advertisement


Speaker dust caps

Mr Pig

^'- -'^
Quick question.

I've just bought a pair of speakers with destroyed dust caps on the bass drivers, the usual pint sized perpetrators. I've ordered two replacement polypropylene dust caps but I'm not sure what the best glue to use is? I do have proper surround glue but the contact area is very small and you're effectively sticking plastic to plastic. Super glue or super glue gel will stick them all right but no time to reposition if you put them on wrong.

Any suggestions?

Thank you.
 
Plastic in general and especially stuff like polypropylene are notoriously difficult to glue. There are special activators to make super glue more effective with plastics but you may be better off with something trad like Bostik... I'm sure there'll be an adhesives technician or some such along shortly to give you the low down on it though!
 
Here's the problem. From "Gorrila Glue" site:

"Recycled Symbol 4: Low Density Polyethylene (LDPE)

LDPE is used to make squeezable, less rigid bottles, garment bags and even some clothing and furniture.

What’s the best glue? LDPE has a very low surface energy; which basically means it’s very slippery. Glue isn’t recommended.



Recycling Symbol 5: Polypropylene (PP)

Some of the items made from this type of plastic are bottles caps, drinking straws and pill bottles.

What’s the best glue? Similar to LDPE, Polypropylene has a low surface energy. Some industrial adhesives may be effective, however surface preparation will likely be required."
 
I'd recommend making one or two 'handles' out of scotch tape to hold onto while maneuvering the cap into place. Should make getting the position right the first go much easier. And since your new dust caps are plastic there shouldn't be an issue removing the tape afterward.
 
Does it take a minute to set?

It's a clear gel, with 5/10 minutes of 'open' time. Try some on some scrap pieces first.
I would apply glue to the cap, position, then remove to ensure there is sufficient glue on both surfaces if the contact area is minimal.
Maybe lightly scuff up the contact surfaces first.
 
Maybe lightly scuff up the contact surfaces first.

Actually, this is a concern. I need to remove the remnants of the old caps and I'm not sure how easy that will be. It's easy on paper cones but plastic is difference. My worry with sanding is that dust gets into the coil gap. I'll need to stick some wadding or something into the hole first.
 
Stuck the new caps on. I think that glue is probably very similar to the glue used originally. One of the old caps was already off and the other pushed in. The pushed in cap peeled off cleanly with the glue still tacky after all these years.

The speakers in question are Wharfdale 507.2s by the way. Dog of a speaker but it's just for my son to use in his office. Incidentally, really not obvious how those drivers are attached!
 
Wharfedale made a big thing about the bass driver mounting back in the day. It’s actually placed in the hole and rotated maybe 10 - 15 degrees. There is actually a special tool that was supplied to dealers, basically a steel bar with two rectangular shaped pins that locate into holes in the frame of the bass driver.
The tweeters come out by removing the thin black facial plate on the tweeter to reveal I think three screws.
 
Wharfedale made a big thing about the bass driver mounting back in the day. It’s actually placed in the hole and rotated maybe 10 - 15 degrees.

I figured it had to be something like that because of the slots in the basket. There is no access to the rear. Lot of trouble to go to for not much gain although they were very tidy looking speakers in their day. Big sellers too, helped by stellar reviews. Shame they sound crap!
 


advertisement


Back
Top