Advice needed - Removing new foam from paper cone

noprayer

noprayer

Super Member
I'm finally getting around to some old projects lying around the house. One of those projects is attempting to resurrect a pair of old Yamaha NS-325 speakers. I decided a few years ago to have a local person advertising on C-list re-foam the woofers. Long story short, he did a terrible job and i had to cut the surrounds to free the cones in order to prevent damage. I now need to get the relatively new foam of the rather fragile paper cones. Can anyone offer any tips or tricks? I searched the forum and didn't come up with much. (probably not using a very good query) Thanks in advance.
 
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when I changed the the new foam (I bought the correct refoam kit) I used a sharp steak knife
to saw through the fresh glue it worked well just take your time
 
The key is to not use anything sharp. When I refoamed some Boston A70's, the old foam was rotted and literally rubbed off, easily. Perhaps use a butterknife? In the very old days bicycle inner tube repair kits used to come with a 1" x 1" square piece of metal with cheese-grater serrations to rough up the rubber before gluing on the patch. Something like that (or perhaps a bread knife?) to rub lightly against the foam on the paper cones to make the foam come off... It's is NOT necessary to completely remove the foam. Nobody will see the foam you do not remove. It's only necessary to get it flat enough so that the new foam will stick and seal properly. Please remember that. Just like with bicycle repainting, it is NOT necessary to strip the paint down to the metal, and that will actually hurt in most cases and is unnecessary.
 
Maybe a heat gun/hair dryer (not too hot) to help soften the glue. Or if nothing else, put it in a sunny window for a couple of hours.
 
Warming them up in the sun did the trick and i was able to get all the foam off the cones with my fingers alone. No tools. Now to find a reputable re-foamer in the Milwaukee or surrounding areas. Anyone have any recommendations?
 
This is a 20-mins job even for an amateur, you can do it yourself! Anyone who had a 2nd grade art class is well-prepared to re-foam their speakers!
 
I beg to differ. First off, these woofers are unobtainium, so if i ruin a voice coil I'm screwed. Second, If i do not feel like i am qualified to cut the dust caps off, properly shim the coils, properly attach the correct surrounds to the recessed cast aluminum baskets and get it all done correctly then i guess i am not as talented as a second grader with an art class. Lastly, I can afford to pay a pro to do the work.
 
Ahhh. Please watch the video about rebuilding a completely GONE / destroyed speaker, to realize this is not a rocket science thing, speakers are more like 18th-century art projects. Note: The video's author is a little crazy, he uses epoxy for everything!


Just an FYI half the scary-sounding refoam steps are often unnecessary. I re-foamed my speakers WITHOUT cutting off the dust caps WITHOUT shimming the coils and they work PERFECTLY. I just had to run 2 beads of glue per speaker. If you do it and the voice coil happens to show friction with the magnet you can always re-do it or take it to a pro.
 
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Once again, does anyone have any recommendations for a good pro in the Midwest i can send these too? Thanks in advance.
 
Removed the woofers and take them to a workspace OUTDOORS with lots of fresh air.
Take narrow paper towels and use MEK (Danger, toxic fumes) on the paper towels to dissolve the old foam and glue,
and gently rub it free with your fingernails.
It should NOT affect the paper woofer cones. It's kind of a tedious messy job, but not difficult.
 
hjames said:
Removed the woofers and take them to a workspace OUTDOORS with lots of fresh air.
Take narrow paper towels and use MEK (Danger, toxic fumes) on the paper towels to dissolve the old foam and glue,
and gently rub it free with your fingernails.
It should NOT affect the paper woofer cones. It's kind of a tedious messy job, but not difficult.
Click to expand...
I was able to what you suggested, minus the chemical, by just leaving them in the sun to warm up. Then i was able to get all the foam and glue off with just my fingers. Thanks!
 
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