foam surround repair video?

[unpredictable]

Hi,
Has anyone found any good videos of foam surround repairs on the net that INCLUDE removing the dust cap and inserting a shim? I can't seem to find any...
Thanks

[Ed Holland]

I haven't seen a video, but there are some half decent step-by step guides for example:

http://www.speakerrepair.com/instructions.html

I just did a repair, for the first time, on some 12" woofers, and it's not too hard if you are careful. For shims, I used 3 strips of thin card, carefully selected & folded so they could slide all the way between the coil and magnet, with enough interference just to immobilise the coil firmly when placed evenly around the circumference of the gap.

As for removal of the dust covers, there are two choices. First is to cut the cover itself with a very sharp knife, just inside the glue line, as close as possible. Regluing will create a new glue line that disguises the surgery. The speakers I fixed had a composite cone, and I was able to cut & peel the glue itself, and could have saved the dust caps intact, had they not been battered & creased - I used replacements in the end so that the repair looked nice.

I hope that is helpful,

Cheers,

Ed

[unpredictable]

Thanks but really want that part of the process (removing the dust cap) in video or in very detailed photos. The rest of the process seems fairly straight forward and maybe when I start this will too but I really don't want to hurt the speakers as they are unavailable to replace. My speaker guy told me to try to keep the original dust caps as the weave may be a bit tighter on the replacement. He also stressed to me the importance of using the shims. Anyone else have an opinion on replacing surrounds without removing dust cap? And would still love a good video should anyone know where to find one...

[Ed Holland]

OK, unpredictable I understand your caution to just get stuck in...

From what material are the cones constructed? Paper, polymer, graphite?

That will give a good idea of how delicate the dustcap removal process needs to be, and where you can cut without risk of damage to the cone. What I've seen recommended in most cases is to cut at the point where the cap folds to create a lip for gluing to the cone. If you work carefully with a fine scalpel/craft knife, this keeps the blade parallel to the cone, with no risk of puncturing it. I really don't think there's any "black art" to this part of the job.

The other tip I forgot in the first reply was not to cut the cap all the way around, leave a small "hinge" attached so it will fold back into place after the work is done.

Personally, I wouldn't try the surround replacement without voicecoil shims, there is a danger of misalignment. However, there are some guides that say you dont need to do this, that it's possible to maintain the alignment by feel, and hence they say no removal of the dustcap is needed. That is a matter of personal opinion, and will also be more or less critical depending on the clearance provided for the VC in the gap, which will be different for each design fo speaker.

I did find these other online guides
http://www.decware.com/newsite/refoam.htm
http://www.freewebs.com/crawdaddysspeakers/

Ed

[Ron E]

Originally posted by unpredictable
Anyone else have an opinion on replacing surrounds without removing dust cap? And would still love a good video should anyone know where to find one...

don't do it without shims. The dustcaps in my repair kit were not big enough, so I did this:
I cut carefully with a very sharp razor. the cut is nearly invisible and it is only tacked in a couple places with glue (dark spots)

[unpredictable]

Thanks Ed...Those to guides were both exactly what I was looking for, at least as good as video and nice clear images of what to do with the shims. It describes well in the second guide what my speaker guy was telling me about the particular need in my case to remove dust cap and use shims.

Just for the record the cone is a coated paper one in an older (circa 1990) vifa speaker that is no longer produced. If I get this right I will have picked up a pair of working JPW p1's for 50 Oz dollars ($15 speakers+$35 surrounds) and will be well pleased with myself...

Thanks again for your help Ed...

[Ed Holland]

Happy to help Good luck with the fix!

Cheers,

Ed