My first "build". P-bass to Scroll bass. Some info/advice please?

Discussion in 'Luthier's Corner' started by GKon, Dec 28, 2014.

  1. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    Hi to all,

    I have some questions for you experienced luthiers. I hope that you will be willing to indulge me and answer some of my rookie questions. (I must add that I'm inspired by Mapleglo and Suresh on this one!)

    I've never built a musical instrument before, but I have done basic carpentry over the years, as well as having worked with metal when I used to build and repair motorcycles (welding, soldering, lathe and mill work, etc). I know that building a bass requires its own set of skills (and tools) but I'm simply pointing out that I'm not a stranger to building things and how to use various hand and power tools.

    Now, I'm not looking to build something from scratch (WAY above my skill, tool and patience level), but I am considering taking an inexpensive (89 Euro) P-bass kit from Thomann:

    to turn it into my own version of the Ampeg scroll bass/Eastwood EEB bass:

    I plan on using all or as much of the hardware that is provided with the kit (p'ups, pots, wiring tuners, bridge, output jack, strap knobs)

    The first main issue I see is having to fill in the route for the wiring that the P-bass pickguard would cover, so that I could cut out the scroll design of the S-bass (S for scroll ;) )

    I'm assuming this will be possible to do, of course with some effort and a good amount of glue?
    Any suggestions on how to go about it?
    It seems that I don't necessarily have to fill in the entire route as the new pickguard I will have to make will cover a good portion of the unused routed portion. Speaking of pickguards, what do you all recommend to source as material for one (I will do a search here on TB as I know this has been discussed before).

    That leads to the next question. Is it "better" to fill in the entire unused routed cavity prior to placing the new pickguard (I assume for reasons of sound/sustain and also for mounting points for the new pickguard, although I can just glue blocks in place if it's simply for mounting points) and the route the new cavity as needed, or can I leave the unused route hollow, actually providing a lighter body (although this may lead to major neck dive)?

    My next question is in regards to the bridge/bridge cover/pickguard area. I've never had a look under the bridge cover. I would assume that the bridge is mounted directly to the wood of the bass body, and that the pickguard is routed with an opening to fit over the bridge, and then the bridge cover is mounted on top of the pickguard with the cover screws going through the pickguard and into the wood of the body?
    (Do the bridge cover screws also go through the bridge through mounting holes??? Doubtful, but I need to ask, as I've never owned a bass with a bridge cover).

    This leads me to the question about the headstock. Part of me is considering keeping it as is, simply just reshaping it into a design of my choosing, thus making it more "my" design, and also making it something a bit different than the classic scroll bass(es).

    However, part of the big draw of the scroll bass is, well, the scroll!! (I know the Eastwood doesn't have one, and that's the only thing I don't completely like about it, although I'm not at all turned off by it).

    So, although I don't know if I'm feeling bold enough to try it, I must ask, how difficult would it be for a "newbie" who doesn't have access to a lot of tools, to (I assume) remove the fretboard, cut off the head stock on this neck, create a scarf joint, and then install a scrolled head off of another instrument (perhaps a smaller head off of a double bass, or maybe a cello? I've yet to measure any sizes to see if they are compatible)?

    I apologize in advance if my questions are very basic or are considered too broad or general. As I have no experience, I've tried my best to be as thorough and detailed as possible.

    I look forward to hear what everyone has to say.
  2. Two points.

    Handy people tend to be able to lend their hand to handy things they haven't done before, so if you have done some carpentry before, you will likely do great.

    Rather than trying to make a 'replica' of the ampeg, instead work on doing something inspired by it. So doing your own headstock shape is a great way of doing that.
    Also means you could perhaps do smaller F-shapes that avoid the channels or some such? By all means carry on with your plans, but perhaps before you do, its worth printing out several sheets worth of the photos of the kit, and doodling on top of them till you get something you like the look of.
    GKon likes this.
  3. HaMMerHeD


    May 20, 2005
    That body is basswood, so it will already be very light. If you leave the route unfilled and empty, you will probably end up with a neck-heavy design.

    It looks like the route is a uniform depth across the whole thing, so it should be easy to fill it. Ideally, you should fill it with the same kind of wood, so it should be a matter of finding some basswood lumber (sometimes marked and sold as Linden) and cutting a piece to fit. Since it's your first time, you'll probably end up with some gaps to be filled. The best route for that is sanding dust (not saw dust, it's too coarse) and 2-part epoxy. It makes a thick slurry that will gaps well, and you can sand it smooth. You'll definitely want to paint the thing, rather than a natural finish.

    As for the scroll...I don't think I would start with a P-bass neck if the scroll was my goal, but Bruce may have better guidance if he makes it into this thread.
  4. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    Thanks for the tips and, more importantly, the positive attitude, gmjhowe.

    My typing of this post was as I simultaneously had the idea. It popped into my head, and I wrote about it, so yes, I will definitely
    be going through many drawings, ideas, mock ups, etc. until the final form is taken and made. That and, more importantly, finances
    need to fall into place.

    I agree wholeheartedly, as well, that this will be my version, inspired by the Ampeg, so matching it route-for-route and scroll-for-scroll
    is not going to be a priority. I'm already tossing around some ideas using the already provided neck.

    Gosh, the more I think of this, the more excited I am about it!!
  5. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    Thanks, HaMMerHed, for the tips on how to fill the route. Good info I will add to my new book of building a bass tips!

    For arguments sake, could one not take a large amount of sanding dust, mix it with a 2-part epoxy (is there a special type of epoxy for wood? I've
    only used epoxy for steel) and just fill in the entire route with that liquid mixture?

    I am planning on painting it once it's done. That's going to be a whole other new set of experiences.
    From what I've read here on TB, painting a bass is as time consuming and prep oriented as on motorcycles.
    I've NEVER wanted to be a painter because I'm just not cut out for it (TOO much prep, too many chemicals, etc).
    Not for me. But, I'll do it this one time (famous last words ;) )
  6. HaMMerHeD


    May 20, 2005
    Yeah you could. I wouldn't do it, because I prefer working with wood rather than plastic, but you could go that route. For that matter, you could fill the whole thing with bondo. It's pretty easy to sand and level.
  7. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    Bondo? As in "I have a dent in my car, let me fill it with bondo" bondo? Or is there wood specific bondo? wood specific epoxy?

    If I was to fill with either bondo or epoxy, would there be an issue if/when I cut out an f-hole and it cuts into/through the bondo/epoxy?
  8. mapleglo

    mapleglo Ancient Astronaut Theorist Gold Supporting Member

    Sep 7, 2013
    phoenix, az
    Depending on your access to lumber yards, I'd be tempted to just make a new body. You could likely pickup a piece of ash or alder for maybe $40.00, that wouldn't need to be filled. Basswood would be even cheaper.

    Bondo (yes, "I have a dent in my car, let me fill it with bondo" bondo) would work for fill, but it may leave a witness line, no matter how well it's smoothed. It also expands and contracts differently from the surrounding wood, possibly creating a witness line after the fact. I've seen both successful, and not so successful fills.
    JIO likes this.
  9. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    Hi Mapleglo :)

    Well, given that I have very few tools to work with (at the moment), creating a new body may be out of the question.
    I'll have to see as this project comes to fruition. That's why I'm tempted and trying to use everything that comes with the kit,
    with as little woodworking as possible.

    Also, wood here in Greece is so very expensive! I had no idea, till I moved here. A 2x4 which I could get for a dollar or so in NY
    is about 5 euro here (that's close to 7 dollars or so). So buying a whole piece of wood to make a new body goes against my desire to make
    this as inexpensive a build as possible (I didn't mention that in my original post, but that is one of my parameters).

    I have no idea is basswood is available here to fill the route. I assume I can use another type of wood if necessary?

    I don't know that I'd actually use bondo, but I am fascinated that it's usable on wood.

    I must ask again, the epoxy that's been mentioned, is that a wood specific product?

    When the shops are open tomorrow I'm going to hit up the local DIY center just to see what's available in regards
    to wood, epoxy, paint etc.
    steve_h likes this.
  10. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    Something I just considered.

    I may decide to cut off the horns of the P-body to more closely mimic the shape of the S-body bass.
    If I do end up going that route (no pun intended), I can likely use that wood to fill the route on the
    body. Self sufficiency at its finest.
    kodiakblair likes this.
  11. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    First off, seems like this thread double posted. I'm seeing how I can delete the other one, so as to not incur the wrath of the Mod's ( ;) )
    and so as to not have info split between the two. Moderator, if you can, please delete the other thread with the same title, as I'm having no luck
    figuring out how to do it myself (I don't know if it's even possible for me to do).

    Looks like I'm taking the plunge today and ordering the P-bass kit from Thomann as well as a bridge cover. Some friends are also ordering with me
    so we will end up not paying the flat 20 Euro shipping fee to Greece.

    I've been scouring TB, youtube and the internet for any information I kind find regarding filling routed holes (no luck there), filling
    seams (lots of luck there, same/similar to what Hammerhead mentioned), how to make a pickguard, ampeg f-hole templates (no luck there), etc.

    In my search, it seems that I'm not the first on TB to have this idea! Came across this, which is very similar to what I'm attempting:

    This, which is a full scroll bass from scratch, with lots of good pics and tips:

    And, of course, the website of Bruce Johnson's BEAUTIFUL scroll basses, also with lots of pics and tips:

    Seems like it's do-able, and will be a very big learning process (gosh, how I HATE sanding. Always have, always will.
    Don't get me wrong, I'll do it, and I'll do it well, but I hate it).
  12. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    Well, I just got the Harley Benton P-bass kit.
    All in all, I'm happy with it (still unassembled) and seems to fit the bill for what I want to do.

    The hardware is on the cheap side, but, for the time being, it will suit my needs.

    I've already bought a "Genuine Fender" bridge cover. Seems to fit well over the bridge.

    Now I plan on finding some hi-res photos of the Ampeg and/or Eastwood basses with clear, head
    on shots of the F-holes, so that I can print them out full size and use them as templates to see
    how it all matches up to the P body. After that, I can decide how and how much of the route
    needs to be filled, and if I'm going to cut off the top and bottom horns to match the Ampeg
    body style better (I'm definitely more inclined to do it rather than not, as I like that body style).

    This will be a slow going project due to lack of funds and tools, but I do hope to make some good progress
    little by little.

    IMG_9111.JPG IMG_9112.JPG IMG_9116.JPG IMG_9117.JPG IMG_9118.JPG IMG_9120.JPG
    IMG_9125.JPG IMG_9127.JPG IMG_9113.JPG
    gmjhowe likes this.
  13. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    I'd like to ask a question from the more experienced woodworkers and luthiers.

    As I don't have a router at the moment, but I may have access to a jig saw, would it be feasible to cut out the f-holes with a jig saw and
    then smooth them out by filing/sanding? I know that there would be a consideration of the wood chipping, but at the right speed and with a
    good blade I think I can keep it minimal.

    I have found an inexpensive router that would be worth buying if absolutely necessary, but then I also have to buy the right bit and, if I"m not mistaken,
    they're a little expensive. I'm on a tight budget.
  14. GKon

    Drill a series of holes inside the scroll shape until the shape falls out then sand the edges smooth. I know you love sanding:D
    EddiePlaysBass and GKon like this.
  15. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    Hahahah! Indeed I Do(n't)!!!!! ;)

    Drilling holes and drilling seems to be along the same lines as cutting to within 1/8" of the perimeter and then sanding, no?
  16. Even using a router you are going to need to sand sand sand to get a nice finish. Sure you can sand less and get less of a finish. Patience to do a good job is what makes the biggest difference. Even if that means being patient in waiting to save up and buy a tool. Ideally a nice template following router bit and a template would do the best job.

    However, if I was doing this without, I would seriously contemplate doing it by hand with a coping saw. This involves drilling a starting hole, feeding through your blade, then cutting away. If you haven't used a coping saw before its worth practicing on scrap, you can get a decent amount of movement and control with one.
    GKon likes this.
  17. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    That's a great piece of advice. I have, indeed, used a coping say, but mostly on metal. I VERY much like the idea of doing it by hand because I feel that it will give me a lot more control.
    Thank you for the information!

    You make a point, though, that brings up another question. I've never used a router before. When creating the template that the router will follow, do I use the router on to make the cutouts on the template, and then smooth the template out with sanding? Or do I use, as mentioned, a coping say or jig saw even to cut out the holes in the template and then smooth that out by sanding?

    Edit: And, although I joke about hating sanding, I do realize that it will take a lot of it and a lot of patience to get a nice finish. I may complain about it but I do plan on doing it right, and as best as my abilities allow :)
  18. Hopkins

    Hopkins Supporting Member Commercial User

    Nov 17, 2010
    Houston Tx
    Owner/Builder @Hopkins Guitars
    I have never used a router to cut my F holes. I drill each end with a 5/8" forstner bit and cut out the middle with a scroll saw. My F holes come to a sharp point, and they are narrow so a router wouldn't work well at all.


    A coping saw would work, but it would have to have a very deep throat to be able to get around the top.
    Imaginary Pony, kodiakblair and GKon like this.
  19. GKon

    GKon Supporting Member, Boom-Chicka-Boom

    Feb 17, 2013
    Albuquerque, NM
    Wow, very nice, sharp and crisp cutouts. Thank you for the pic and the info. Looks like I'll be cutting them out by hand, after all.
    I like that, especially because I can comfortably do it on my balcony without causing too much noise and fuss for my neighbors in the building I live in.
    And, buying a scroll or coping saw shouldn't cost too much.

    Would you mind posting a pic of the saw and blade you use, for reference?
  20. Hopkins

    Hopkins Supporting Member Commercial User

    Nov 17, 2010
    Houston Tx
    Owner/Builder @Hopkins Guitars
    I'm sorry, I think you misunderstood what I use to cut mine out. I have a Porter-Cable scroll saw exactly like this one. I don't do them by hand.


    This may work doing it by hand if your body isn't to long. You would have to cut it half way from the top and half way from the bottom since its only 11 1/2" depth per cut.