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Build #3, Thread #1: My New Thinline Bass Guitar

Discussion in 'Tele Home Depot' started by Freekmagnet, Mar 13, 2017.

  1. Freekmagnet

    Freekmagnet TDPRI Member

    61
    Dec 7, 2015
    Ventura County, CA
    Thanks!
     

  2. Freekmagnet

    Freekmagnet TDPRI Member

    61
    Dec 7, 2015
    Ventura County, CA
    Alright, little update.

    First off, let me describe a little bit of my research and development process. At this point, I've wound a good number of coils and assembled a good number of prototypes. On my desk, I have about 20 different coils of varying size, shapes and materials. I'll plop one pickup into the tester bass, rock out on it for a few days, make a few adjustments and if I like what I'm hearing, I'll keep going with it. Sometimes, I'll spend a few weeks with one idea, and decide for whatever reason it's not what I'm looking for. But then, after trying a few other ideas I may (or may not) come back to the previous idea.

    In any case, for a number of reasons, I'm back on the neodymium sidewinder. Initially, and in closing, a lot of it has to do with the form as well as the tone. Because the neodymium are so small and insanely strong, I can build a smaller pickup with lots of output. I found a shape I liked and ultimately discovered that the geometry of the coil is one of the largest contributors to both overall output and tonal characteristics. From there, I was able to make variation after variation using different wire gauges and turn counts. At this point, I'm down to maybe 3-4 different versions of the same pickup that I like and eventually I will select the "final" pickup from this pool - or perhaps I'll even make a slight variation based on one of those pickups. Overall, I like the sound - I have enough bass, mids and high end. The neos render an aggressive sound without being too stiff like the ceramic-based coils. I'd say that they have a lot more warmth than ceramic, but more attack than say, A5.

    After attempting a few different styles of cast shells, I started kicking this idea around:

    [​IMG]
    Basically, the coils will be cast individually and then sandwiched between the steel blade poles. The neos are so strong that it takes a considerable amount of effort to pry the pieces apart, so structurally, I think this will be pretty solid despite being held together primarily by sheer magnetism. The dog ears will then be epoxied on to the sides to really hold them together. The base plate (not pictured) will be also epoxied to the bottom, also adding extra security. I'll wind and cast the coils without the magnets. I can then drill out the core and insert the magnets afterward.

    This form also provides for and solves many esthetic quandaries I've been having throughout this project; first and foremost, there's lots of cool-looking exposed metal. I also changed the spacing of the poles - previously, I had them two to a string like a Jazz Bass pickup. I moved them closer together because A) I'll save about 1/4" of width, and B) once the magnets are in touch with those steel poles, I don't think that the magnet spacing will make much difference in the final outcome.

    I made some originals for this over the weekend and hope to make molds later this week.

    [​IMG]

    Lastly, on another bit of news, I started a little blog about my pickup making about week or two ago. I'll be posting my big forum posts there as well as some additional stuff, like Instagram images, etc. It started as a convenient way for me to keep track of my notes and it went from there. The look for now is completely stripped to just pictures and words - no layout. Part of my day job is in fact, building Wordpress sites. I just wanted a place to post pictures and a few words. I may build the WP theme out later. BTW, the site automatically ads my Instagram shots as individual posts, so those get updates a couple times a week.

    Funktronic
     
    Barncaster likes this.

  3. GerryB

    GerryB TDPRI Member

    49
    May 12, 2003
    Somerset, NJ
    Wow, I JUST started looking into molding pickup covers...what you're sharing is right on time! Thanks so much.
     

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  5. Freekmagnet

    Freekmagnet TDPRI Member

    61
    Dec 7, 2015
    Ventura County, CA
    Cool!

    Just be forewarned: I have yet to actually succeed at making a cast shell - I've had about 2-3 "almosts"!
     
    Arch Stanton likes this.

  6. Freekmagnet

    Freekmagnet TDPRI Member

    61
    Dec 7, 2015
    Ventura County, CA
    I wound the new bobbin with the more closely spaced poles the other night - definitely a better approach than building the bobbin around the neodymium cores. Basically, I glued the blank flanges to the keepers and using the keepers as a drill template, I bored the holes in the blank flanges.

    [​IMG]

    They came out pretty good! I think that drill schedule will work better. It certainly took a less time. Casting and sanding the keeper is still taking a while. I'll have to work on that. I had a little more trouble with flaring. I think having the magnets in there added more gluing surface. If this magnet-less winding procedure works, I might look into making another plate for the winder that sandwiches the bobbin in there so it won't flare.

    Next, I epoxied the wire terminals to the bobbins.

    [​IMG]

    I used those breakaway header pins. You can't beat 'em for cheapness or convenience, although I'm still troubled by this joint; when I solder, the housing heats up enough for the wire to loosen. It hardens back up as it cools, but I can see this being problematic. I'm going to look into making some little mount out of stripboard and try using the right-angle pins instead.

    Next up, resin casting the coil...

    For this pickup, I had to come up with a way to cast a fairly narrow coil in epoxy. I had to do it in such a way so that the magnets would not be covered in resin and the bottom needed to have space for the wire terminals. What I decided to try was to make a two-part silicon mold and cast the coils without the magnets so that I could install them later.

    First, I made a two-part mold. This basically involved making one cast using modeling clay as a filler. I used ball bearings as registration points.

    [​IMG]

    I backed one edge all the way to the side of the box. Leaving on side open, this is where I will actually pour the epoxy into the mold. The wire terminals will be sticking out of the back. Once I poured the Smooth-On OOMMOO 30 silicone casting compound and let it set, I got this:

    [​IMG]

    From which I made the other half of the mold - I'm actually making a couple of different parts here...

    [​IMG]

    Once I go the completed mold, I placed the coil into the mold. I included a couple of nubs to hold it in place so that the coil is suspended in the mold while the epoxy flows underneath it. It's tight enough so that not too much resin goes into the slug holes, but just in case, I added some registered drill marks that would be cast into the piece. This coil hasn't had the terminals installed yet - I just placed it in there for demonstration.

    [​IMG]

    Next, I pour the West Systems Epoxy. I used black Mixol as a colorant. I ended up mixing a little too much epoxy - the whole cast only used 1/2 teaspoon of material! The fixture is to keep the sides from flexing - otherwise, the epoxy will just splooch out of the sides. Note the li'l terminals sticking out of the top left corner.

    [​IMG]

    And here we go!

    [​IMG]

    Not too bad! First, let me disclose that there was a teeny weeny bit of resin in a couple of the holes - I just got too excited and cleaned them out before I took the picture. The sides might need a little sanding and cleanup, but they won't be exposed, so I don't have to worry too much about it. I will have to do some facing on the top part which will be visible. I had the casting in the mold for about 8 hours on a fairly hot and humid day, and the epoxy still seemed a tad soft. I may let it harden for another day before I start sanding the front surface.

    Next up, the dog ears and base.
     
    Mat UK and Barncaster like this.

  7. Freekmagnet

    Freekmagnet TDPRI Member

    61
    Dec 7, 2015
    Ventura County, CA
    I didn't want to jump the gun and reveal my progress with this pickup build too early, but at this point I have more than a year into this design and after today, this felt pretty good. Besides, I prolly won't get to the ears and the base until Sunday. Here's an image of my neodymium bass sidewinder pickup:

    [​IMG]

    I sanded and polished the epoxy parts. I basically sanded it up to 2000 grit. It polishes OK, but I don't know if I can get it up to a gloss. I think that's where CA glue would come int. The bars are just roughly sanded and need sanding and polishing. I'll get to that this weekend as well. I'm really envisioning them in chrome.

    Once I cleaned up my epoxy resin cast bobbins, they looked pretty good. I've been talking a lot of smack about Garolite as a bobbin flange material lately, but I gotta say it worked great. It feathered right into the epoxy.

    [​IMG]

    In addition to the base, my next big quandary is going to be this: I'm going to need to "pot" the space in between the coils and the bars. I left about .005" gap on either side - not a lot, but enough to see daylight through it. There has to be some space in order to assure that the magnets are making full contact with the bars. We'll see. Dripping the clear penetrating epoxy sealer would make kind of a mess. I don't know if I even want to think about pouring potting wax in there.
     

  8. Freekmagnet

    Freekmagnet TDPRI Member

    61
    Dec 7, 2015
    Ventura County, CA
    Moving right along here...

    [​IMG]

    As far as names, I'm thinking it really needs an appliance name. I'd say it's definitely looking pretty toaster-like!

    Anyway, all the parts are made, except I have to actually get the mounting hardware to work. I polished the steel blades by hand, which was long and tiresome.

    The dog ears came out pretty good. The surfaces need a little work, but for now, I'm going to leave it. Most of them will be inside the body of the guitar. Eventually, I'm going to have to make a new mold. Ill worry about it then.

    However, I wanted to point out a cool detail with the dog ears:

    [​IMG]

    I cut these little channels in the original so that they'd lock into this little joint on the coils...


    [​IMG]

    OK, so the next thing I gotta do is figure out how to glue the danged thing together! That is going to be a really cool trick once I figure it out!

    On a side note, I decided I'm going to sell my wide format inkjet printer to my work and use some of the dough to buy something like this:

    http://www.eastwood.com/8-in-bench-shear.html


    It seems like there's a lot of them around for about $100 - $150. There's about 3-4 time a week I find myself thinking, "It sure would be a lot easier to do this with a sheet metal shear instead of using a hacksaw and file to clean the edge."
     
    Last edited: Aug 11, 2017
    guitarbuilder and Mat UK like this.

  9. Raoul

    Raoul TDPRI Member Ad Free Member

    29
    Dec 16, 2016
    CO
    This is simply awesome.

    Despite your thorough explanations, this non-wood stuff is far enough out of my experience zone that I was struggling to envision where your last epoxy work was going.

    So the "reveal" here is all the more magical. Thanks for sharing the whole thought and work processes.
     
    Barncaster and Freekmagnet like this.

  10. Freekmagnet

    Freekmagnet TDPRI Member

    61
    Dec 7, 2015
    Ventura County, CA
    Thanks! I'm really happy that you are enjoying this thread.

    I've come to accept that pickup making, especially if you're walking off the beaten path, is kind of a lonely process. Not too many people make their own pickups and even when they do, they stick with known quantities like P90's or Tele bridge pickups. That's understandable - designing a pickup from the ground up with nothing to use as a basis or frame of reference has been a pretty enormous challenge for me. Like, how is a neodymium sidewinder supposed to sound?

    When I started pickup winding about 18 months ago, I didn't have a concrete idea in my head as far as what the final outcome would be - I just knew that I didn't want to spec my bass with another P or J or MM pickup. Even to this day as this pickup project draws to a close, I'm still kind of making things up as I go along. What's great is that I can pretty much clone the components I created for this pickup to design other pickups. All it takes is a minor change like a different wire gauge, or a slightly wider coil, a single pole as opposed to 3 or just lighter gauge steel bars as poles. All those tiny changes will make a completely different pickup.

    I'll be wrapping up this pickup project fairly soon. Once I have the complete pickup in my hands, I'll be able to comfortably move on to the making stuff out of wood part of the project. I've been kind of held up because the pickup is so tall and wide and I have to really design the bass body around accommodating this piece.

    For the next few days, I have sit down and figure out how I'm going to epoxy that blade and coil sandwich together without making a complete mess of everything.
     
    Arch Stanton likes this.

  11. Freekmagnet

    Freekmagnet TDPRI Member

    61
    Dec 7, 2015
    Ventura County, CA
    [​IMG]

    I managed to epoxy the pickup pieces together last night. It came out OK. Once I clean it up a bit, it'll be fine.

    As far as my pickup assembly, I just took all the loose parts and glued them together. I didn't get a chance to take many photos photos because it wasn't exactly and orderly process. The dog ears didn't fit as well as they did in the dry run, and one of them was slightly askew. I'll be able to sand it in such a way that it will work, and most of the problem spots will be inside the guitar and won't be visible anyway.

    One thing I'd really like to do is eliminate the process of gluing the blades and coils together. I'm thinking if I put a little groove on those nubs on the sides of my coils, I might be able to make the dog ear serve as a snap-together part and use spacers to set those pieces apart. I don't have the machining capabilities for something that refined, but it's something to think about. I have to really fine tune all the parts so that they all fit together and ensure that they are straight and parallel.

    [​IMG]

    Gluing the baseplate to the bottom of the pickup wasn't bad at all. Everything seemed to survive OK. I could easily make that process easier by making a simple jig to hold the baseplate in place with the rest of the pickup. I attached a photo showing my wire terminals. I have hole behind them where I'm hoping to attach a ground wire. I stuck a piece of copper tape that stretches across the blades.

    Overall, I'm happy enough with this as a prototype for my neodymium sidewinder design. However, I'm torn; there's a lot I would like to do to refine and perfect this design and perhaps make it more of a production piece but I would also like to move on and build a bass and put this pickup in it. In addition, I'm also starting to come up with more pickup designs that I'd like to start working on as well. In conclusion, I'm at a point where I have take a few minutes to relax an do some prioritizing. Refining this design is pretty high on the list, but to a certain degree I'm limited by what I can execute using the limited tools I have at my disposal. I may have to invest in more tools or tooling to take this one to the next step. In the meantime, now that I have a working prototype in my hands, I can get back on track and start cutting some wood.
     
    Last edited: Aug 15, 2017 at 2:46 PM
    Arch Stanton likes this.

  12. pagagigi

    pagagigi TDPRI Member

    Age:
    49
    20
    Sunday
    Italy

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