My kind of man, shimming is it, then you know where you are, without shimming it will allways be guess work, and you get a chance to clean and check  under the dustcap. Good pics

My concern about the shim method is that you leave the voice coil fully exposed during the time the dust cap is off. Whenever I tried this, I worried I would have something fall in, no mater how clean I kept the area I was working in. I liked the idea of keeping the dust cap intact and letting electo-magnetism do the work for me.

You only need to remove the dustcaps & shim to glue down the outer edges of the new foam rings, the rest of the work can & should be done prior to this. Leave them in place until you do this to save them being exposed for any length of time.

Chris.

I am refoaming three CX100s this week. I really had a tough time getting the old adhesive off the frames. The cones were not too hard to clean off this time. Now I'm at the point of deciding to use the battery method or to shim? It seems to me the spiders help hold the voice coils in place and there is not enough movement to the cone to throw it off, so a battery may be all that's needed. Any opinions?

What happens to the surround using a battery you can see on this drawing, a 5 Mm pull will allso pull the outer edge of the surround away from its natural rest position by +-5 Mm

 

 

That makes sense. I guess I've just been lucky up until now, however I have used shims on larger diameter speakers in the past. I should always use shims to be safe.

Dillen:

2. If white glue is what we in Denmark call woodworkers glue, it will be
nothing but trouble and I simply cannot see how anyone can recommend it.
It hardens completely, becomes brittle and will not bind to the metal basket.

I have refoamed a couple of CX 100's and used the white glue from Good HiFi. This glue looks, smels and feels like ordinary woodworkers glue, but maybe it is not. I'm not a chemist. I would like to find a suitable glue in Denmark to reduce the shipping costs.

Dillen:

Speaker cement is very easy to work with, it settles reasonably well within
10 hours and completely within about 24 hours or so.
It has an incredibly strong bond to almost any material and remains just
slightly flexible and elastic

Can I buy the speaker cement that you mention in Denmark? If so under what name?

/riis

 

This drawing does not apply, since the surround is slightly above the frame in rest and isn't pulled very hard against the frame when connecting the battery. There is no chance that the position could change as much as 5 mm. If you had said 0.5 mm, then I could agree.
I have now done a pair of CX100 and a pair of CX50 with the battery method. All six drivers still work perfectly.

Agent00soul:

This drawing does not apply, since the surround is slightly above the frame in rest and isn't pulled very hard against the frame when connecting the battery. There is no chance that the position could change as much as 5 mm. If you had said 0.5 mm, then I could agree.
I have now done a pair of CX100 and a pair of CX50 with the battery method. All six drivers still work perfectly.

Take a 0.5 Mm wire and then a 5 Mm and look at it, then maybe you will learn what the difference between 0.5 and 5 Mm is.

Just measured a 8" driver with an old 1.5 V cell, the cell i checked before testing, it showed 1.22 V, I got a pull of 3.4 Mm, and that with an old battery taken from an emergency flashlight, where it has been for about a year. What happens with a fresh battery with 1.6 V ?? you tell me.

The measurement was done on a 8" Beovox 3702 bass driver with new surround, without surround the pull will be a little longer.