Re-foamers: wtd with thin material under the foam along the cone's edge?

[Johnny_Law]

What's the best practice here? Not all the time, but sometimes, woofers have this thin piece of material underneath the original foam. I've noticed it mainly with foam that attaches to the outer side of the cone.

Has anyone else noticed cones with this piece of material?

Do you ...

• Surgically remove it?

• Refoam over it / onto it?

• Do something else?

Thanks in advance,
Ryan

 

[spark1]

I've always assumed it's there as a glueing surface. Interesting question though.

 

[grillebilly]

I always thought it was part of the surround. The glue is stronger than the foam, so the surround gets "separated", and a portion of it is left on the basket. Very common in the automotive world, as the adhesives are so strong the gasket splits in two. Half on each mating surface.

 

[spark1]

I always thought it was part of the surround. The glue is stronger than the foam, so the surround gets "separated", and a portion of it is left on the basket. Very common in the automotive world, as the adhesives are so strong the gasket splits in two. Half on each mating surface.

 

[grillebilly]

Scrape it off completely.

 

[spark1]

I think the OP is describing something different (and not common to all cone edges). If I'm right, it is there intentionally. Trying to remove might damage the edges of the cone.

But yes, if it is residue from the old foam/glue it needs be removed or at least completely smoothed out. Finger and thumb friction, alcohol, acetone and even sandpaper can all be handy in this case...but if cones are not paper, care needs to taken with chemicals.

 

[ivandezande]

The cone side? It's always peeled off cleanly for me, paper or poly. Probably wouldn't be terrible to leave it either though.

 

[RW Oliver]

What's the best practice here? Not all the time, but sometimes, woofers have this thin piece of material underneath the original foam. I've noticed it mainly with foam that attaches to the outer side of the cone.

Has anyone else noticed cones with this piece of material?

Do you ...

• Surgically remove it?

• Refoam over it / onto it?

• Do something else?

Thanks in advance,
Ryan

what make is the speaker?

 

[gdmoore28]

As others have pointed out already, the photo is showing the remainder of the original surround where it was affixed to the cone edge.

GeeDeeEmm

 

[Johnny_Law]

The driver is a Peerless out of a Snell K/II. I've also seen this kind of thing on a few other drivers ... trying to remember which ones. On those, I've usually used a sharp blade to remove the outer free floating circumference while leaving the part attached to the cone intact - not to mention that the part attached to the cone hasn't wanted to come off without ripping the cone, iirc.

Sounds like that, or removing it completely if you can, is the best practice.

 

[sKiZo]

Can't say as I've ever had that sort of thing happen.

Wonder if the old dental floss trick would work? Carefully lift a small section of the remaining surround, insert unwaxed floss, and use that to carefully "saw" the rest. Works well with body tape on cars anyway. You may still have a bit of residue, but that shouldn't be as much of a problem.

 

[spark1]

As others have pointed out already, the photo is showing the remainder of the original surround where it was affixed to the cone edge.

GeeDeeEmm

While i continue to believe that some cones have a "glueing edge", now that i can see the OPs photo on a full size screen, it obviously has a lot of residual material from the old surround (on both the cone and.the basket).

 

[RW Oliver]

Is there a paper ring under the foam residue on the frame?

 

[louder]

Judging by the pic, there's still a bit of the old surround stuck to the frame, it and the old glue should be removed either with solvent or a sharp blade.
Of course, leaving a thin layer of the old adhesive that is well adhered to the frame can act sort of like a primer to new adhesive but if removed and cleaned correctly, its not an issue.

 

[Johnny_Law]

Thanks all for the comments and nice work to those who spotted remaining foam residue on the frame and the cone edge - eagle eye'd, you lot!

some cones have a "glueing edge"

Have you seen this kind of a "glueing edge" on other cones? I am racking my brain to remember where I've seen this before but still at a loss. It may have been on the other Snell cones I've done - the Vifa ones.