speaker repair experiences?

I picked up a homemade speaker cab at the thrift store today with a 15" Ampeg speakeer in it. The cone has a couple of minor tears, & I was thinking about trying to repair them. Superglue was recommended on one post here, & I believe somewhere on the internets you can get a repair kit. I was wondering if anyone had experience with this stuff/any tips or suggestions of resources to check out.

Thanks
Tom

I wouldn't use super glue. This is very rigid and brittle. Depending where the rip is will dictate what glue to use. If it is close or on the surround (outer edge) there is a lot of flexing here and a rubber glue or liquid latex rubber best suits this application. If the surround is ripped it is best to put a patch of similar material over top of the rip and gluing with one of the above mentioned materials. Any kind of rip on the paper cone itself can be repaired with rubber glue such as 3M Scotch Grip or Some of the Bostik products. Bostik is the glue that JBL used for years and it is an excellent glue, unfortunately I don't have the product number. Coil Former is best bonded to the spider and cone with a fast setting epoxy.

Most of the speakers built by the comapny I work for are actually put together with CA (superglue). They are polyprop cones and mostly santoprene (EPDM) surrounds, though some are foam surrounds.

I have repaired a lot of small tears in paper cones by wiping a small amount of silicone on the back side of the cone with a finger. Anything more than about 1/2 inch or so and it might not stay together under power. You want to be careful if you want to maintain the original sound of the driver not to add too much mass. If you just want the speaker to work, then it doesn't matter.

Hope that helps.

Good ol Elmers. If the tear is greater tha 1 inch, you prolly wanna use someting like a piece of a paper napkin as a medium.

[quote author="SonsOfThunder"]Most of the speakers built by the comapny I work for are actually put together with CA (superglue). They are polyprop cones and mostly santoprene (EPDM) surrounds, though some are foam surrounds.

[/quote]

What bond are you gluing with the cyano? In my experiences this was found to be much too rigid an adhesive especially on the surrounds, and caused compliance tick. I know polypropylene isn't the most glue friendly plastic. One glue I found to work well is Goop, with perchloride, the same chemical used in dry-cleaning. Very sticky stuff, works well on surrounds and dust caps, as well as the spider to basket bond.

I'll check with the guys in rebuild to be 100%, but I'm pretty certain they use it for all the joints. There are a couple of different formulations that they use, I think.

Goop, now thats one I probably would not have thought to use.

Elmers should work great on paper cones! :thumb:

HTH!

[quote author="Butterylicious"]Good ol Elmers. If the tear is greater tha 1 inch, you prolly wanna use someting like a piece of a paper napkin as a medium.[/quote]

That's how my ex-boss, the head of the Speaker & Stereo Store, used to fix small tears in paper cones. He'd use Kleenex as reinforcement. Worked great on the little CTS speaker in my Kalamazoo!

Peace,
Paul

My 2 cents.

I have fixed a few PA speakers not the old gutiar stuff that
has value.

I have used clear RTV silcone. I got the thinner (more runny)
version. I fixed JBL K120 in my monitors that when screwing
in the speaker the drill slipped and it was not a nice sight.
Very big tear you gould have driven a bear can through it!
I worked slowly and even had a nice ridge of silicone
over the tear. I would not do this for a real thin gutiar type but
this repair has been on the road for 20 years and still going strong.

I had a 30 watt celestion guitar speaker that a friend used in a homemade
4 x 12 cabinet. And yes he used this with an SVT for Bass G. So there was a lot of come movement!.
Well one speaker got sick the voice coil opened up. So I carefully cut
away the spider and the surround. I do not know to this day how I did it but I did not damage the speaker cone at all. I cleaned the frame.
Cleaned the gap. removed the dust cap with a small knife blade.
I found the coil was broken on the first turn as the wire took the right turn
as it was going down the coil to the bottom of the coil on the 1st outside turn. I was lucky I removed on turn on the 2 layer coil, reglued the wire back. I recentered the speaker with a shim (remember I removed the dust cover). I then used the same RTV silicone and glued the spider and the next day the surround. Then removed the shim the next day.
Check the speaker for rub and buzz. Then glued the dust cap on. That one has also been going for 20 years.

OK for a different flavor. I had a K120 in horn loaded midrange service.
One died. I found that as the speaker voice coil leads
left the rivit and went down the cone to the voice coil that the flat
voice coil wire was broken under the glue. I scraped the glue and yes a hairline crack in the voicecoil wire BUT it was aluminium in this JBL.
What to do? Well I found some really low resistance silver loaded epoxy.
I removed the aluminium dust cover. No I could not save it. Scraped
the voice coil wire very well and applied the conductive epoxy.
I let it dry and the speaker worked. I took the speaker to a local recone shop. For $5 they glued a new dust cap in place. I was very carefull
that the dust cap did not short to the conductive epoxy. That one
has been going for 18 years. But that speaker is over 30 years old by now.

Take your time you can fix it.

Yes here I use to get visits form the Local Loctite glue sales guy.
We have a consumer Jensen speaker plant nearby and they used the toughed "Prizm" black cyro glues for speaker assembly.
The reason was it was cheap. It glued well. Not much fumes.
It was applied with phemuatic hand applicators so there was no waste.
It it dried very quick so less baking was needed. Yes Bill Y they do
yes special "super glue" for new speaker assembly.

IIRC, Ted Weber recommeds layers of tissue paper (the kind in gift wrap boxes, not the other variety) and elmers for tears in cones on guitar speakers. If it's a small tear, you can use clear fingernail polish.

second the motion for elmers and paper towel. Its ugly, but it'll get you through a gig.

Elmers is not very good for it, Try this stuff you can get at craft stores called Tacky Glue. It dries nice amd flexable and works great. You have to thin it out quite abit and then just apply it around the tear and put on some tissue paper then more of the glue, then tissue for quite a few layers. Water the glue abit thinner then elmers. When you get it abit watery it actualy disolves the tissue paper into the cone abit. I do alot of this for people around town, and this is by far the best way I have found. Elmers Tends toget brittle with ago, and it not nearly as flexable as the Tacky Glue. And if you want something abit better then tissue paper, in hobby shops you can get this paper used to cover model airplanes. Its very thin and light and has a very heavy grain. In the end it seems to do the same job as the tissue paper, but goes on alot easier.

adam

While were on this super glue thing, I just heard a good one. A kayak buddie of mine runs the Western States 100 every year. It's an ultra-marathon 100 mile race from Squaw Valley Lake Tahoe to sunny Auburn, California. There is a 24 hour time limit and 30,000 feet of climbing. Feets don't fail me now!

Anyhoo, he was talking about some of the radical measures that people take to finish the race. Some freaks actually have their toe nails surgically removed before the race. They grow back a few months later. Others, if they get a blister, cut the blister open, drain the fluid, inject it with super glue, and on you go! :twisted:

I'll stick to the nice cool river, thanks.

So how many layers of tissue are we talking? 4 or 5, or a couple dozen?
I did some work on it, but I'm not sure how much I helped things.

Tom

i just go untill it seems sturdy again, for punctures i usualy do 2 or 3, for tears and i go are 5 or 6. If you can access the tear on the backside of the cone also, just do like 4 layers on each side and let it dry. and you will be in great shape. Just remember if you are not sure if it is enough give it a few hours to good and dry, When the glue is wet it will seem like it is still to weak. You can always apply more after it is dry.

adam

I think I did a fairly good job on it, but on low notes (really anything lower than low A on a guitar) I get a rattle. When I plug a bass in the rattle gets huge. I'm thinking this is a separate issue from the tear problem. Is this likely to be fixable, or is this destined to be my high-notes-only speaker?

Thanks for all the advice so far--it's been very helpful.

Tom

Sounds like time for a recone or a new speaker...

Make sure the speaker terminals are not connected to anything, and the speaker is not mounted in an enclosure. Cone facing up, Tap gently on the cone of the speaker with your finger. It should give off a dull thud. If you hear rubbing or scratchiness the coil is most likely rubbing. You can further test by connecting a power amp to the speaker, and sweeping the speaker with low level 10-20 Hz. sine wave. This will show up any rubbing or compliance tick that may exist.

[quote author="hodad"]I think I did a fairly good job on it, but on low notes (really anything lower than low A on a guitar) I get a rattle. When I plug a bass in the rattle gets huge. I'm thinking this is a separate issue from the tear problem. Is this likely to be fixable, or is this destined to be my high-notes-only speaker?

Thanks for all the advice so far--it's been very helpful.

Tom[/quote]

Measure the impedance.
Gently check the travel of the voice coil. If you hear it scratch, then you've prolly got a split voice coil. If the impedance is really odd, you may have a burnt voice coil.
Ifin you have a function generator, sweep it and pay close attention to how the speaker reacts. It's far from uncommon for voice coils to become sorta unraveled over time, in particular woofers that have had it hard.

It also could be a warped voice coil from it heating up. Which is not to hard to fix, it just takes some time. Everything said above also applies to if the voice coil is warped. If impedance checks out and you hear a scrapping when you push in on the cone repeatedly, or when feeding it a low sine wave, Which is the better way to test for this. Since you could just be pushing a little to much to one side causing the voice coil to scrape. Over at www.weberVST.com they have instructions on how to fix a warped voice coil. but if it is warped, you might as well just have it reconed if you can afford it. which weber VST and countless other can do for you, I highly recomend weberVST for this job. Were ever you go, just make sure it is somewhere the specialises in instrument speakers, it will be cheaper. The guys that do hifi speakers charge alot more.

adam

Unfortunately, Weber no longer recones, except for their own manufactured speakers. They do list some other recommended reconers on their site.