 8503A to work with the 8753A, if I instead modified the 85046B to be 50 ohms, I'd already have (with no work on my part):

1. A fully functional interface designed specifically for the 8753A.
2. The 40 dB step attenuator.

And of course, it wouldn't hurt that the four N connectors for attaching the 85046 to the 8753 would properly line up with the 8753's four N connectors (unlike the 8503A).

It looked like all I needed to do would be to transfer the 50 ohm Bridge and Bridge/Splitter from the the 8503A to the 85046B!

Before I progressed further, though, I needed to replace the missing parts.  For the Transfer Switch (coaxial relay), I could have taken the one out of my 8503A, but that one was only rated to 1.5GHz (HP p/n: 08503-60035), while the proper one for the 85046A/B is rated to 18 GHz (HP 08503-60051).

Also, I discovered that one of the internal metal coax interconnect cables was missing. Fortunately, using the manual I found its part number (HP 85046-20009).  I Googled it and quickly found a company who could sell me both the cable and the Transfer Switch.

While they were in transit I looked over the 85046B manual further and discovered that there were two flavors of Logic boards; one board is designed to for use with a mechanical transfer switch (like the one I'd ordered), and the other is designed for use with a solid-state transfer switch.

The main difference between the two boards is the difference in the timing of the "Sweep-Delay" pulse generated for for the 8753 Network Analyzer whenever the Transfer Switch or Step Attenuator is changed (per this illustration):

(Click on Image to Enlarge)

Well, the board in my 85046B had a part number of 85046-60016.  Unfortunately, this was the board designed to work with  the solid-state transfer switch.  But I had the mechanical transfer switch, and so I really should be using the other logic board (HP 85046-60051) to create the proper 200 msec. Sweep-Delay pulse for the 8753A:

Fortunately, the PCB is common to both Logic boards, and there's only a slight difference in component values. Here's a summary of those differences:

        Solid-State Switch     Mechanical Switch
          (85046-60016)          (85046-60051)
   R7     39 ohms                  56 ohms (2 watts)
   C2     4,700uF, 35V         10,000uF, 35v 
   R25   0 ohms                    unstuffed
   R5     0 ohms                    unstuffed

So changing a -60016 board into a -60051 board couldn't be easier.  I just lifted one end on both R5 and R25 and called it a day.

(I lifted one end of each resistor, rather than removing the resistors entirely, so that I could easily convert the board back to its original state, should I ever need to.  And I didn't change R7 and C2 because they did not seem critical to me.  Given that the transfer switch's coil resistance is 200 ohms, I couldn't see a good reason to change R7 to 56 ohms.  And, although I would have replaced the 4,700uF cap with a 10,000uF cap if I'd had one, there wasn't one in my junk box. So I left it unchanged.)

Here's the new Transfer (Coaxial) Switch

Replacing the Bridge and Bridge/Splitter...

The next step was to remove the 75 ohm Bridge and Bridge/Splitter from the 85046B and replace them with the 50 ohm Bridge and Bridge/Splitter from my 8503A.  Here are the steps.  Apply to both the 85046B and the 8503A:

1. Disconnect the SMA connectors attaching the RF plumbing to these two modules.
2. Remove the four screws (and, where used, the four white shoulder-washers) holding each module to the chassis.
3. Unplug from the PCB the single wire that goes to each box. 

Below is pictured one of the 75 ohm modules and one of the 50 ohm modules.  Physically they are identical (with the exception of the Test Port connectors on the right side, of course).

75 ohm unit from 85046B is on the top.

50 ohm unit from 8503A is on the bottom. 

I also moved the Blue and Gray wires from the 75 ohm boxes to the 50 ohms boxes (the wires attached to the 8503A modules are not long enough to attach to the Logic board in the 85046B).

And then I installed the 50 ohm Bridge and Bridge/Splitter into the 85046B, making sure that the modules were the appropriate side up so that the SMA connectors all aligned properly.

To summarize, if you have an 8503A gathering dust, using it to convert a 75 ohm 85046B to 50 ohms is very simple.  Here is all that I did:

1. I replaced the 85046B's 75 ohm Bridge/Splitter (p/n 5086-7448) with the 50 ohm Bridge/Splitter (p/n 5086-7240) from my 8503A.  
2. And I replaced the shorter yellow wire on the 5086-7240 with the longer Blue wire from the 5086-7448.
3. I replaced the 85046B's 75 ohm Bridge (p/n 5086-7449) with the 50 ohm Bridge (p/n 5086-7229) from my 8503A.  
4. And I replaced the shorter light-brown wire on the 5086-7229 with the longer Gray wire from the 5086-7449.

Here are the 50 ohm Bridge and Bridge/Splitter installed in the 85046B

A work in progress...

 

My initial testing (network analyzer not calibrated, so no correction factors have yet been applied)...

S11, open circuit:

S11, 50 ohm load

It seems to work!  I don't expect to get the full range of operation that an 85046A would give (to 3 GHz), because the 8503A modules are only spec'd to 1.3 GHz.  But, for me, this was a quick way to get an inexpensive, yet acceptable, S-Parameter Test Unit for my 8753A analyzer.

Addendum, 1 July 2015:

In the comments section below, David Kirkby,G8WRB mentioned a problem he had with the lid of the 8505A bridge missing the required four tapped mounting holes.  He sent along the following picture to illustrate the issue:

The unit on the left is the 75 ohm bridge from his 85046B.  Note the four mounting holes, circled in red on the case "lid".  This are missing from the 50-ohm 8505A unit on the right.

As Dave points out, the fix is straight-forward.  Just swap the two lids.

(I don't recall having this issue, myself.  But just in case I did and forgot about it, I'm glad Dave reported it.)

Note (8 Octobor 2020):

For another take on modifying an 85046B to 50 ohms, see this blog post:

http://k6jca.blogspot.com/2020/10/hp-85046b-conversion-to-50-ohm.html

Caveats!

Standard caveats apply!  Know what you are doing.  Don't assume what I've written is correct -- I might have mistyped or made other mistakes.

Building a Bass Guitar Kit, Part 3

(You'll find Part 2 here: (click here!))

OK -- the body is painted.  All that is left now is to sand and polish it.

As with the painting described in the previous blog post, I will strongly recommend John Gleneicki's book, "How to Create a Factory Finish with Just a Couple of Spray Cans!".  There are also some YouTube videos you can watch (for technique).  You'll find plenty on YouTube.  One series I like is by Joseph Tubb (although much of what he does in his series is not applicable to this project).  But for sanding and polishing technique, I recommend checking out parts 7 and 8 of his series.

Part 7 is here: 

(Click HERE for Video)

And part 8 is here:  

(Click HERE for Video)

I used sandpaper grits of 600, 800, 1000, 1200, 1500, and 2000 (all sanded wet, not dry).  These finer grits were available at the same auto-paint store where I purchased my paint.

(Click on image to view in its entirety)

Here are examples of the shine as I worked.  Note that the reflections of straight edges aren't exactly straight, indicating a very slight waviness in the overall finish.  I'll try to do better on my next body!

(Click on image to view in its entirety)

One problem with using wet sandpaper -- if you aren't careful, water can get under the paint and cause swelling.  Here's an example of what happened when water got under the paint at one of the holes where I'd originally screwed the body to the "stick" (which was then removed for these last sanding steps):

(click on image to view in its entirety -- the problem is to the right)

I also had water get under the paint at some of the pick-guard screw holes.  Fortunately, drying out the area with heat (and applying pressure, such as pressing hard with thumb) can bring the raised areas back down.  I used an incandescent bulb about 6 inches from the surface to dry out these types of mistakes.

By the way -- you might first try plugging holes (and covering open areas, such as the one above) with, say, candle wax, to waterproof them.

Another caution:  if using a wood sanding block, the wood can warp if it gets wet, and your flat block will no longer be flat!

After sanding, I used a swirl remover (Mequiar's, shown below), follow by a 3-M rubbing compound (not shown).  Both were purchased at the Auto Paint store.  The foam polishing pad came from Stewart-MacDonald.

(Click on image to view in its entirety)

When the body was polished to my satisfaction, it was on to final assembly, followed by bass setup.

For bass setup, I recommend first checking out the four great videos by John Carruthers on YouTube, in which he explains the steps necessary to setup a bass guitar:

First:  Truss Rod Adjustment:   

(Click HERE for Video)

Second:  Bridge Action Height Adjustment:     

(Click HERE for Video)

Third:  Nut Action Height Adjustment:     

(Click HERE for Video)

Fourth:  Intonation Adjustment:   

  

(Click HERE for Video)

For reference, here's my summary of the setup steps shown in the four videos above:

1.  Truss Rod
     o  Capo at first fret
     o  In playing position, fret the E string where the neck joins the body (16th fret?)
     o  At about the 7th fret use a 0.015" feeler gauge to measure string height above fret.
            To raise string, turn truss rod counter clockwise.  Opposite to lower.

2.  Bridge height
     o  Remove capo.
     o  In playing position, at the point where the neck joins the body (again, 16th fret):
            Adjust E-string saddle screws so that the string is 4/32" above the fret.
            Adjust A-string saddle screws so that the string is 3.5/32" above the fret.
            Adjust D-string saddle screws so that the string is 3.5/32" above the fret.
            Adjust G-string saddle screws so that the string is 3/32" above the fret.

3.  Nut Action Height
      o  For each string:
             Measure height above the first fret.  If greater than 0.022":
                  Loosen string and remove from nut groove.
                  With appropriate file, file in a slightly downward direction (towards tuner) until

                  desired string height reached.

4.  String Length
       o  In playing position, adjust the Saddle Length Adjusting Screw so that the open note and

           the fretted octave are the same.

By the way, during the final assembly and setup I found a few more problems:

1.  Some pick-guard screw holes are stripped (nothing done at the moment, the screws seem to be holding fine).

2.  Truss Rod difficult to adjust.  This neck's truss rod seems to be angled down slightly, so only the short end of the hex driver can engage it, rather than the long end.  Unfortunately, the small diameter of the hole in the wood means that the hex driver can only subtend a small angle of movement when adjusting the truss rod.

3.  During setup, the E string saddle bottomed out.  I fixed this by raising the neck slightly with a shim in the neck picket made with two back-to-back business cards (to get the appropriate thickness):

(Click on image to view in its entirety)

4.  While tuning, I found that the D-string was a little too wide for the slot in the string tree, and it would stick in the slot while I tried to tune it.  The slots were also a bit uneven and had sharp edges at the slot ends (where I was worried about the wire catching).  So I smoothed the front and rear slot entrance/exit edges and widened the two slots with a small file.

Here are a couple of pictures of the finished Bass:

Conclusion:

The bass kit was much more work than I anticipated, from fixing problems that originated at the factory (in China, I believe), to painting the body and dealing with all of the little heart-stopping issues that arose (runs, sand-throughs, etc. etc. etc.), to the extra expense of new strings, guitar-specific tools, etc.

So I have to ask myself, was it worth the effort?

For me, the answer is, without a doubt, yes.

Sure, the kit had numerous issues, but because of these issues, it provided an invaluable (and inexpensive, compared to the price of quality basses) learning platform.  Now if I need to do a bass guitar setup --  no problem!  Frets uneven?  I can handle it.  Sealing, painting, and finishing the body?  A lot of work, but I can now get a color scheme I like, rather than one forced upon me by a guitar's manufacturer.

In short, I'd do this again.  But next time I would prefer that the kit be a lefty PJ bass, or better yet, a lefty Rickenbacker knockoff!

However, if your goal is simply to purchase an inexpensive bass, my advice would be to find a used one.  With the tools and paint that I purchased, I easily spent several hundred additional dollars above the price of the original kit.  For that kind of money, you can get a decent used bass.

I would also like to point out that this kit is a left-handed bass kit, and it's quite possible that a number of the issues I mention in this and previous posts are due to the fact that it is left-handed and thus the workers might not have had experience with any changes-to-procedure that might have been required for the manufacture of the left-handed body and neck.  In other words, the right-handed kits might be better!

Disclaimer:

This was my first time doing any of this:  fret leveling, painting, etc.  Before you tackle your own project, do your research!  Don't depend solely upon my experiences.


Links to Bass posts of mine...

Sonic Blue Bass (part 1 of a 3 part series)

Mellow Yellow Bass

Short-scale Telecaster Bass

Bass Guitar Painting Jig

Repairing a G&L Butterscotch Blonde Paint Chip

G&L ASAT Bass Strap-button Extender

Building a Bass Guitar Kit, Part 2

(You'll find Part 1 here: (click here))

OK -- Problems with the body have been fixed, now it's time to paint the body!

First, what paint to use?

Do I go with lacquer rattle can paint from the local hardware store?  Or how about a Nitrocellulose finish?  Or perhaps auto paint?  Or normal house paint?  And can I use one type of paint and another manufacturer's clear coat?

I started researching the web and I was soon confused with conflicting recommendations and advice -- a true plethora, and not in a good sense.

Fortunately, I came across a book that was a huge help in winnowing out the useful information from the noise:  "How to Create a Factory Finish with Just a Couple of Spray Cans!", by John Gleneicki.

For me, a neophyte painter with little experience, this book was GREAT!  John explains the different types of paints (enamels, acrylic lacquers, and urethanes), their pluses and minuses, and gives some simple rules of what not to do.  For me, this information was well worth the price of the book.

He also spends quite a bit of time discussing the steps and techniques that should be followed when painting with spray cans.  Again, for me, this was all valuable information.

I decided to go with an auto-body polyurethane paint and clear coat, rather than, say, nitrocellulose (although that is a more classic finish), because I was worried about the nitro's durability and also its tendency (or so it seemed to me) to yellow with age.  Although auto paint was more expensive, it also dried much more quickly (days compared to a month or two).  That convenience, and the fact that many guitars are now finished with polyurethane, pushed me in that direction.

 As for colors?  For me there was no doubt:  Sonic Blue!

So off to the auto paint store (I went to one in Sacramento) to purchase my materials, shown below in the order in which they were applied:

• The first can is Spray Max 2K Glamour High Gloss Clear Coat, used to seal the body of the bass guitar before primer or paint are applied.
• The next can is white primer.  I used Transtar 4633 White Primer (the auto-paint store clerk told me there would be no issue using this with my color coat or with the Spray Max clear coat).
• Then the can of the urethane base color:  Sonic Blue, mixed at the store.  Sonic Blue originally was a 1956 Cadillac color, and I gave the man at the counter the Du Pont Color Code for that color (code: 2295).  Interestingly, when he printed the label for the can, it said "Fender Guitar Company," not Cadillac!
• Followed by two additional cans of the Spray Max 2K Glamour High Gloss Clear Coat.

Eye protection and a respirator are shown, too:

(Click on image to view in its entirety)

Here are two more pictures of the Sonic Blue label on the can:

(Click on image to view in its entirety)

(Click on image to view in its entirety)

The body, drying, after being sprayed with the first can of clear coat (sealer/fill coat):

This layer is meant to seal the body and fill the pores (needed, because of prior sanding).  It was then sanded down to a smooth surface and the primer applied:

The primer was then sanded and the color coat applied.  Note the respirator.  Use one!

The Latest in Summer Fashion

When painting, do NOT hold the can over the body as I'm doing here if trying to get to the bottom of the guitar, because...

...a paint blob might fall on it!!!  Look for the dark streak in the center of the photo.  Don't worry, I and the paint job recovered (after my heart restarted).

(Click on image to view in its entirety)

Base coat applied and drying:

One of the problems when painting outdoors, especially under tall pine trees, when the wind is blowing!  Fortunately, I was able to flick these two pieces off with a needle.  But another hear-stopper.

This I couldn't flick off.  Oh well!

Following the color coat, the first can of two cans of clear coat was applied.  Note:  the color coat was not sanded before the clear coat was applied.

A run following application of the first can of clear coat.  Fortunately, following the steps in Gleneicki's book, this is very easy to fix.

(Click on image to view in its entirety)

While sanding the first clear coat, I accidentally sanded through it, the base coat, and down to the primer.  No way to recover, as I had no more base color paint.  Fortunately, the areas were all very small and the white primer was similar in color and luminosity to the Sonic Blue.  But I decided to apply a third can of clear coat, because, clearly, I had not applied enough along the bottom of the bass with the first can -- this area is the most difficult to reach if holding the body by the stick attached to the neck pocket, and so careful attention must be paid, as I discovered!

(Click on image to view in its entirety)

Although, difficult to see in the photo below, the last can of clear coat left little lumps in the paint under the pickup pocket.  This is better seen in the next picture...

(Click on image to view in its entirety)

...here (below).  Look closely -- you can see the little zit-like lumps left by the last can of clear coat, brought to relief as I started sanding.  I believe their appearance was because I was determined to use everything in that last can, and this "stuff" came out at the very end.  Next time, I'll stop a bit sooner.

(Click on image to view in its entirety)

Fortunately, they weren't a problem, as they sanded out (and with three cans applied, there was plenty of clear coat on the body, so no worries about sanding down (and through) the color coat).

And here's the body, awaiting sanding and polishing.

By the way, I strongly recommend that you first plan out your steps and then make a checklist so that you are sure to follow them.  The checklist will also help you remember what you had done if you decide to paint another body in the future.

Here's mine.  From it you can get an idea of the steps I took with each can of paint, and how long I waited between each.

(Click on photo to enlarge)

Disclaimer:

This was my first time doing any of this:  fret leveling, painting, etc.  Before you tackle your own project, do your research!  Don't depend solely upon my experiences.

Next Installment:  Sanding, Polishing, and Assembly! (click here!)


Links to Bass posts of mine...

Sonic Blue Bass (part 1 of a 3 part series)

Mellow Yellow Bass

Short-scale Telecaster Bass

Bass Guitar Painting Jig

Repairing a G&L Butterscotch Blonde Paint Chip

G&L ASAT Bass Strap-button Extender