Routing a Painted Body

[Bassinthemudd]

I've got a body that I'm putting a new pickup configuration in. One pu cavity will be concealed by a pickguard, but the other won't. I'm not sure if the paint is unusually brittle, or if it's normal. When I was checking how the neck fit into the pocket, it took a little force to get it in. I thought, "wow, super nice snug fit!" Then I pulled the neck out of the pocket. I was trying to be gentle, but a small piece of paint dislodged when the neck came out. Also a chip that didn't appear in the listing photos is on the upper horn. Easy touch up advice will be appreciated, but I'm uncertain about how durable the paint might be. This body is old stock from the Peavey factory, so it's been sitting for about 20 years, and could have failed to become a completed bass for many reasons. If I decide to keep the paint on this bass, I'm wondering about how to route the pickup cavity. My uneducated guess is to hot knife the outline. Any advice will be appreciated.

 

[dwizum]

Those chips look like good candidates for CA drop fills.

For routing on painted bodies, If I am concerned about the durability of the paint, I use a down cut spiral bit and climb cut.

 

[T_Bone_TL]

"Authentically distressed!" Thick plastic finish that appears to be poorly bonded (20 years in a presumably unconditioned building in Mississippi might prove a tad less than ideal as storage goes) - good luck with that, or get out the heat gun or beltsander and go to town getting rid of it, IMHO.

Pre-score the routes to contain chipping. @dwizum bit suggestion also reasonable.

 

[Bassinthemudd]

"Authentically distressed!" Thick plastic finish that appears to be poorly bonded (20 years in a presumably unconditioned building in Mississippi might prove a tad less than ideal as storage goes) - good luck with that, or get out the heat gun or beltsander and go to town getting rid of it, IMHO.

Pre-score the routes to contain chipping. @dwizum bit suggestion also reasonable.

Yeah, I've been thinking about removing the paint. But, I really like the color, and don't mind some imperfections. I removed the green sparkle paint from a different Peavey (same model: G Bass.) It was my first time using a heat gun. It worked great. I wish I knew how much force was needed to create the chip on the horn. I am considering doing some stress testing on the back.

 

[Matt Liebenau]

Good suggestions. Down cut bit, score the finish with an Xacto knife or something similar.

 

[TerribleTim68]

I would also recommend putting down a layer of masking tape first, then score your edges through the tape and then route it. The tape will help hold the edges intact a little better. Woodworkers use that trick a lot to avoid tearing out edges, no reason why it won't help here too. Just be sure to peel the tape towards the edge, not away from it, when you are done.

 

[bigtone23]

I am a hack router operator, but had good luck by taping the area I don't want to rout off, then scoring the paint alone the line I want to rout.

 

[58kites]

I am a hack router operator, but had good luck by taping the area I don't want to rout off, then scoring the paint alone the line I want to rout.

Yeah, painters blue tape and route, no problems.

 

[BlzBob]

Another thumbs up for @dwizum 's suggestion. I may have just gotten lucky but I used a Diablo DR75102 Up cut bit and I was happy with the results. Routed in a battery box chamber for a preamp. The thumbnail shaped goof up was my fault.

 

[Bruce Johnson]

One more note about routing down through a paint finish:

Modern polyurethane and polyester finishes, as used on most instruments these days, is really tough stuff. It can be cut and machined easily to a clean edge. When you have problems with chipping or ragged edges, it was usually caused by the wood underneath. The router bit grabbed into the wood and kicked some of it upward. That's what actually breaks the layer of paint and knocks a few chips up.

The lesson is: use the router to cut through the paint itself first, then very gently cut down into the wood underneath. Lock down your template, and make the first pass with the router barely 1/64" or less deep. Just barely cutting through the paint. Unless the paint is badly bonded down, it will cut to a nice clean edge. Then continue on with several more passes of 1/64"-1/32"" in depth each. Once you are down in 1/8", you can start cutting 1/16"-1/8" per pass the rest of the way down. Lots of light shallow passes. Don't try to hog it all out in several deep passes. The hogging is what kicks the wood upward, and chips the paint.

 

[Big B.]

One more note about routing down through a paint finish:

Modern polyurethane and polyester finishes, as used on most instruments these days, is really tough stuff. It can be cut and machined easily to a clean edge. When you have problems with chipping or ragged edges, it was usually caused by the wood underneath. The router bit grabbed into the wood and kicked some of it upward. That's what actually breaks the layer of paint and knocks a few chips up.

The lesson is: use the router to cut through the paint itself first, then very gently cut down into the wood underneath. Lock down your template, and make the first pass with the router barely 1/64" or less deep. Just barely cutting through the paint. Unless the paint is badly bonded down, it will cut to a nice clean edge. Then continue on with several more passes of 1/64"-1/32"" in depth each. Once you are down in 1/8", you can start cutting 1/16"-1/8" per pass the rest of the way down. Lots of light shallow passes. Don't try to hog it all out in several deep passes. The hogging is what kicks the wood upward, and chips the paint.

I do this on all the routes on my basses. Especially things like pickup routes that need to be flawless. I start every cut with a 1/16"-1/8" pass to essentially score the outline of the opening. Once you have a clean edge on the surface you are far less likely to pull a chip away with the router when you cut deeper.