JB Welding your magnets on your old drivers

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Toolfan66
Toolfan66 Posts: 16,895
edited October 2012 in DIY, Mods & Tweaks
Well in my 1C upgrade thread I posted about JB Welding magnets on my drivers. so I thought I would post some pictures as too where I JB Welded my magnets and why.

In the pictures you can see where the first plate has been stamped and used to rivit this plate to the basket. IMO it would take a good jolt to snap this section off so I see no reason to JB weld there.
DriverMagnetshift001.jpg
DriverMagnetshift006.jpg
DriverMagnetshift009.jpg

In this picture you as well as the first pic above you can see where the glue failed to hold the magnet in place.

DriverMagnetshift005.jpg

In this pic you see the back plate, the pin or shaft for the voice coil is what will lock up your driver if you have a magnet shift, you can also see where the glue failed as well. this is the reason why I JB Welded my drivers in the eight places I did.

DriverMagnetshift004.jpg

A final pic to see where I used JB Weld. Now I am not saying you need to use JB Weld, I am sure you could use other good adhesives that are on the market.

SDA1CsJBweld003.jpg

Now just because our drivers are 20+ years of age doesn't mean you will have a magnet shift, for me since they are out might as well add a little insurance since some of these drivers can be hard to find..

Larry.
Post edited by Toolfan66 on
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  • ben62670
    ben62670 Posts: 15,969
    edited March 2010
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    Not all MW's are rivited;) I had my share of bad drivers in my days that died from shipping:(
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • cincycat13
    cincycat13 Posts: 882
    edited March 2010
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    Thanks for posting the pictures...well worth the 1000 words you didn't have to use. I should probably look more into this as I already got 1 replacement driver from ben:)
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  • Toolfan66
    Toolfan66 Posts: 16,895
    edited March 2010
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    ben62670 wrote: »
    Not all MW's are rivited;) I had my share of bad drivers in my days that died from shipping:(

    Correct I should have stated that, Some drivers are not rivited, and then I would suggest putting JB weld in that area..

    If you shine a flashlight in the side of the driver just right, you will be able to tell if it's rivited or not..
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  • WastelandWand'r
    WastelandWand'r Posts: 466
    edited March 2010
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    Tool,
    Hope you dont't mind using your thread but I have a question that i believe is relevant.
    Today while taking my 1C's apart to dynamat the baskets, and mortite the sels, I figured what the hey, I'll lock the magnets into place.
    All was well until the third one when I realized as I went around the magnet the 'ledge' was getting smaller. Closer examniation showed that it had 'slipped'.
    I had not noticed that the driver in question was not working while listening.
    I finished on this, the left speaker, and put everything back together.
    I slowy pushed on the passive and keeping my ear as close as I could to the driver I couldn't hear anything scraping.
    Am I deluding myself that I would hear it, or not? Should you hear it, or if it has slipped are you chasing your tail and replacing it is the only thing you can do?
    All the drivers move, and under power appear to be performing.
    Any thoughts, greatly appreciated.
    Sorry for the rambling.
    Nathan
    Home Rig

    SDA 2.3TL's front and center
    Polk 1000p Center
    Pioneer Elite SC35 Receiver (Pre/Surround
    Sunfire Cinema Grand 5X200-Back in the mix.
    OPPO BDP-93
    Squeezebox
    Stepped up to name brand Speaker Cables and interconnects!
    Monitor 4, 5, 7, 10's, SDA 1B's, 2B's, 2.3TL's, RTA 15TL's all in storage waiting for me.
    Sales Rating #1!!
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  • Toolfan66
    Toolfan66 Posts: 16,895
    edited March 2010
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    WastelandWand'r wrote: »
    Tool,
    Hope you dont't mind using your thread but I have a question that i believe is relevant.
    Today while taking my 1C's apart to dynamat the baskets, and mortite the sels, I figured what the hey, I'll lock the magnets into place.
    All was well until the third one when I realized as I went around the magnet the 'ledge' was getting smaller. Closer examniation showed that it had 'slipped'.
    I had not noticed that the driver in question was not working while listening.
    I finished on this, the left speaker, and put everything back together.
    I slowy pushed on the passive and keeping my ear as close as I could to the driver I couldn't hear anything scraping.
    Am I deluding myself that I would hear it, or not? Should you hear it, or if it has slipped are you chasing your tail and replacing it is the only thing you can do?
    All the drivers move, and under power appear to be performing.
    Any thoughts, greatly appreciated.
    Sorry for the rambling.
    Nathan


    If your driver is moving in and out normal, with no scraping scratching sound you are "OK", not all the magnets were assembled dead center. in the pics above you see the back plate with the pin that is about 3/4" of an inch, that is the part that is critical to be centered with the driver for the voice coil. I found a few of my drivers the same as yours so no worries.

    Hope this helps,

    Larry.
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  • WastelandWand'r
    WastelandWand'r Posts: 466
    edited March 2010
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    To the best of my hearing they are scratch free. Hopefully with the application of adhesive they are set.
    Thanks again,
    Nathan
    Home Rig

    SDA 2.3TL's front and center
    Polk 1000p Center
    Pioneer Elite SC35 Receiver (Pre/Surround
    Sunfire Cinema Grand 5X200-Back in the mix.
    OPPO BDP-93
    Squeezebox
    Stepped up to name brand Speaker Cables and interconnects!
    Monitor 4, 5, 7, 10's, SDA 1B's, 2B's, 2.3TL's, RTA 15TL's all in storage waiting for me.
    Sales Rating #1!!
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  • thejck
    thejck Posts: 849
    edited September 2010
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    OK so once again Larry's pics help clear up a lot of understanding. Just to make sure I get it right.
    If you see rivets between the bottom plate and the basket then you should jb weld the magnet to the top plate and the bottom plate in 4 places all around the driver for a total of 8 welds?
    If you are not sure about the rivets in the bottom then do 4 more spot welds between the bottom plate and the basket
    Did I get it right?
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  • Toolfan66
    Toolfan66 Posts: 16,895
    edited September 2010
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    Correct!!!
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  • thejck
    thejck Posts: 849
    edited September 2010
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    Thanks once again Larry
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  • 1996BlackBauer
    1996BlackBauer Posts: 17
    edited October 2012
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    Sorry to bring up an old thread, but it seems that you reconed the woofers, is that necessary? because I have 2 woofers that are locked, but still have impedance. how difficult would it be to realign the woofers with all the soft parts in them? also if the magnet has not fallen off, how hard would it be to get it off? I do realize I can get replacement woofers, but JB Weld is much cheaper then new woofers.
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  • pitdogg2
    pitdogg2 Posts: 24,554
    edited October 2012
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    1996BlackBauer wrote: »
    Sorry to bring up an old thread, but it seems that you reconed the woofers, is that necessary? because I have 2 woofers that are locked, but still have impedance. how difficult would it be to realign the woofers with all the soft parts in them? also if the magnet has not fallen off, how hard would it be to get it off? I do realize I can get replacement woofers, but JB Weld is much cheaper then new woofers.

    No Larry took a bad MW apart to illustrate the merit of JB weld and to show where the glue is applied.
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  • dscheer
    dscheer Posts: 47
    edited October 2012
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    As always great info post Larry...My RTA 12Cs are 28 years old (I purchased them 1984) I think I will JB weld all the Cone Drivers. Still need to rebuild the crossovers. I learn so much from this forum. Thanks!
    Donto's System:
    Parasound HCA3500
    Parasound HCA 1500a (4 each)
    DIY Set Tube Amps (4 each)
    Parasound 850 Pre-Amp
    Onkyo CD Player
    Teac Tape Play/Recorder
    Samsung 50" TV
    Toshiba HD DVD Play/Recorder
    Polk RTA12C Speakers
    DIY 15" Side-Firing Subwoofers (2 ea)
    DIY 15" Down-Firing Subwoofer
    Adcom Power Conditioner
    DIY Isolation Transformers/Power Conditioner
    4 ea 20 Amp Power Circuits
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  • dscheer
    dscheer Posts: 47
    edited October 2012
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    Sorry for the double post, my computer froze up.
    Donto's System:
    Parasound HCA3500
    Parasound HCA 1500a (4 each)
    DIY Set Tube Amps (4 each)
    Parasound 850 Pre-Amp
    Onkyo CD Player
    Teac Tape Play/Recorder
    Samsung 50" TV
    Toshiba HD DVD Play/Recorder
    Polk RTA12C Speakers
    DIY 15" Side-Firing Subwoofers (2 ea)
    DIY 15" Down-Firing Subwoofer
    Adcom Power Conditioner
    DIY Isolation Transformers/Power Conditioner
    4 ea 20 Amp Power Circuits
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  • tat
    tat Posts: 159
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    What is that material i see glued to the frame/spokes etc. It looks like back of insulation with branding. Second time Ive seen it here at club.
    When freedom is outlawed, only outlaws are free...
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  • lightman1
    lightman1 Posts: 10,776
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    tat wrote: »
    What is that material i see glued to the frame/spokes etc. It looks like back of insulation with branding. Second time Ive seen it here at club.

    Dynamat or any other adhesive sound deadening material. It keeps the metal baskets from vibtating and producing a "ringing" effect. Highly recommended during your bout with upgraditis.
    Not curable but treatable.
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