Watkins paper and poly cone refoaming.

To help those that want to DIY refoaming Infinity woofers, here is my preferred method, step by step.

First thing I want to mention is in the photos it may look like I am cutting and or using a knife cutting toward myself. I avoid this whenever possible a trip to the ER will spoil your day refoaming fast, so please use the utmost care and be safe!

A few tools are needed to get the job done (see photo) I prefer a fairly sharp exacto knife for cutting off old gaskets and a 1" stiff blade putty knife ground at a sharp 45 degree angle on the blade for removing old foam and glue residue. I've used Weldbond glue found at most hardware stores and have had good success refoaming both paper and poly cone woofers. The product goof off is a life saver when it comes to getting the very sticky and stubborn glue that Infinity used on poly cones.



Watkins Stereo Link for those that aren't into DIY and want it done by the Pro's.

The woofers I'm working on are a pair of Watkins paper cone woofers from a pair of QLS and two pair of poly cone woofers from Kappa 9's

I usually start on the outside and work in. Start by removing the old gasket, leaving the dust cap for later to keep debris from falling in to voice coil. Save everything you can, the old paper gaskets can be reused by carefully peeling the first layer off which the glue has penetrated. Most of the time you will need to cut both underneath the gasket as well as the outer edge to prevent tearing. (see photos)
I prefer to clean things up as I go, so once I'm done with the refoam the first thing to come off and happens to be the last to be put back on is ready to go when the glue drys on the surround YMMV.

Once the gasket is removed scrape the old glue off with a sharp putty knife, get as much as you can off. On paper woofers scrape off glue from the cone with your fingernail till there is no more old foam visable, there will be old glue still there but that is ok. I would not recommend using goof off on paper cones, only poly.
Poly woofers you can use a pen knife to remove most of the glue. Becareful not to score the cone, you won't be able to get it very clean but that's ok. Once you have the outer basket edge scraped and the cone scraped. Use a cloth and a generous amount of goof off to remove the rest of the glue residue.(see photo) Becareful not to get goof off on the dust cap or spill it over the edge and get it on the spider, which would be bad news. This pair of Kappas have foam dust caps which I tackle later by using the same method as the Waktins. I use a small swiss army pen knife that isn't very sharp to carefully remove old dust caps by working the tip around the edge, working deeper toward the center till I can get a finger underneath and work it loose. Depending on how well it is coming off or not coming off you may need to lightly score the edge of the dust cap where the glue ends to prevent the cone from tearing.
The Watkins dust caps are felt which is very forgiving, if you wrinkle it wet it till it is soaked with water and form it back into shape, let it dry over night and it will be almost good as new.

Here are the photos showing how your woofer should look after scrapping off the old glue. Removing the old dust cap and the poly cone after cleaning with goof off. Once I have cleaned all the glue off I use (dawn dish washing liquid) soap and water to remove any residue from the goof off to make sure I've got a clean surface to glue the surround to.

More later...

Unfortunately dust caps are no longer available

I would have to check with Mr Watkins as to availability of other woofer parts. IIRC from past posts here there aren't any OEM parts available. But Watkins Engineering has found a source for replacement of the entire dual voice coil woofer for $149 and it will be a limited run.

Now the fun begins (see photo) this is the Kappa 9 woofer shimmed with the inner surround just set in place. You can use just about anything to shim a woofer, business cards, plain paper or thin plastic strips. I prefer to use four shims a crossed from each other just tight enough for the cone to be held in place just above the basket. This time I used a thick paper that actually was a paint card from a hardware store and it wasn't quite enough so I added another plain peice of paper behind it. With Weldbond you usually have 10-15 minutes to work the excess glue out pressing with your fingers on the front and back of the cone at the same time. Each time I take the excess off with a damp cloth so there aren't any glue globs.

With the very well built Kappa 9 woofers came a challenge. They have cast aluminium basket with a large outer edge. Normally I prefer to use small spring loaded clamps to hold the outer surround in place till it drys. I've run into this before on JBL's as well and reuse the old gaskets or replace with new and use the gasket to clamp to.

Once clamped down I've found it to be better safe than sorry, so I remove the shims and check voice coil clearance by hand placing four fingers equal distance from the center and pushing down and letting the cone spring back on its own, hasn't failed me yet. Once voice coil clearance is ok no sense in wasting time I put on either the old dust cap or as in this case a new one. This woofer will be ready to play in about four hours.