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Jazzmaster Remaster (DIY nitro finish)

Discussion in 'Luthier's Corner' started by DC in ATX, Sep 14, 2020.


  1. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    Picked up a loaded Warmoth body on the classifieds because it seemed like a fun pandemic project. Based on the cost-to-component ratio, I wasn’t too surprised to find that the advertised “just add a neck” was far too good to be true. Most glaringly, the DIY paint job looked to have been a first attempt at wood finishing.

    I don’t have a full before picture, but you can see some of the finish problems here:

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    The motto I was taught is: “A good paint job is 80% prep work.” This Swamp ash body from Warmoth had never been sanded or had the wood grain filled prior to primer and paint. So the finish was telegraphing all kinds of imperfections.

    The good news is that a bad DIY paint job is easy to strip. I used SmartStrip, which is very mild and easy to work with. (Just give it time to work, and Bob's your uncle.) I also discovered that the previous owner paid extra for a 1-piece swamp ash slab body—and then made the odd decision to bury it behind paint. Very curious. (If you want a painted bass that doesn’t require grain filler, buy a 2-piece alder body.)

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    After studying early Jazzmaster guitars, I had picked up a 70s-style blocked and bound Allparts bass neck for this project. So I am going to finish the body to suit that neck, which is leveled, dressed, and ready for hardware. Many of the vintage Jazzmaster guitars have a sunburst finish, so I decided to finish this Swamp ash body accordingly. Given that it is a nice 1-piece slab, a semi-transparent finish is appropriate.

    Since I don’t have any specialized gear or a spray booth, I’ll be doing a DIY 3-color sunburst using the StewMac spray can lacquer kit. Here’s the bass after sanding, grain filler, and a vinyl sealer clear coat:

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    I’ll start building nitrocellulose lacquer coats tomorrow and document my steps. There are some good resources online for doing a diy sunburst. I’ll be employing some techniques to work around the deficiencies of spray cans vis-a-vis a professional spray gun.
     
    Last edited: Sep 15, 2020
  2. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    For the future traveler down the road to a DIY nitro finish, Lone Star Guitars—out of the Netherlands—has one of the best step-by-step tutorials online for doing a DIY nitro finish without any specialized tools or materials:







    Due to the popularity of this content, Will at Lone Star Guitars is flooded with more guitar finishing information requests than he can respond to. However, he was kind enough to send me these tips and process recommendations for doing a DIY sunburst finish using spray cans:


    "As for the sunburst, yes it’s definitely possible using spray cans. It is however a little bit more difficult since the spray pattern from a spray can is less consistent than that from a spray gun. Nevertheless, it is definitely possible to create a perfect sunburst using spray cans. Some advice:
    • Start by creating a very solid base layer (transparent nitro sanding sealer) first. There can be no imperfections whatsoever in this base layer! No unfilled grain, pitting, etc. It should be perfect. Any imperfections that need to be sanded out in a later stage could completely ruin your sunburst.
    • Next, create a solid vintage amber finish. Again, it should look perfect.
    • Spray the sides of the body black (you can mask the front and back of the guitar, I personally don’t but then again I do use a spray gun for this).
    • Use Tobacco brown to blend the black into the vintage amber.
    • You can use some fine sandpaper to sand off any overspray (I’d recommend 800 grit sandpaper or finer).
    • The sandpaper can be used to some extent to ‘shape’ the sunburst (although this required some practice).
    • When the sunburst looks good, apply a generous amount of clear coats. You don’t want to be sanding through the clear coat in a later stage! Again, this could ruin your sunburst.
    A good beginners guide can be found here as well:

    How to spray a sunburst using aerosol cans | stewmac.com

    They spray the sides first, then the amber. I do it the other way around but both can work just fine. Since this is your first time be prepared to sand off the sunburst and reapply a couple of times (if you’re not happy with how it looks obviously). Nitro is easy to sand off and you might end up with a much better finish. Practice makes perfect!"


    Prior to receiving Will's email last night, I was preparing to follow the process in the StewMac link above. However, I am going to start with clear base coats instead. I spent some time this morning looking for and filling any pinholes in the grain. Once that dries and I remove the film residue with alcohol or similar, I can start applying clear lacquer, starting with a "dry" tack coat, followed by 2 or 3 wet coats today and tomorrow, if need be.

    The nice thing about starting with a clear base coat is that this step could reveal some potential problem areas. It looks perfect now, but the proof is in the application of lacquer. If I spot any pinholes in the clear coat, I can address these areas before the color coats. You can fill pores to some extent with lacquer, both by building spray layers or by applying a tiny touch up coat with a brush. Lacquer is an inefficient way to fill these imperfections. Hence, the pore filling and sealer steps. But if you build up enough lacquer, you can fill and then level sand to achieve a perfect base. That's basically my goal over the next two days.

    (It's a small and upside down world after all: I wrote to Lone Star Guitars from the Lone Star State, in part, because I was curious about where Will lives. My family spent 4 years in the Netherlands when I was 11–15 years of age. That's where I first picked up the bass, in fact. Turns out his shop in Geldermalsen is 20 km from where we lived in Den Bosch.)
     
    Last edited: Sep 15, 2020
  3. As a Texan, I'm just pausing to take a moment to recognize all of the guitar builders who somehow name their businesses after Texas. :cool:
     
    DC in ATX likes this.
  4. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    Not specifically relevant to the DIY-aerosol-can crowd, but this is freaking awesome sunburst content—complete with Bob Ross references—from the Fender Custom Shop:



    Super cool to see the pro setup and technique.

    EDIT: Sorry wrong link previously. Correct video posted.
     
    Last edited: Sep 16, 2020
    rwkeating likes this.
  5. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    To play it safe, I built up a clear coat on top of the sealer. That did allow me to identify and fill some pinholes that might have been a PITA later.

    This is after 4 thin clear coats and two vintage amber color coats:

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    I am definitely erring on the side of drier rather than wetter coats. So I will be applying more coats than might be typical.

    Main lesson today is that color coats are best applied outside of the ad hoc spray booth that I created in our semi-enclosed carport—because the light is so much better. That work process forces me to hold the piece by the handle rather than spray it in a hanging position, which helps the coats come out more even. So for the color coats, my "spray booth" is more of a drying room, which is fine.

    I want to reserve the right to do some Amber over the sunburst, as a blend. But I may need to do a little work in the morning to even out the vintage amber, especially on the front. Once I have the “field” color where I want it, I’m going to apply more clear coats. This clear layer will basically be a sacrificial protective layer. It will allow me to clean up any of the burst colors and applications without sanding into the amber.

    I have a work process in mind that should be reasonably forgiving, but better safe than sorry.

    This is the kit I am using, btw:

    ColorTone Aerosol Finishing Set for 3-Tone Tobacco Sunburst

    At the price point, I wish StewMac included a couple of the upgraded aerosol spray nozzles, which allow for a vertical or a horizontal spray orientation.

    [Update: They do provide one of these tips. It was installed on the black nitro aerosol can. The other cans have the standard spray nozzle.]

    Otherwise, no complaints with the contents or quantities. I'll probably run through all of three cans of clear nitro. But I'll have some other materials leftover, to be sure. I realize that kits are not a good value in terms of quantities, but in terms of convenience it seems to include the application-specific nitro finish supplies from start to finish.

    In terms of general supplies, I have a fair amount of wood finishing materials at home from other projects. The main thing I will be ordering separately for thIs finish are buff and polish products.
     
    Last edited: Sep 19, 2020
    Paco Leon, wraub and Robbie D like this.
  6. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    After evening out the amber field color, I applied a couple coats of clear. Then I sanded the clear coat using 800-grit, as a leveling step, and added a couple more clear coat layers. With the amber protected, I moved to the black edge—the first step in the burst.

    Because the using spray cans outdoors is such an imprecise working condition, I am going to rely on masking as an aid. I started by pilfering my wife’s roll of tracing paper, with her permission. After cutting two oversized rectangles of tracing paper, I taped these to the top and bottom, respectively, and used a graphite pencil to find the edge of the round over. I then used an exacto knife to cut the paper to this line. Additionally, I cut out some material in the field in order to tape the masking to the wood. This is is the proof of concept on the Dining room table:

    2B22E8A3-7C28-4A33-8B4C-4CC076E0C5A2.jpeg

    The masking template worked pretty much as expected. The nice thing about tracing paper is that you can basically see what is underneath the paper during the prep stage. The bad thing is that it is so lightweight that any breeze—or even a misguided aerosol burst—could lift the paper off of the body.

    On the one hand, you want some edge flutter to help create the fade in the burst. On the other hand, you need to know that the masking is going to stay put. I applied some additional painters tape around the edge of the masking as a sort of ballast.

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    You can’t tell from these pictures, but the body is sitting on a lazy Susan at this point. That definitely helped with this step. You can see a little hint of burst taking shape:

    8EB6E3F1-39CA-47F2-93A2-8B440CED48CF.jpeg
     
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  7. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    The trace paper as masking works okay. I’d say that 90% of the edge comes out great. I had one or two spots with an unacceptably hard transition between black and amber.

    The easy work flow fix is to use a rigid mask that floats above the body. I used my trace paper templates to cut a mask out of matte board (for framing art). My first thought was to drill some tiny holes in this template and insert flat head finish nails into these holes. That way you can adjust the height off of the body slab based on the length of the nail shank. I may still use this technique for the tobacco and cherry bursts.

    To fill and blend in the black, however, I really just want a little separation between the matte board and the body. So I used some round cork pads that are probably 3/32” thick as my spacer.

    5AB57C1E-F353-4241-9CCE-8AF0ABA8E261.jpeg

    The little rockler pucks are handy during sanding and finishing, as they elevate your work on a non-slip surface. Here I am just using them as ballast, to ensure that the matte board mask stays in place while I am spraying. The resulting black portion of the burst is reasonably good:

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    Given the amount of overspray from the aerosol cans, I’m going to make successively smaller matte board masks for the next two colors. In theory, I could simply cut the current mask smaller and smaller. But, I may need to rework the piece if things don’t go as planned. So I’ll cut separate masking boards to play it safe.
     
    Last edited: Sep 19, 2020
  8. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    Making the fade. First, I traced an interior line around the large masking board. Then I transferred that outline to tracing paper. Then I transferred the contour to a new piece of matte board.

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    After cutting out the masking board for the tobacco, I used cork spacers to float the matter board off of the slab.

    D08A50EF-EF75-49B8-ACFC-0C7F1BBFB2E6.jpeg

    For the black boundary, I sprayed from the outside in, in order to get good coverage on the exterior edges. For the tobacco and cherry fades, you really want to spray from the inside out, in order to maintain the black edge.

    Burst is looking better after one coat of tobacco.

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    Don’t mind any overspray in the field. For example, you can see the outline of my spacer on the top. That’ll come off with light sanding in the morning. That’s why the sacrificial clear coat is on top of the amber.
     

    Attached Files:

    Last edited: Sep 19, 2020
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  9. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    Day 7 (since the sealer coat). Cherry red burst. Looks alright.

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    Last edited: Sep 20, 2020
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  10. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    I’m giving up on the burst.

    The good news is that the level sanding I’ve done is producing great results. If I keep building layers, I’ll have a primo finish.

    The bad new is that no matter how many tricks I try, I can’t tone down the “clown burst” and get a nice fade, especially on the red. Going backwards too many steps is no guarantee that I can get the burst right. And I’d probably need more black and tobacco burst than what I have left on hand.

    The easy pivot is to change to an all black finish. I am pretty confident that I can get a legit pro-quality finish with a solid color. The majority of my basses are black—so it’s also on brand in terms of my color preference.

    In terms of lessons learned, I posit this:
    • It is entirely possible to do a diy burst nitro finish using aerosol cans
    • It is entirely possible to do a quality diy nitro finish outdoors
    • It is tricky to do both
    For best results on the burst, you want to freehand the colors. That’s not wise if there’s any wind. Using a mask to compensate for the wind can lead to clown burst. Someone can do it. But I am not quite that skilled in the ways of aerosol spray cans.
     
    Last edited: Sep 22, 2020
    Matt Liebenau likes this.
  11. Beej

    Beej

    Feb 10, 2007
    Vancouver Island
    It's pretty good for your first try though! This is one of the better vids I've seen showing the technique - should be...it's from the Fender Custom Shop. :D

     
  12. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    Right, I linked to that video previously. It's fun to watch. With the right gear and years of experience, it's easy peasy. Working within the constraints of more pedestrian gear and an uncontrolled environment is a tough combo. Dyes might have been the better approach. Solid finish should be easy. I love working the hardened nitro.

    My usual MO is to avoid spray film finishes in favor of wipe-on penetrating finishes, like oil or shellac. If I minimize enough of the variables that can go wrong, my finishes come out great—or at least acceptable.
     
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  13. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    Progress update:

    F0AFAC70-5176-4949-A997-643F7F184414.jpeg

    Black nitro coats are all finished at this point. I sprayed the remnants from these cans into a mason jar for touch up. Last night, for example, I used plastic toothpicks to lay some black into pinholes in the finish.

    I’ve applied one can of clear coat over the black. During level sanding this morning, I got the first real glimpse of what the final finish will look like, as there are fewer and fewer low spots. I have two additional cans of clean nitro and will probably use both for the additional leveling. If the weather holds, I may be finished with the nitro applications this week and moving on to the curing stage.

    If I had a magic undo button, I would either: A.) spend an extra day or two prepping the grain filler; or, B.) skip the grain filler altogether and do a matte finish that showcases the grain figuring through the solid finish. Obviously, Option A is most consistent with the Fender universe. Personally, I love the Sandberg matte finishes, as an example, that showcase the grain. Too late for that in this case, but I like that approach. It looks cool and it streamlines the work.
     
    Last edited: Oct 5, 2020
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  14. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    Build it up—and knock (sand) is down. This is the first new coat of the day:

    041325A0-CE18-4585-996B-98CF93C92911.jpeg 4A181F59-0065-4C44-837B-5943E6F562FC.jpeg

    I’m at the stage of the project where there are fewer and fewer low spots after level sanding. That is satisfying.
     
  15. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    Getting closer. Still a day or two remaining of applications. Today, I worked the body through the entire series of micro pads:

    70BE55D4-3879-454E-B927-BB4E2BA735A9.jpeg
     
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  16. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    The wait for the cure...

    Applied final coats of nitro this afternoon:

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    I decided belatedly to do a satin finish. So I actually sanded down some perfectly good clear coats, applied another base coat of black, and then topped that with satin nitro.

    While that rework cost me some time, I just realized that opting for the satin finish will save me a bunch of work on the backend. I’ve read different things RE: whether or not to polish a satin finish. The matte finishes that I prefer are not polished and have the “spray” texture. That being the case, once this has had a few weeks to cure, I am going to start assembling the bass.
     
    Last edited: Oct 21, 2020
    Beej likes this.
  17. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    After a detour into 100-year-old house projects, I am back to the partsmaster bass project.

    The body and electronics are basically finished and ready for the neck. You can start to see what the Black Rose will look like when finished here:

    7C24E1FB-F506-4A41-A938-20603B9F7B83.jpeg

    Unfortunately, it didn’t occur to me to install and topcoat the decal before the holiday break. So now that 30 minutes of work per day spread across three days is in my critical path, so to speak. Ideally, I can get the neck installed the first weekend in January and then slot the nut and finish the set up the following weekend.
     
    Last edited: Dec 28, 2020
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  18. Dec1975

    Dec1975

    Aug 30, 2006
    Cedar Park, TX
    It's looking great! Did you end up polishing that satin finish?
     
  19. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    Yes! Good eye.

    It was a tactile decision more than anything. I liked the way the DIY matte finish looked. I wasn't crazy about how it felt to the touch. So I took the finish through all of my wet-dry sandpaper and micro-mesh grades.

    I have never had my hands on an instrument with a matte finish. But I suspect that a pro finish would have a better tactile feel than the spray can finish.
     
    Last edited: Jan 14, 2021
  20. DC in ATX

    DC in ATX Supporting Member

    Apr 21, 2020
    Austin, TX
    She’s alive! Since my last post, I have clear coated the decal, attached the neck, installed machine heads, and—as of yesterday—slotted the nut.

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    I still need to do a proper fret level and dress and fine tune the setup, but it’s pretty close right now. Using the StewMac nut slotting gauge, I took the nut inside of 0.03” at the first fret. So, I can bring the action down a bit after I level and dress the frets.

    It took me a minute to grok how the active four-know controls work, as I don’t have a blend knob on any of my other instruments. Once I figured that out and set the pickup heights, it sounds great. Very articulate and musical.

    Obviously, this offers way more on-board tone control and range than my go-to p bass. I was hoping that this would complement rather than duplicate what I can get out of my other basses. I’d say this project is a success on those grounds alone.
     

    Attached Files:

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  21. Primary

    Primary TB Assistant

    Here are some related products that TB members are talking about. Clicking on a product will take you to TB’s partner, Primary, where you can find links to TB discussions about these products.

     
    Apr 17, 2021

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