Carbon fiber fretless four-stringer

Discussion in 'Luthier's Corner' started by MPU, Dec 4, 2022.

  1. MPU


    Sep 21, 2004
    Valkeala Finland
    After playing with my Status-esque fretless I decided to dive deeper in the world of Status. I’m shamelessly taking the shapes and lines of Status Streamline and make my version of it.


    First I made a plug. I used alder as it’s easy to carve and finish. I brushed two coats of epoxy on the plug. Before taking a mold I sprayed PVA release film over the plug. This pic is after taking the mold and there are loose flakes of PVA film over the plug.


    I took two molds. One for the back and one for the top. I used vinyl ester resin because it does work with epoxy and shrinks less than polyester resin. I wet sanded the mold to 2000 grit and polished it.


    After several coats of mold release wax on the mold it was time for the bass. First coat is clear epoxy-compatible polyerter gelcoat. When that coat had cured I sprayed a light coat of Infutac spray adhesive over the gelcoat. Then I laid the chopped carbon tow over the tacky layer. Here’s what’s left but you can see the size of the cf tow used. I used a full box of this chopped tow. I got a blister on my finger when cutting the tow with scissors.

    9F2BCDD0-3C81-4D2F-A6CD-6DBE2B88197C.jpeg D40AA2C1-3CD2-4C46-AF7F-BCA8F533277B.jpeg

    The last layer after layers of biaxial carbon fiber saturated with epoxy is peel ply. There’s two reasons for peel ply. It makes the surface of the laminate ready for gluing parts without sanding and keeps bleed cloth and vacuum bag from sticking to laminate.


    After laying the bleeder cloth over the laminate the whole package goes to vacuum bag. This is the top mold and laminate.


    Here’s my vacuum pump. A refridgerator compressor with vacuum gauge and vacuum switch.


    Back piece out of mold. The top is curing at the moment. Then it’s time for fitting the back and top together, truss rod channel and center beam. More to come…

    Attached Files:

    Last edited: Dec 4, 2022
  2. MPU


    Sep 21, 2004
    Valkeala Finland
    Resins, gelcoat and carbon fiber are from Easy Composites EU. First impression of the epoxy is that it cures very hard. It has about 1,5h pot life so I had no need to rush while laminating. The cured back has very loud ringing tap tone.
  3. Barticus

    Barticus Supporting Member

    Sep 16, 2017
    That’s cool!
  4. Man, every time I start to feel like I can do something semi successfully along comes @MPU and his cool carbon fiber basses! :laugh: Great stuff, man.
  5. MPU


    Sep 21, 2004
    Valkeala Finland
    Peter Torning and Matt Liebenau like this.
  6. Joshua

    Joshua WJWJr Staff Member Gold Supporting Member

    Aug 23, 2000

    Gary_M and Beej like this.
  7. Subbed. This is interesting! Looks great so far!
  8. svlilioukalani

    svlilioukalani Supporting Member

    Sep 19, 2012
    Seattle, Wa
    Thanks for posting!! Very interesting to see!
  9. Looks great!

    I have wanted to try doing a chopped carbon bass but since I haven't finished my carbon cloth bass yet I haven't given it much thought. I bought a 15,500 foot spool of 3K tow so I've gotta do something with that eventually.
    carsbybigd and mikewalker like this.
  10. Killing Floor

    Killing Floor Supporting Member

    Feb 7, 2020
    Austin, TX
    Nice! Looking forward to watching it come alive.
  11. JazznFunk


    Mar 26, 2000
    Asheville, NC
    As a motorsports fan, and a user of carbon fiber double bass bows, seeing anything done like this with composites is such a cool thing. Can't wait to hear it! Subscribed!
  12. BAG


    May 5, 2014
    New Zealand
    Can't wait to see how this turns out.
  13. rogerbmiller

    rogerbmiller Gold Supporting Member

    Sep 16, 2003
  14. Dirk Diggler

    Dirk Diggler Supporting Member

    Mar 3, 2004
    Anytown USA
    Fantastic work, thanks for sharing the process. Looks like you've got mad skills man.
    AceOfBassFace likes this.
  15. blliB


    Mar 5, 2017
    Way cool!!! I’m in for the ride on this one
  16. andvari7


    Aug 28, 2004
    If I had the coin, I’d be commissioning a carbon fiber bass from you, because this is the coolest thing I’ve seen on this forum in a long time, possibly ever.
    TN WOODMAN likes this.
  17. RichSnyder

    RichSnyder Columbia, MD Supporting Member

    Jun 19, 2003
  18. Barticus

    Barticus Supporting Member

    Sep 16, 2017
    What type structural support are you putting inside of the monocoque?
    e.g.- wood frame in the middle to mount the bridge to?
    Standalone and AceOfBassFace like this.
  19. Get a good pair of electric scissors . Have you tried resin infusion ?
  20. MPU


    Sep 21, 2004
    Valkeala Finland
    No wood except for strap button screws and maybe for bridge screws. You’ll see the support later.