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Refoaming Bass Driver

Discussion in 'DIY Projects' started by Rope, Nov 1, 2010.

  1. Rope

    Rope Well-Known Member Famous

    I'm about to embark refoaming two Bose 301, 8" mid/bass drivers. Any advice before commencing with the process?

    I'm prepared to take my time, and I do have text destructions. I'll post pricks (daaayum, sounded like Brett Favre) as I proceed with the festivities.

    Rope
     
  2. DIYer

    DIYer Well-Known Member Famous

    You use Bose speakers? [​IMG]
     
  3. soundhound

    soundhound Well-Known Member

    Just follow the directions to the letter and don't hurry. Expect that it will be a messy process. You will need some single edge razor blades.
     
  4. Rope

    Rope Well-Known Member Famous

    Of course, traded PMC OB1's straight across, well I threw in some boot, for some series 1 Bose 301's. :teasing-tease:

    These belong to my mother, she thinks they're the pure shit. And I will admit, for her kind of listening and the amount, they do the job quite well. They've got to be 30 years or older.

    Rope
     
  5. Rope

    Rope Well-Known Member Famous

    Thanks. I'll indeed take my time and I have plenty of single edge razor blades, Zacto to be more precise.

    Rope
     
  6. soundhound

    soundhound Well-Known Member

    By Zacto, do you mean an X-acto knife? If so, that won't be of much use. You need single edge razor blades to both cut the old foam away from the cone, and to scrape the old glue / foam from the cone and basket.
     
  7. Rope

    Rope Well-Known Member Famous

    First installment, basket and cone approximately 75% cleaned up. Before bed time I'm going to apply a product to the basket called Kleen Strip. It's used to prep cars for paint by stripping through paint and primer to metal.

    Rope
     

    Attached Files:

  8. Rope

    Rope Well-Known Member Famous

    Yup, you're correct, didn't work worth a shit! I used a really sharp pocket knife held at 90 degrees to the cone to scrape off the old foam, and a dull pocket knife to scrape the glue off the basket.

    Rope
     
  9. soundhound

    soundhound Well-Known Member

    Yeah, well....for the benefit of those who will doing this in the future, I used to be a certified a JBL speaker technician and did this procedure a lot...we all used razor blades for scraping the old foam and glue off (trust me on this one - they work best). I also would not use any chemical on the frame or cone, as this can either cause unintentional damage, or its residue could interfere with the final glue.
     
  10. Rope

    Rope Well-Known Member Famous

    I did use chemical on the metal basket, after it sat all night, wiped it off, cleaner than a babies bottom. Next I'll wipe it down with isopropyl alcohol, hit it with my dremel tiny wire brush and then a tack cloth.

    I didn't and would never use chemical on the cone material, since it would absorb any chemical and would not hold glue.

    Again, thanks for the pointers!

    Rope
     
  11. soundhound

    soundhound Well-Known Member

    Yeah, for this procedure, I would not recommend trying to reinvent the wheel on someone's expensive speaker driver. I still would warn against using any chemical on the speaker basket. Scraping the Bostick glue used to bond the parts should be done with a razor blade to avoid any contamination....keep wet chemicals away...far away.
     
  12. Rope

    Rope Well-Known Member Famous

    Got it! I have one more driver to refoam, I'll use strickly razor blades and hope the first holds glue.

    Rope
     
  13. soundhound

    soundhound Well-Known Member

    Keeping wet stuff away is also to avoid any accidents with it splashing onto the cone which would immediately absorb it if it is felted paper, or possibly melt it if it is plastic.
     
  14. Rope

    Rope Well-Known Member Famous

    SH -

    Is there truly a need to cut the dust cap and align the voice coil before installing the foam surround?

    Rope
     
  15. soundhound

    soundhound Well-Known Member


    Absolutely do not do that!!! The spider holds the voice coil and cone concentric to the pole piece; there is nothing you can do by cutting the dust cap off except allow dust or other debris to enter the magnetic assembly, and in any event you can't align the voice coil by cutting the dust cap off. Aligning the voice coil in the gap requires cutting the spider away from the frame, which usually destroys it, meaning that a new cone kit would be required. Shims of the proper thickness are used to align the voice coil.

    Don't even think of going there.....
     
  16. Rope

    Rope Well-Known Member Famous

    The reason I ask is, the distructions go there and I see no reason to perform those steps. Better to ask than be sorry.

    Thanks again!

    Rope
     
  17. soundhound

    soundhound Well-Known Member

    The only possible instance where taking the dust cover off might accomplish something is if the refoaming manufacturer included shims to center the voice coil while the glue dries. However, as I mentioned earlier, the centering is determined by the spider, so even if you shimmed the voice coil, all that would do is perhaps give more insurance that the cone is straight while the glue dries.

    As long as you make sure the cone is not canted one way or the other as the glue dries, everything will be OK (I've never had a problem with the cone staying straight).
     
  18. Rope

    Rope Well-Known Member Famous

    Anyone want to purchase two Bose dust covers filled with patented SH piss...$800.00 each. :eek:bscene-birdiedoublered:

    Rope
     
  19. Rope

    Rope Well-Known Member Famous

    Finished glueing the new foam to the cone, after letting it dry all night, I'll glue the foam to the basket and reinstall the gasket, let that dry for 24 hours. I'll start disassembling and cleaning up the second woofer tomorrow night. Hopefully I'll finish by Thursday.

    Rope
     
  20. Rope

    Rope Well-Known Member Famous

    One Finished Product:

    Rope
     

    Attached Files:

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