E130-8 --- What glue to use to re-glue top plate after being dropped?

[Mazza]

Dear all,
I have a single E130-8 that has been dropped. The consequences were catastrophic as can be seen here (http://www.audioheritage.org/vbulletin/showthread.php?43070-JBL-2202A-with-15-quot-basket!-what-to-re-cone-as&p=438643&viewfull=1#post438643).

Today I realised that the top plate has slipped and managed to part it from the magnet....


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Happily I have a hole saw that is a perfect fit for the pole and top plate that will be a great shim....


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So what glue to use? I assume an epoxy would be best? :confused:


Any and all help appreciated :D


Cheers!

[RMC]

Hi Mazza,

RE "Any and all help appreciated."

To bond metals in general i've had good results using the glue on pic. But you must do as indicated, like a clean parts surface, etc.

The polyurethane glue requires some humidity to cure, so spray a fine mist of water on one side and put the glue on the other, then clamp together.

The glue makes foam while curing (it expands, filling tiny holes if any). People often try to wipe it off while its wet = mistake, gets messy. You let it dry and when excess foam is rigid you simply cut-off the excess with a knife or exacto. Simpler.

Enlarge the pics to read description and instructions they're clear enough to do so. Sorry for the light reflection on the first picture, right where it says metals.

READ AND FOLLOW THE LABEL.

Richard

898568985789858

[Mazza]

Hi RMC,
Many thanks for your input. Much appreciated.

I have used these glues for timber and they are very good indeed.

I do worry that the foaming action might invade the gap area and create a problem.

The top plate is held extremely strongly against the magnet - no clamping will be necessary.

In fact the strength of the attraction had me worried I'd loose my fingertips its that strong that I used the large screw drivers to give my fingers some safe working space - its a bit scary just how strong this magnet is!

Any glue going between the top plate and magnet is going to be very well squeezed out and this, combined with the foaming action of the polyurethane glue I worry will be a problem for the gap. :dont-know:

[RMC]

Based on precaution principle regarding foaming and gap (a legitimate concern) you might be better looking for something else. Can't win them all...

[Earl K]

Mazza,

I would simply follow GordonW's lead and use 30 minute, 2-part Epoxy for that magnet repair.

GordonW over at AudioKArma (https://www.audiokarma.org/forums/index.php?threads/looking-for-help-with-magnet-shift.956723/#post-14718406)

I'm thinking that you might also want to put a thin coating of petroleum jelly on that gap spacer ( just so it doesn't get glued in place ).

:)

[Mazza]

Wow, nice one EarlK! Perfectly on topic and recent too.

Thank you 😁🍻

[edgewound]

The best adhesive to use is an elastomer modified cyanoacrylate with accelerator. Adhesive on the magnet, accelerator on the top plate. Lube the gap surfaces with a silicone grease or Krytox grease.

Bob Smith Industries "Maxi-Cure" and "Insta-Set" is an excellent choice. Available from Amazon or possibly your local hobby store.

Make sure you scrape the mating surfaces clean of adhesive residue and clean thoroughly with acetone.

[Mazza]

Many thanks Edgewound, really appreciate your professional input - very generous of you thank you! :hurray:

One question - is the top plate and pole coated in a clear rust preventative?

I did wonder if I were to damage a protective coating (if any) there would be potential for the top plate and/or pole to rust?

:dont-know:

[edgewound]

Many thanks Edgewound, really appreciate your professional input - very generous of you thank you! :hurray:

One question - is the top plate and pole coated in a clear rust preventative?

I did wonder if I were to damage a protective coating (if any) there would be potential for the top plate and/or pole to rust?

:dont-know:

No clear coat, just plated.

I would be concerned with the teeth of the hole saw leaving burrs on either side of the gap.

That's why I use mylar shim stock built up to .057". Won't damage the metal at all.

[Mazza]

Yes I agree about the saw burring the pole. I hammered the teeth out from the inside to keep them from damaging the it.

Thank you for answering my question. Very generous of you to share your professional expertise and time.

:applaud: