Adhesive choices

[uarnutz]

I am new here so, forgive me if I breach etiquette. I am preparing to do my first speaker surround refoaming and I have read countless threads on various forums. Not surprisingly, there are differing approaches e.g., using a tone generator vs. shims for centering. Ok. I can make an informed decision on that. What has me a little more concerned is the lack of info on best adhesives to use. Maybe I just did not look in the right place but, do we have any actual specs from the speaker manufacturers for the adhesives they used? I am working on AR speakers and this forum has excellent resources, including original engineering drawings. There they specify particular adhesives by name for the surrounds and cone (i.e., Hapcon 400 and 500, IIRC). Does anyone know what these are/were?  Just checking to see what we are basing our decisions on for this.  I would tend to go with the original manufacturer spec, if practical.

[JKent]

Dunno about original but I recommend using only the white water based glue with paper cones. It is very forgiving, you can spread it with a finger, it cleans up with water and if you misalign the pieces you can pull them apart before it dries. The solvent based stuff is needed for plastic cones but it’s a PITA to work with. My AR-93s had been refoamed using the nitrile glue and although they worked they looked so awful I sent them out to Bill LeGall to be redone. Much prettier now 😊

[uarnutz]

Thanks. That's useful input. I am pretty sure the white (PVA) will not do any harm. I was wondering more if it is flexible enough and seals well. As far as I know, they are not meant for non-porous surfaces like the speaker cage and they do not remain flexible. I would have thought one of the urethane adhesives would be more suited to this though they are probably harder to work with. I am also leery of solvent based adhesives for a PU foam.  Sorry for all the questions. I know just enough to be a PITA on this since I used to be involved in sealants and adhesives professionally at one point. Hopefully my questions will help others understand as well.

[RTally]

I prefer to use Aleenes Tacky Glue (a white PVA). It is readily available at craft and fabric stores, among many other places. I like that you have more than 30 seconds to position the surround (typically, Aleenes allows alignment for 5 minutes or more). The solvent-based adhesives cure quickly. I am slow and methodical in my work and I have little time to ensure proper foam positioning before the adhesive cures.

The flexibility of the glue after curing is not important. Where the glue is placed is not subject to being flexed (better not be!). I have never had a bit of trouble using it to glue foam surrounds to bare metal baskets. Also, as with any adhesive, you want to only use as much as is necessary to avoid adding too much mass to the cone-surround edge.

I prefer to use a tone to magnetically center the voice coil. I see no sense in removing a dust cap. It requires additional effort to remove and requires care and effort to replace. I also manually depress the cone to ensure the VC is centered. With Aleenes, I can do this at my leisure before it cures.

Finally, it is easy to overthink these things. You are not installing surrounds like they would in a factory, with jigs and specially formulated adhesives, where fast curing is desirable for production. So don't lock yourself into doing assembly as the factory did if you do not have the same facilities available. I refoam my speakers on a table by hand. I use appropriate materials and techniques.

If you are not sure or this is your first refoam, I suggest refoaming a sacrificial woofer such as a thrift store find. Nothing like some experience to learn the ins and outs of a task.