I searched for information regarding refoaming polycones and couldn't find anything on AK. I imagine it's been talked about, so if anyone can guide me right to a former thread...that would be wonderful.

Otherwise, my question is, what is the easiest and best way to remove old foam from the polycones? I have a pair of RS IIIB's that i'm refoaming and the old foam just doesn't want to come off. I'm afriad of using any solvents in fear of damaging the cones. Anybody know something that works well?

hello,
the last pair of reference monitors 12" infinty drivers I did took me ages as I sat at the dining table with cotton tips and acetone and a pair of fine tweezers. Dabbing at the foam and picking it off and cleaning the part before moving on to the next bit. By the time I had finished (it took several nights) the baskets and the polycones looked like they were brand new- not a remnant of foam anywhere. The new surrounds sat beautifully and you would swear it was completely original. Acetone was the only thing that touched the foam/glue and didn't cause any damage. I'd spot test it first though as it can eat up plastic very easily.

I have done a few poly cones that I could not get all of the old glue off of. I got the bulk of the foam off and used contact cement over the old glue as it seems like that was what was already there. Worked fine for me. Make sure you have the foam where you want it though. Contact cement is very unforgiving of misplaced foam. YMMV.

Possible use of a Dremel and a very light touch to clean up the foam remnants?

I've got some 9bs in need of foam. I'll be interested in getting more feedback as well.

good post!

I do refoaming professionally. I've done scads of polycones. I will generally use an Xacto knife blade which I have deliberately blunted (broken off tip, then ground to a curve) to scrap off the final residues of polyurethane. This has the advantage of slightly scuffing the surface of the polyprolylene, and this helps the speaker glue get a grip. In some cases, I will then give it a final going-over with ethynol.

Some polycones are highly polished. When I encounter these (and it's rare) I have a special etchant that I paint the outer "ring" of the cone with. This removes the polished surface and etches rough, clingy surface detail onto the cone. WARNING: use the etchant outside!

Whenever you are pressing a knife blade against the cone, it is of paramount importance that you place the fingers of your other hand UNDER the cone, to hold it in a stable position and prevent skewing. Excessive skewing during the prep process will cause the enamel on the magnet wire of the voice coil to abrade.

I do NOT recommend using a Dremel tool to remove foam remnants unless you are wearing OSHA-approved safety gear. Unfortunately, a Dremel tool causes a great deal of heat, and this creates vapors, fumes and particulates -- which can be toxic.

Fred Longworth

Fred,

What adhesives do you use for refoaming?

I understand that the contact-cement adhesives often used with paper cones may not be suitable for poly cones.

Goo gone found at your local hardware or grocery stores will clean up glue residue and leave your poly cones clean as can be :thmbsp:

Thanks for all of the replies. I went with the ever-popular "scrape lightly with a razorblade until you cannot scrape anymore" method. I think next time I might try some goo-gone for the outer metal part. Luckily, everything turned out well and I have completed my first successful POLYCONE refoam. Actually went a lot more smoothly than the refoam for the Jensen System B's i'm doing today... It's been a bit of a nightmare. Anyways, here's some finished pics for your viewing pleasure :banana:

Now I just need to get some material to replace the torn up foam that is around the EMIT and Mid and these'll be good to go! :thmbsp:

Nice work. I am curious to hear a set of the RSIIIB speakers. My dad (in NY) just picked up a set. My brother, who could care less about a speaker if it fell out of the sky and hit him on the head, said that it was the first speaker he heard that didn't sound like all of the other speakers he had ever heard. That was a compliment from him. I think he may be adopted :scratch2: .

Looks great, I too am interested in the adhesive, as I need to refoam some RS-2001 surround speakers with the clear cones. Will the Titebond/Weldbond be good enough?

Weldbond will...

I've given my Watkins woofers numerous tests at house shuttering db's :)

Two years and still going strong!

If you don't believe me, ask the guys at the last fest what my normal listening levels are and then ask if they think house shuttering might be extreme!

Weldbond works, trust me!

I've got one more question for all of you -- regarding my RSIIIb's. One of the polydome mids has a puncture in it that causes it to buzz slightly. Is there a place where i can order just the polypropelene dome (diaphragm), or do I need to get a whole new mid? It appears the diaphragm is part #751-2417. I found one here http://www.speakerrepair.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=10-226&Category_Code=Infinity-Diaphragms, but it is listed as a 2" voice coil polydome diaphragm. According to my spec sheet it needs a 2.5" version. Is this the right part?

Weldbond will...

I've given my Watkins woofers numerous tests at house shuttering db's :)

Two years and still going strong!

If you don't believe me, ask the guys at the last fest what my normal listening levels are and then ask if they think house shuttering might be extreme!

Weldbond works, trust me!

Thanks.

Rommaster, what did you use for glue?

Now I just need to get some material to replace the torn up foam that is around the EMIT and Mid and these'll be good to go! :thmbsp:
Try the Foam Factory: thefoamfactory.com/ (http://www.thefoamfactory.com/). I just received an order of a half sheet of 1/4" charcoal regular foam to replace the foam pads on my RS-IIIbs. They also have speaker foam (for making foam speaker grills), but that seems a little too transparent to be used for sound deadening.

I've got one more question for all of you -- regarding my RSIIIb's. One of the polydome mids has a puncture in it that causes it to buzz slightly. Is there a place where i can order just the polypropelene dome (diaphragm), or do I need to get a whole new mid? It appears the diaphragm is part #751-2417. I found one here http://www.speakerrepair.com/Merchant2/merchant.mvc?Screen=PROD&Product_Code=10-226&Category_Code=Infinity-Diaphragms, but it is listed as a 2" voice coil polydome diaphragm. According to my spec sheet it needs a 2.5" version. Is this the right part?
Per my RS-IIIa/b spec sheet, that diaphragm is EXACTLY the one you need. Part number exactly matches what's on my sheet.

Per my RS-IIIa/b spec sheet, that diaphragm is EXACTLY the one you need. Part number exactly matches what's on my sheet.

PERFECT. Thanks. Also, foam factory looks like a good bet. Gotta order a sheet so I can finish these up

Rommaster, what did you use for glue?

I actually got my glue from ReEdger. It's the same glue that I have gotten from him for paper cones. He advised me that it works great on both paper and poly's. It's easy to work with stuff -- quick drying and nice and tacky from the start. It actually reminds me a lot of "Eileen's tacky glue" in consistency. You'd have to talk to him to find out what the deal is. :D

Thanks.

I'll need to start putting my orders in for foam with him, and for lamps from dwojo, soon enough.

http://www.speakerdoctor.com/

I took my RSM to the Speaker Doc and he fixed them up like new a few years back and they are still going strong. And vary reasonable price.

You can mail them in too.

Greg

Scientific Commodities
(aka Global Adhesives)
Lake Havasu City, AZ 86403
1-800-331-7724

I get my adhesives from the above company. They make a broad line of adhesives and etchants for the speaker service industry.

I use WD-32 White Surround Damper. I use full strength. WARNING: use with good ventilation as this off-gasses a small amount of hexane.

Fred Longworth