Got some Pioneer HPM-900's need cone repair

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I just got a pair of Pioneer HM-900 Speakers, one cone has a crack, My intent is to fix it. Does anyone know of a good method to fix a crack in these cones, I believe they are graphite based, and pretty fragile. If not, I have my own Idea, but I would need a piece of "donor" material from an already unrepairable Hpm 900 cone. Anyone have any suggestions, or have a dead cone to sell or donate?

I know I can get HPM 100 drivers, but I want to try to keep them stock.

Jon
 
Dear Jon,
I have very valuable experience in repairing cracked cone. I hope your HPM900 should be of paper cone where the dack grey colour is a type of dye giving you the impression this driver is of graphite.
Essentially speaking I have a type of paper that is very useful to repair paper cone. It is very cheap. For the cost of few USD I could get a piece of this paper of size like 2feet x 2feet. I can actually repair 10 cracked cone easily without running short of this material.
I am residing in Malaysia, so, is it a problem to send this to you? I am not very sure.
I have personnally done quite a lot of repair for close friends with this paper. Untill we find a way to send to you then I shall explain in detials the method of repair.
Beside this paper, I would also send you together the glue and a small brush required for this purpose.
I would certainly advise you not to throw away your stock cone. Repairing it would be close to original, as this paper capable to withstand the vibration of a Woofer in particular, and still stay intact, if you have done properly.
You may reach me at: datumx.eng@gmail.com

Best regards

from
chewkwokhon
 
I know it's an old topic, but who knows, maybe you still need help. Yes those ARE graphite cones, and yes, if the cracks are not the length of the cone or not hideously severe, you can fix them.
Use the cheap super glue. When i say cheap, I mean the 99 cent liquid, and not a gel type. It turns out that Cyanoacrylate is very similar to whatever they used to bond the graphite originally, and makes for a permanent repair. Carefully(CAREFULLY!!) work it into the crack. Make sure you get it to the end of the crack, even if it's just a top coating. DON"T stress the cone when doing this. You can sprinkle dry graphite available as lubricant from a hardware store, and sprinkle it into the crack before the glue drys. Wait for it to dry, and then use some fine emery cloth to sand off the excess. It has a good chance of playing like new, and will look decent too. I use a little WD40 on a soft cloth to buff the cone afterwards. That will blend in the repair, and restore the original luster.
If it wasn't too bad to start with, and you were careful, and lucky too, then they'll be as good as new.
 
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