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105/3 -B160(SP1257)- Adhesive recommendation/repair advice?

 
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sydbar81
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Joined: 12 Apr 2018
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PostPosted: Mon Oct 08, 2018 2:15 am    Post subject: 105/3 -B160(SP1257)- Adhesive recommendation/repair advice? Reply with quote

Seeking some professional advice on a proper repair. I just came in to possession of a 105/3 set (sort of a 'barn find' have been in storage for over 10 years) and the surround is separating from the cone in two areas on one of the drivers.

Is a touch up possible or does this need a full rework?

Also, is there an adhesive that can be recommended?

Links to photos below.


https://imgur.com/a/LPU07Du
https://imgur.com/a/mpwcOJj
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speakerguru
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Joined: 18 Nov 2005
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Location: Green Hut, Tovil

PostPosted: Mon Oct 08, 2018 10:17 pm    Post subject: Reply with quote

Assuming the voice coils are not rubbing, then re-sticking locally should be OK.

See http://www.hifiloudspeakers.info/speakertalk/viewtopic.php?t=1655 for some info on the original adhesive, which was Bostik 4141, but you'll have to do your own research to find a modern equivalent. Heat bonding is also possible but risky without jigs and tricky on assembled units.
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sydbar81
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PostPosted: Tue Oct 09, 2018 7:10 pm    Post subject: Reply with quote

Thanks, hard to find any info on the 4141 other than it was an 'aqueous emulsion' type used for bonding upvc.

I'm assuming a pva should be ok and will not melt anything.

No rub on the voice coil, just a hilarious squeak like a dog toy from the air pushing through the split.
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speakerguru
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PostPosted: Tue Oct 09, 2018 10:18 pm    Post subject: Reply with quote

sydbar81 wrote:
...I'm assuming a pva should be ok and will not melt anything...


"pva" doesn't narrow it down a lot. There are so many variations. Most white "PVA" wood glues would not work on plastic.

I seem to remember using something like this https://www.ebay.co.uk/itm/382118790887 when I replaced the foam surrounds and doughnuts on my 103|4s a couple of years ago.
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sydbar81
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PostPosted: Fri Oct 12, 2018 7:59 am    Post subject: Reply with quote

Thank you for taking the time to answer my questions.

I was able to repair the driver based on your recommendation. I pulled the driver out and used a syringe to apply glue from the back side. Seems to be holding just fine. I reinstalled the driver with a new gasket and it is air tight again. Can't even tell it has been repaired.

I have yet to test since since these are still being restored. Can't wait to hear them sing. Drove from Portland, Oregon to Los Angeles, California 30 hours round trip to pick these up.
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speakerguru
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PostPosted: Fri Oct 12, 2018 1:35 pm    Post subject: Reply with quote

Glad you managed to effect a repair. Very Happy
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