I feel the need to add my own comments here. Experience has taught me that whenever possible you should ALWAYS shim when refoaming drivers. It is the ONLY way to guarantee correct coil centering & height of the cone when attaching the surround. I use strips of acetate sheet.

OK - there may be certain drivers where this isn't possible but this should be the exception & not the rule.

As for the type of adhesive - I used some so called "special glue" from a supplier of foam surrounds. The foam surrounds started peeling away after a couple of weeks. I should have known better when I was applying it as it was very simlilar to PVA (it probably WAS PVA) but decided to give it a try. I now use only correct speaker cement.

Martin isn't in the "don't try this at home camp" at all, he simply thinks the same as myself. If you aren't 100% confident in what you are doing & choose to ignore well established & proven methods then you shouldn't be doing it! I too have had many botched attempts at refoaming land on my doormat from people who thought they knew best (incorrectly centered coils being the most common problem). Many of these botched attempts are so poorly executed it means the end of the drivers.

Chris.

All drivers I have refoamed mostly CX50/100 are done  with the shimless method and never had any complaints what so ever!

Congratualtions Leslie I'm sure you are happy with your method of refoaming - but you should see the state of some CX50/100 drivers I have received which were refoamed using the "shimless" method. Just because you claim it as being successful for you doesn't make it the correct way of doing things.

The bottom line is that shims should be used whenever possible - it is the correct way of refoaming & nothing anyone says will change that. I would certainly never encourage any other method if you want guaranteed results.

Chris.

Leslie is very skilled in many ways and I admire most of his work.
I do agree with Chris, though, in that shim'ing is an absolute must when refoam'ing woofers.
Just as important as using the right glue and keeping the workspace clean.
Leslie is either very skilled or just plain lucky - or both.

It's a fact that some people are better cut out for DIY than others.
Leslie may have a good feeling about things, refoaming a.o. From seeing what he has accomplished,
I feel it safe to say, he has and therefore he has a high succes rate but, as Chris have also found out, not
all people have this feeling.
By far.
Some people decide to stop when they find out that their skills aren't adequate and while there is still
a chance of rescuing the driver, others just speed ahead.

The owner of these CX50 never got around to glueing anything.
He removed the old surrounds and it didn't quite work out as in the Youtube video...

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I've seen glue "strings" across the cone and down the center.
I've seen cones that had the outer edge where the old foam sat cut off with scissors, leaving nothing for the new surround to sit on. A full MS150 set...
I've seen drivers with torn cones and the likes.
I've seen spiders pulled and stressed completely out of shape.
I've seen surrounds mounted using building silicone - lots of it.
I've seen deformed coil formers from owners forcing the included cardboard shims down a gap that was only about half the width.
I've seen cones with strange wrinkles and cones that were "extended" using paper to reach out and fit a new non-correct diameter surround.
Hot glue melts some types of foam, don't ask how I know.
Everytime a battle to save an extinct B&O driver and everytime I'd wish they'd asked a pro.
It's not expensive to have it done by a pro. About the same price as one of the cheapest and lousiest replacement
drivers that won't have nowhere near suitable T/S parameters anyways.

Even owners who actually tried to shim everything up correctly can face tough luck.

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This woofer came from a fellow Beoworlder on the other side of the globe. He had it refoam'ed by a pro but
it "didn't sound quite right".
I took this photo when I found foam remains caught and mashed out between the coil former and
magnet center piece. That sticky stuff is very difficult to remove.
The refoam job itself was perfect, the guy who did it just wasn't aware of a tiny piece of old foam debris.
There are many ways for things to go wrong, even if you try to do it right.
Shim'ing and making sure everything sits correctly, is the least thing you can do.

Martin

Dillen wrote:

The owner of these CX50 never got around to glueing anything.
He removed the old surrounds and it didn't quite work out as in the Youtube video...

The kids these days have a phrase that seems to fit this situation.

"Wow.  Just wow."

Finally Martin, you're back!🤒

I'm convinced, because of all these good advises that shimming is a need to do refoaming the right and precise way. However, and I have not done this shimming method before, I wonder if this is really necessary for small diameters like CX50/100 drivers? Other thing is, would people with no experience at all take risks by damaging the cones/spider. I mean, you have to cut out the dust cap (if I have understand this correctly, you have to make sure no dust will come inside the center cone etc. Would be great if someone could make a sort of photo session while doing this refomanig/shimming process!

Leslie wrote:

Would be great if someone could make a sort of photo session while doing this refomanig/shimming process!

Yes it would.  Then turn it into a wiki on the new forum.

Leslie, if you want a DVD of the whole process, PM me your mailing address and I'll send you one.

Martin, I've seen your pictures an they look worse! What do you think these kind of people would handle when using the shimming method. They should keep their hands off refoaming at all!

Rich wrote:

Leslie, if you want a DVD of the whole process, PM me your mailing address and I'll send you one.

That's a nice offer Rich, would you do that for me?

Leslie wrote:

Rich wrote:

Leslie, if you want a DVD of the whole process, PM me your mailing address and I'll send you one.

 

That's a nice offer Rich, would you do that for me?

Of course.