Is JB Weld is the only thing available for preventing magnet shift?

MysteryMystery Posts: 2,543
edited January 15 in Vintage Speakers
Recently, I'm cleaning (well, trying to) my basement as I had lot of free time.
I had couple of monitor 4's, 4.5's etc... tucked in the corner in basement.
I remembered all of them were working when I stored them few years ago.
Now, two of them woofers have the stupid dreaded magnet shift and makes tweeter like sound with no movement.
So pissed off! What a waste! Hope Polk is using better glue on their newer models.
Anywho, now I need to keep others from the same fate.
Is JB Weld the only thing? If yes, which type of JB weld is good for magnets?
This cold-weld steel reinforced?
https://www.amazon.com/J-B-Weld-8265S-Cold-Weld-Reinforced/dp/B0006O1ICE/
or Kwik-weld?
https://www.amazon.com/J-B-Weld-8276-KwikWeld-Reinforced/dp/B0006O1ICY/
or Steelstick putty?
https://www.amazon.com/J-B-Weld-8267-S-SteelStik-Reinforced/dp/B000786GLM/
...
What about two part epoxy or metal epoxy that Harbor Freight sells?
Any other recommendation?

Sonus Faber Concerto Grand Piano, Klipsch, B&W DM602.5, Epicure 20+, T/E 280, 100V, Polk.
Subwoofers: Monitor Audio, B&W ASW300, Triad ProSub Bronze.
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Comments

  • JazzheadJazzhead Posts: 159
    I used PC-7 epoxy. It's thick enough (at room temperature) that you can blade it on without mess/sagging. It's bombproof once it cures.
    Polk Audio original RTA-12s w/ 12 inch Polk Stands; DHS Speaker Service upgraded crossovers w/ Sonicap/Mills; comb filtering mod (hyperdamped outer drivers/mirror imaged); tweeter diffraction mod; Cardas silver-rhodium binding posts; Neotech UPOCC internal wire; Sonic Barrier 3-layer; Dynamat Xtreme
    Ayre K-5xeMP preamplifier
    Cambridge Audio 840C CD player; Herbie's Audio Lab Super Black Hole CD Mat
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    Furez 10/2 speaker cable & connectors, shotgunned
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    Herbie's Audio Lab system isolation: Tenderfeet, Big Fat Dots, Grungebuster Dots, Little Fat Gliders
    Dedicated 20A/10 AWG circuit; Furutech GTX-D (G) outlet; Furutech eTP80; Shunyata Research Venom Defender; Synergistic Research Orange fuses
  • GardenstaterGardenstater Posts: 1,854
    edited January 15
    I used this stuff and would use it again. It adheres tenaciously to metal and ceramic/glass and I like that it is clear. One drawback is it only seems to come in the large tube. I squeezed (squoze?) it into a syringe to make it easier to apply, especially to back edge of magnet. Doesn't shrink a lot but does some, through solvent evaporation.

    There's so many suitable choices!

    nvrg84akbret.png
    George / NJ

    Polk 7B main speakers, most mods comp. (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • MysteryMystery Posts: 2,543
    edited January 15
    But how do you know if that prevented magnet shift?
    Some drivers never shift whether you epoxy glue or not.
    Did anyone test after applying epoxy by dropping or shaking the speakers or something in that manner?
    Or is it just a trust on whatever glue you chose?

    Sonus Faber Concerto Grand Piano, Klipsch, B&W DM602.5, Epicure 20+, T/E 280, 100V, Polk.
    Subwoofers: Monitor Audio, B&W ASW300, Triad ProSub Bronze.
  • VR3VR3 Posts: 24,283
    Not sure I would recommend shaking or dropping speakers, ask @treitz3
    - Not Tom

    "No, that's silly talk. Dude, you can't possibly be this audio dumb so quit the act." - Doro
  • MysteryMystery Posts: 2,543
    edited January 15
    VR3 wrote: »
    Not sure I would recommend shaking or dropping speakers, ask @treitz3

    I know. What I was saying was for test purposes if anyone did a test with any drivers using different glues to confirm if they prevent magnet shift or not.
    Doesn't make sense to drop the one you just put epoxy on from a nice speaker.
    This issue came like 15-20 years ago and just wondering if anyone tested glue/epoxy properly or not with test speakers.
    Even someone who put certain epoxy and had a bad drop or accident that pretty much guaranteed magnet shift but didn't also would help.

    Sonus Faber Concerto Grand Piano, Klipsch, B&W DM602.5, Epicure 20+, T/E 280, 100V, Polk.
    Subwoofers: Monitor Audio, B&W ASW300, Triad ProSub Bronze.
  • pitdogg2pitdogg2 Posts: 18,281
    edited January 15
    One thing is for sure, if you do not use it you can come home to a shifted magnet having never dropped or bumped. All this is doing is helping whatever adhesive is left under the magnet to not allow it to shift to the best of our ability. It will be much harder for the magnet to shift if it must jump this barrier we put around the magnet. Can it still shift if it's dropped sure it can.
  • MysteryMystery Posts: 2,543
    pitdogg2 wrote: »
    One thing is for sure, if you do not use it you can come home to a shifted magnet having never dropped or bumped. All this is doing is helping whatever adhesive is left under the magnet to not allow it to shift to the best of our ability. It will be much harder for the magnet to shift if it must jump this barrier we put around the magnet. Can it still shift if it's dropped sure it can.

    Okay so there is no official or non official test done.
    I think around 10 years or so ago I did apply two part epoxy on few Polk drivers but those speakers are long sold.

    But looking at the recent magnet shift on the speakers, I'd epoxy any vintage Polk I run into.
    In conclusion, put something, doesn't matter what, as long as it's epoxy or metal weld to help prevent magnet shift and cross fingers.

    Sonus Faber Concerto Grand Piano, Klipsch, B&W DM602.5, Epicure 20+, T/E 280, 100V, Polk.
    Subwoofers: Monitor Audio, B&W ASW300, Triad ProSub Bronze.
  • MysteryMystery Posts: 2,543
    pitdogg2 wrote: »
    Hmm... That's much cheaper than the epoxy.
    Does this work as good as JB Weld for metal like magnets?

    Sonus Faber Concerto Grand Piano, Klipsch, B&W DM602.5, Epicure 20+, T/E 280, 100V, Polk.
    Subwoofers: Monitor Audio, B&W ASW300, Triad ProSub Bronze.
  • pitdogg2pitdogg2 Posts: 18,281
    edited January 15
    I feel it works better it's much easier to get in the magnet spaces you can build it up easier it doesn't run. You just caulk a big bead around your magnets and then you smooth out with your finger press it in and smooth it down and it it locks everything in place. it's well regarded here a lot of us have started using it I did JB weld on my first ones I'll never use it again.
    a8c8g0ax0044.jpg
    v2j72ro4jnw7.jpg

  • MysteryMystery Posts: 2,543
    pitdogg2 wrote: »
    I feel it works better it's much easier to get in the magnet spaces you can build it up easier it doesn't run. You just caulk a big bead around your magnets and then you smooth out with your finger press it in and smooth it down and it it locks everything in place. it's well regarded here a lot of us have started using it I did JB weld on my first ones I'll never use it again.

    Okay, I just read the description and it does mention metal but says at least one of the surfaces must be porous.
    Is Polk magnet or frame porous?

    Sonus Faber Concerto Grand Piano, Klipsch, B&W DM602.5, Epicure 20+, T/E 280, 100V, Polk.
    Subwoofers: Monitor Audio, B&W ASW300, Triad ProSub Bronze.
  • pitdogg2pitdogg2 Posts: 18,281
    Do a search we've been over this time and time again. It works and holds or you can keep going over and over it in your head forever.
  • xschopxschop Posts: 2,071
    I use Power Grab in the hand tube. I've even had to glue SL5000 tweeter magnets with good results.
  • MysteryMystery Posts: 2,543
    edited January 16
    lawdogg wrote: »
    Mystery wrote: »
    Okay so there is no official or non official test done.
    I think around 10 years or so ago I did apply two part epoxy on few Polk drivers but those speakers are long sold.

    But looking at the recent magnet shift on the speakers, I'd epoxy any vintage Polk I run into.
    In conclusion, put something, doesn't matter what, as long as it's epoxy or metal weld to help prevent magnet shift and cross fingers.

    I did my own destructive testing (throwing them on the concrete garage floor) and found Loctite power grab shifted very easily. I've only used epoxy ever since and epoxy has never shifted.

    kfxdmqsyu2ne.jpg

    Yes thanks.
    I'm leaning towards epoxy but thinking if Loctite PL Max is better.
    It mentions metal and stainless steel.
    I have about a dozen and I think 3 of them are frozen. :(

    https://www.loctiteproducts.com/en/products/build/construction-adhesives/loctite_pl_premiummaxconstructionadhesive.html

    Sonus Faber Concerto Grand Piano, Klipsch, B&W DM602.5, Epicure 20+, T/E 280, 100V, Polk.
    Subwoofers: Monitor Audio, B&W ASW300, Triad ProSub Bronze.
  • lawdogglawdogg Posts: 391
    edited January 16
    Good luck and enjoy the process! I'm sure you'll be able to get it done!
    <3 my 3.1TLs

    I will fix your shifted magnets for free. :)
  • VSAT88VSAT88 Posts: 915
    I used nothing at all early on and ...Magnets shifted.
  • MysteryMystery Posts: 2,543
    VSAT88 wrote: »
    I used nothing at all early on and ...Magnets shifted.

    Of course that's why the thread is here.
    Question is about what to use among many choices.

    Sonus Faber Concerto Grand Piano, Klipsch, B&W DM602.5, Epicure 20+, T/E 280, 100V, Polk.
    Subwoofers: Monitor Audio, B&W ASW300, Triad ProSub Bronze.
  • GardenstaterGardenstater Posts: 1,854
    I think if one didn't want to use epoxy or what I suggested above for whatever reason (mess, don't have any handy etc), one could use this prior to filleting in with some other adhesive as a 2nd insurance at a later time:

    21vyehcyfnp1.png
    George / NJ

    Polk 7B main speakers, most mods comp. (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • audioluvraudioluvr Posts: 3,186
    edited January 17
    Polyurethane isn't really that strong IMHO. You want something that bonds/ welds everything together. I would test it by placing two pieces of scrap metal together then running a bead around the perimeter. Once cured try to get the two pieces to move
    Cambridge Audio 851N Streamer/DAC
    Belles 21A Pre modded with Mundorf Supreme caps
    B&K M200 Sonata monoblocks refreshed and upgraded
    Belles 350A Reference modded with Mundorf Supreme caps
    Polk SDA 1C's modded
    Wireworld Silver Eclipse IC's and speaker cables


    There is about a 5% genetic difference between apes and men …but that difference is the difference between throwing your own poo when you are annoyed …and Einstein, Shakespeare and Miss January.

    by Dr. Sardonicus
  • GardenstaterGardenstater Posts: 1,854
    The one I last brought up is a type of super glue (cyanoacrylate). The one Mystery was speculating about is a Silane (SiH4) Modified Polymer, which combines the highly elastic properties of Silicone with high mechanical strength of Polyurethane. Not sure I would want to use anything that is elastic where you want to protect from dislodgement due to impact.
    George / NJ

    Polk 7B main speakers, most mods comp. (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • I recently used Loctite Instant Mix epoxy to do the magnets on my 2B's. It was readily available and I found it easy to apply cleanly. I used maybe half of the 14ml tube to do 4 magnets, so I would expect you could get 8 to 10 out of it. That was also applying a full bead all the way around the magnets, which in hindsight was probably overkill.
    mm8ka1pvz49j.png
  • only the one side of magnet is epoxied, correct? I saw the pic here of one done that had glue on both sides of the magnet. That look to be very tough to do without making a huge mess.
  • GardenstaterGardenstater Posts: 1,854
    edited January 18
    Both sides, without a doubt. You can do one side, let it cure a bit, then flip the speaker over and do the other side, so gravity works for you instead of against you.


    bigmontana - I'm glad you chimed in because I think that stuff may be ideal and I forgot who had posted it before.

    https://www.ebay.com/p/536442390
    George / NJ

    Polk 7B main speakers, most mods comp. (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Crown D150 amp
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • The static mixer that comes with the Instant Mix epoxy makes it easy to get to the bottom side of the magnet.
    7hl4ryw5khql.jpg

    You do have to work somewhat quickly or the epoxy will start to thicken inside the mixer. Don't stop for a break until you're completely done!
    I did the top side of all four magnets and then immediately did the bottom sides starting with the first one again. No issues with dripping or slumping.

    I was able to find it at my local Target: https://www.target.com/p/loctite-47-fl-oz-epoxy-5-min-instant-mix/-/A-14767197#lnk=sametab
  • very helpful! Thank you
  • drumminmandrumminman Posts: 3,402
    I used JB Weld original formula for all the mw’s in my 2.3tl’s, RTA-12c’s and CRS+’s and had no issues. It takes a while to dry, but it will not fail.
    I had a good supply of nitrile gloves and paper towels on hand to immediately remove any excess.
    "Science is suppose to explain observations not dismiss them as impossible" - Norm on AA; 2.3TL's w/sonicaps/mills/jantzen inductors, Gimpod's boards, Lg Solen SDA inductors, RD-0198's, MW's dynamatted, Armaflex speaker gaskets, H-nuts, brass spikes, Cardas CCGR BP's, upgraded IC Cable, Black Hole Damping Sheet strips, interior of cabinets sealed with Loctite Power Grab, AI-1 interface with 1000VA A-L transformer
  • TennManTennMan Posts: 1,122
    I used JB Weld. I have no doubt about it's strength but it was messy to apply. If I had it to do again I would use clear two part epoxy.
    SDA 2BTL · Sonicaps · Mills resistors · RDO-198s · New gaskets · H-nuts · Erse inductors · BH5 · Dynamat · Crossover upgrades by westmassguy
    Marantz 1504 AVR (front speaker pre-outs to Adcom 555)
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    SDA CRS+ · Hidden away in the closet
  • MysteryMystery Posts: 2,543
    Okay I went back to what I used 8 years ago, two part epoxy.
    It hardens like rock and when it is applied at multiple places, even if it's not adhesive like original glue, it'll block movement.

    Sonus Faber Concerto Grand Piano, Klipsch, B&W DM602.5, Epicure 20+, T/E 280, 100V, Polk.
    Subwoofers: Monitor Audio, B&W ASW300, Triad ProSub Bronze.
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