SDA SRS SW150 Passive Radiator Repair

250GTLusso

As this is my first original post, I apologize in advance!

I am a long time Polk Audio fan. I bought my first pair of SDA 1C's new back in September 1987 (one of the first pair of the new style Walnut capped enclosures to reach the west coast, SN6522-later exchanged for 6533 due to chipped veneer, and SN6545 - Blade-Blade IC) and I was hooked!

I listened to them for 27 years before I bought my second pair of Polks, the SDA SRS, a little over a year ago. I had always wanted the SDA SRS's, but couldn't afford them new (that's why I bought the SDA 1C's). They were just spectacular. Later last year I then picked up a pair of SDA 2B's ($150) and shortly after that a pair of SDA 2.3TL's ($400 - a smoking deal from a really nice guy), and just last month another pair of FLAWLESS SDA SRS's ($400 - yes, I drove away like I stole them!) as I wanted to use the SDS SRS's in my HT rig for front and rear channels.

Now the reason for my post. My first set of SDA SRS's, while in excellent condition, have an issue. The PR in the left channel has rust! It looks like something was spilled on it a long time ago, and at the bottom where the liquid collected, the paint has lifted and flaked off and started to rust underneath. Normally I would just remove the rust with some scotch-brite and touch it up with some black satin paint, but I am concerned that the Butyl Rubber surround of the PR has started to lift off from the basket flange (since its actually attached to the lifting paint), and will eventually develop an air leak if left unattended.

I am looking for recommendations on how to address this issue. I was thinking about peeling the edge of the surround up off the basket flange and prepping and painting the basket flange and then re-gluing the surround to the flange. Has anyone attempted this before? If so, what adhesive would you recommend?




Appreciate any and all suggestions, especially any do's and don'ts.

I have attached a couple photos of the collection (all of them are still stock - I plan on modifying the SDA 2.3TL's first).

Thanks!

westmassguy

There are three types of glue used for rubber surrounds. The 1st is a solvent based glue, which melts the skin of the rubber and bonds it to the metal frame. It's used by the OEM under tightly controlled conditions. The 2nd type is also a solvent based glue, but doesn't attack or melt the rubber. It's similar to contact cement. The 3rd type, is a very thick form of Cyanoacrylate. Since it's a small area, I'd gently lift the rubber as far as it will go without tearing it from the frame. Remove any loose paint from the frame, and if possible any loose flakes from the rubber. Touch up the frame, then use a brush-on Cyanoacrylate. Apply it to the rubber only. Use toothpicks to keep the rubber away from the frame, until you have a uniform coat of glue, then remove the toothpicks, and GENTLY press the rubber down. It should bond instantly.
If you applied too much glue, it may ooze out. Do not try and remove it, as it will bond to whatever it touches.

250GTLusso

Thank you Westmassguy!

That sounds doable. Any particular brand of "brush-on" Cyanoacrylate? I have only used the "thin" type in the small "super-glue" dispensers (Loctite).

Love this forum. Cant wait to start the mods on the 2.3TL's.

westmassguy

You can't get the glue I use, but a close alternative is Crazy Glue. It comes in a small bottle, green label, with a red cap. Brush is attached to the cap. It's a thinner than the stuff I use, but thicker than the regular Crazy glue