B110 repair

[AndyNC]

Hi Guys and Gals,

I'm new here but always been interested in HiFi, built a few amps many years ago and currently use a Quad 33/303. I have a technics 1200 in the loft with an SME arm and grado cartridge not been used for decades but life moves on. Still got the vinyl though.

Many years ago ( mid 80's) I built a pair if HiFi Answers TLMs. Unfortunately my wife thinks they are too big for the house and they are confined to the Garage/Workshop. (They've not been in the house for many years)

I noticed a drop off in the output of the B110 on one speaker so I swapped the units over and the problem lies with the crossover. I've ordered a new set of Caps which should arrive today. So one problem out of the way I hope.

When changing over the units I notes that there was a 1.5" cut in the cone on one of the B110's. Given that the speakers are not on the ideal listening environment I'm after suggestion on how to do a "quick fix". Actually I'm more interested in what not to do, ie what glues/tapes not to use that may dissolve the bexdryne cone.

So I was thinking of a small piece of PVC tape along the cut or run a little superglue along it.
Would that be ok chemically ie is the glue going to be OK. I know it some what of a sacrilege but my ears aren't what they used to be and I can't afford a new unit at the moment.

Cheers

Andy

 

[JonSnell Electronic]

I use EvoStik. It is flexible when dry. Superglue is brittle!

 

[fatmarley]

I'd use PVA and maybe a small strip of paper, but fitted to the back of the cone, if possible.

 

[Bon]

Since the cones are made of bextrene, a synthetic material, I would suggest using some of the car windscreen sealant sold in auto spares shops. It remains flexible and seals really well. That's its purpose after all! I repaired some holes in cones of a vandalised pair of speakers over 10 years ago. They are still going strong. You lay down a trail along the cut in a thin streak and smooth it with a lolly stick or similar. No need to extend much each side of the cut. No re-inforcing is necessary.

 

[Mr. dB]

I wonder if model car or model airplane cement might work? Bextrene is similar to the styrene plastics used in models.

 

[VaNarn]

The bextrene material will be effected by the solvents found in some adhesives.A split in the B110 cone is a sign of ageing or fatigue of the material .An impact resistant super glue may do the trick,although I have not tested it.Replacement of the speaker or a re-cone ,if something suitable can be found,are safer long term solutions.

 

[irext]

I would try some black Sikaflex. It's like Silastik on steroids. Since the cones are Bextrene and are essentially black, it wouldn't look ugly. The Sikaflex will still be there long after the rest of the cone has dissintegrated! It's very good stuff.

 

[Bon]

I would try some black Sikaflex. It's very good stuff.

I second that. Be warned however that it has quite a long curing time. It will still be tacky a couple of days after application. It will stay flexible for ever though.