• The move to the new server is done. There are some software and database maintenance updates in process. This has us passing the hat around to help out. We appreciate any donations. Seriously, even a dollar helps. The payment page may be found here - https://www.audiokarma.org/support.html

Kappa 12 REFOAM - DIY or Professionals only?

drumman2112

drumman2112

Active Member
Be careful what you ask for because you just might get it! For Christmas I asked for a refoam kit and new polydomes for my Kappa 8s. I got them. The refoam kit is from Simply Speaker. The kit came with the surrounds, glue and dust covers BUT no shims.

On one of my 12s, the surround is completely gone. Sure it makes it easy to prep for refoam but this the condition it was in when I got them. I wonder if the voice coil has moved or shifted. The refoam kit came with no shims. WTH? :scratch2:

I have never done a refoam before but I don't think its past my limits. I want the 12s to be as close to spec as possible.

With no shim, I feel that it would be better left in the hands of a professional.

To the ones that have refoamed Kappa 12s before, did you use shims?

Any tips or warnings I need to be aware of if I do it myself?

Thanks guys, this site has been a tremendous help to me.
 
Register to hide this ad
The kits i got from simply speakers to refoam my kappa 8's woofers didn't come with the shims either so i called simply speakers and asked them for the correct shims for my woofer, all they are is a couple pieces clear plastic or lexan that you put between the pole and the voice coil to hold the woofer perfectly aligned, get them and the job will be much easier.
 
to shim or not to shim....

I've done dozens of speakers, including 12" infinity and have only shimmed on one occasion(not the infinity). I glue the surround to the cone and let it dry. then I use big paper clamps to secure the surround to the basket, make sure I have travel in and out , and then remove one clamp at a time and glue. repalce the clamp and move on to the next until all is glued. i sometimes use a battery to help center but not usually.

I think the item of biggest importance when re-foaming is the glue. You want it to set up fast enough so that things don't move around, but not so fast as you have no time to work.
 
When I refoamed a pair of Kappa 8 woofers I did not use shims, but rather the method described above. If you are patient and meticulous you will get a better result cosmetically than shimming, as well as no problem mechanically.
 
Sir.Byrd said:
When I refoamed a pair of Kappa 8 woofers I did not use shims, but rather the method described above. If you are patient and meticulous you will get a better result cosmetically than shimming, as well as no problem mechanically.
Click to expand...

My concern is the 12 with no surround left on it at all and that the coil may have been disturbed by being moved or from the cone being pushed in. The dust covers are shot so I am going to replace those when I do with the refoam. Anyway to tell if the coil is out of alignment?
 
I don't recall there being a gasket... but that doesn't mean anything other than my memory sucks!

If you are replacing the dust covers and are more comfortable shimming, then do so. Be careful when replacing them because I am uncertain that they are sealed because they are a sort of foam. If they are sealed you could use plastic or paper, but if they are not sealed you'd need felt or cloth. Of course if you can get original dust caps that would be best.

To check the coils I would test them with a multimeter to measure resistance and report back here. An easier test than that is to connect a known good battery (1.5V) to the terminals, if the cone does not move you've got a dead coil, or a break somewhere in the tinsel wire.
 
I had simply speakers do the refoam

Yes it costs more , you have to send them the speakers.BUT they did a terrific
job. Their return packing was amazing. That was in 1979 and my woofers are still performing like they are new.:banana::banana::banana:
 
Go with the battery!!! I just did my first refoam a while back. The woofers in my RS4000's had the hocky pucks on them and I couldn't shim them. I found a post about useing a battery and went that way. Best way as far as I'm concerned. I used a "c" cell and enginered a battery box out of cardboard, and couple of feet of speaker wire with alagator clips on the ends. Hook the battery up to the speaker and watch the movement, one way will move it up, the other down. I hooked the bat. up in the up position and spread the adhesive on the edge, leave the bat. hooked up, install the foam and let the adhesive dry. With the coil in the up position you can apply your adhesive to the frame/gasket then when ready reverse the bat. polarity and it will hold the voice coil centered and press the foam down. Use light presure at 12, 3, 6, and 9 oclock to secure the foam then lightly press it the rest of the way arround to finish. With the bat holding it centered you can't hardly go wrong.
 
krimney said:
I've done dozens of speakers, including 12" infinity and have only shimmed on one occasion(not the infinity). I glue the surround to the cone and let it dry. then I use big paper clamps to secure the surround to the basket, make sure I have travel in and out , and then remove one clamp at a time and glue. repalce the clamp and move on to the next until all is glued. i sometimes use a battery to help center but not usually.

I think the item of biggest importance when re-foaming is the glue. You want it to set up fast enough so that things don't move around, but not so fast as you have no time to work.
Click to expand...

as Sir Byrd said....this
 
I used a test tone CD to align the the cones on my QLS1s, it came with the kit, All I had to do was set the woofer on the floor magnet down, let the glue get tacky on the basket, the test tone aligned the VC and I clamped it in place. These were my first refoam job and saved me some money, plus learned a thing or two, Good luck with your Kappas.
 
rutro said:
I hooked the bat. up in the up position and spread the adhesive on the edge, leave the bat. hooked up, install the foam and let the adhesive dry.
Click to expand...

Electrically aligning the VC is a very good way.
However,I would not leave any DC power supply hooked up directly to any driver.

I am surprised that your drivers in the RS4000's are still alive!
A quick on/off for a polarity check would be as far as the battery check/test would go with me.
VC's dont like DC.

Would this method work:-
Connecting the driver to an amp with nothing being played.
The amp simply being on,should align the VC!
 
Choices, Choices , Choices

I don't know and I am not even sure what a refoam kit goes for, but around here ( Boston ) there are a number of speaker repair places. A 12 woofer costs $25.00 to refoam and they do the dustcap as well. Seems pretty cheap to have it done by a pro and not have to worry....though it does not seem all that difficult and I would love to learn how to do it myself. By the way the original kappa dustcaps are foam covered cloth with no logo...I think I saw Infinity logo dustcaps on the bay for sale pretty cheap....... I think I like the logo better.
I wouldn't put them on my 9's though because I am so anal I would want all the logo's to line up perfectly and that looks like a PITA......
 
You can always make your own shims bu using those plastic label holders that are used on those hanging green file folders. I've done that plenty of times and it works like a champ. ust cut them down for the size and lengths you need and you are good to go. Other than that, I use the battery or the 30Hz tone method.
 
We are the pros!! The pros from Dover........


The 4000's are very much alive and thumping, the weak 1.5v. force from a single "c'' cell couldn't hurt the coil in those woofers. The adhesive in the kit I got is a Devcon Contact Cement that drys fairly quickly. It's a 5min till tacky and you only put it on one surface, and not the foam. It drys flexable and clear. I used a small paint brush and it cleaned up well with Zylol. The prep on the cone and frame takes longer than the actual repair. My little sis could do it.........:D
 
Augy said:
I don't know and I am not even sure what a refoam kit goes for, but around here ( Boston ) there are a number of speaker repair places. A 12 woofer costs $25.00 to refoam and they do the dustcap as well. Seems pretty cheap to have it done by a pro and not have to worry....though it does not seem all that difficult and I would love to learn how to do it myself. By the way the original kappa dustcaps are foam covered cloth with no logo...I think I saw Infinity logo dustcaps on the bay for sale pretty cheap....... I think I like the logo better.
I wouldn't put them on my 9's though because I am so anal I would want all the logo's to line up perfectly and that looks like a PITA......
Click to expand...

I bought those! Thought it would look nice.
 
I had this idea when people told me the 60 hz hum from a bad ground wont hurt the speakers. What about using a step down transformer - which I got lying around by the dozen and the ac. Well, I probably would use a current limiter, heck an old ac adapter probably has 4-5 volts and maybe 1/2 amp. Using one of those.
Cool.
Srinath.
 
You must log in or register to reply here.
Back
Top Bottom