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gasfan
01-06-2016, 12:15 PM
So here are the before and after shots of my 2203Hs I thought were shot. Seriously collapsed spiders. I got in touch with Ken who informed me the only real remedy is to replace them along with the caps; removal of the mass rings, etc. So I thought I may as well give it a try...support the cones and dab acetone on the spiders. I did this 3 times, letting them dry and checking in between by removing the support. Close but no cigar. 2 more times using a blow dryer on high to dry them. Success! It worked perfectly. The cone doesn't pop back and forth past center as a stretched spider would indicate. They did so before. They are now nice and bouncy, slight collapse of the spiders in either direction from the weight of the cone(no foams installed). I'm ecstatic to say the least:)

Earl K
01-06-2016, 04:41 PM
Nice Save on those spiders !

As a heads-up ( since you appear to be into this sort of transducer finagling ).

Canadian Tire ( at least here in North Toronto ) currently sells MEK ( Methyl-Ethyl-Ketone ) (http://www.canadiantire.ca/en/pdp/mek-946-ml-0475884p.html#.Vo2vW7YrI1I).
- This solvent had been ( for the longest time ) extremely hard to get ( here in Canada ) .
- Reconers use it for some very specific jobs on the bench ( since it's stronger than Acetone, as well as being a better solvent for some of the glues used by JBL ).

Anyways, I suspect this product is about to disappear from the retail market ( likely by years end is my guess ) due to it's highly aromatic nature ( & expected new Cdn rules coming out of the recent Paris Accord on Climate Change ).


So, Stock-Up ! while you can ( if you care ) .

:)

NickH
01-06-2016, 04:49 PM
Just don't keep mek around on the shelf for many years. It turns into acetic acid with time.


Nick

Earl K
01-06-2016, 05:04 PM
MEK facts on worldwide consumption (https://www.ihs.com/products/methyl-ethyl-ketone-chemical-economics-handbook.html)

MEK, chemical "breakdown" pathway (http://eawag-bbd.ethz.ch/mek/mek_map.html)

:)

gasfan
01-06-2016, 05:27 PM
Nice Save on those spiders !

As a heads-up ( since you appear to be into this sort of transducer finagling ).

Canadian Tire ( at least here in North Toronto ) currently sells MEK ( Methyl-Ethyl-Ketone ) (http://www.canadiantire.ca/en/pdp/mek-946-ml-0475884p.html#.Vo2vW7YrI1I).
- This solvent had been ( for the longest time ) extremely hard to get ( here in Canada ) .
- Reconers use it for some very specific jobs on the bench ( since it's stronger than Acetone, as well as being a better solvent for some of the glues used by JBL ).

Anyways, I suspect this product is about to disappear from the retail market ( likely by years end is my guess ) due to it's highly aromatic nature ( & expected new Cdn rules coming out of the recent Paris Accord on Climate Change ).


So, Stock-Up ! while you can ( if you care ) .

:)

Thank you Earl. I may go get some stock but not sure I'd want to use it for this purpose since it took multiple applications. I think a more gradual result is safer, ie: more predictable? Hard to say but fast effect may result in the assembly falling apart? I have good experience with acetone. Mind you this is my first attempt with collapsed spiders.

Earl K
01-06-2016, 07:37 PM
Thank you Earl. I may go get some stock but not sure I'd want to use it for this purpose since it took multiple applications. I think a more gradual result is safer, ie: more predictable? Hard to say but fast effect may result in the assembly falling apart? I have good experience with acetone. Mind you this is my first attempt with collapsed spiders.

In case there's a language barrier at play here.

I wasn't suggesting that you use MEK instead of Acetone for spider reforming . I too would use Acetone to attempt what you just did.

I suggested owning some MEK so that you have it on hand for other types of speaker jobs (ie; dismantling/cleaning & rebuilding transducers /// you might ask Ken what he typically uses MEK for ).

:)

gasfan
01-06-2016, 07:58 PM
Oh, right. Sorry, I did think you were. I have heard it said that language is the greatest barrier to communication:)

Ed Zeppeli
01-06-2016, 09:15 PM
My JBL re-coner used to dilute the JBL glue with MEK and put it in a syringe for doing nice lines around the dustcap.

Wagner
01-07-2016, 09:04 AM
MEK facts on worldwide consumption (https://www.ihs.com/products/methyl-ethyl-ketone-chemical-economics-handbook.html)

MEK, chemical "breakdown" pathway (http://eawag-bbd.ethz.ch/mek/mek_map.html)

:)
Nice
Production: UP
Quality questionable (chinese)
More of it will be an IMPORT into the U.S.A., if at all
More Regulations (thanks libtards)
Price: UP

I bought a gallon about a year ago (here in Northern Kalifornia)
At that time (and still), was easier to find locally than 99% pure isopropyl alchohol (not kidding or exaggerating)

I always found it "funny" when certain nitrocellulose products and rubbing oils were being pulled from the shelves of my local ACE and yet I could still easily buy a 5 gallon bucket of MEK or lacquer thinner at the same store (all thanks to the bull shit Kalifornia CARB regs)

It's even more funny too; back in the late '70s I spent a brief time working in the fiberglass boat building business. We used a LOT of MEK (it is a catalyst for some resins as well as other uses)

We were required to store it in a semi-bunker type dynamite shed sort of structure due to it's volatility. Fast forward to Kalifornia and I can pull it off a shelf at my local ACE by the bucket and put it in a shopping cart, yet Walgreens wants to see my ID to buy some lighter fluid (Zippo type)

Thank you for posting this as I had no idea MEK was currently under such scrutiny; guess I need to go and verify my supply (no clean re-foam jobs without it!)

Wagner
01-07-2016, 09:16 AM
I wasn't suggesting that you use MEK instead of Acetone for spider reforming . I too would use Acetone to attempt what you just did.
I wouldn't use it (first) at all for the purpose as it is such an aggressive solvent
Always start with the "mildest" option first
In another thread I shared a similar success story using pure isopropyl

Sometimes, MEK will soften or put certain adhesives back in solution and after it evaporates it's as good as it was when it was new (the strength of the bond) Especially with adhesives that used MEK as vehicle!

Other times? Not so much and the old adhesive is severely compromised. You just never know unless you know exactly what was used in the first place

Denatured alcohol also has some excellent restorative properties as well with some old adhesives

I used to be a skeptic as for the strength and efficacy of isopropyl to do certain jobs. Over time, I have learned otherwise (but it does often require more patience but still yielding "just as good as" results in SOME instances) Also less prone to stain and discolor base materials

Regardless, as a result of trial and error over time, I always start with the weakest of the bunch first on the salvage jobs before resorting to the sledgehammer that is MEK

I keep them all on hand

NickH
01-07-2016, 10:58 AM
MEK facts on worldwide consumption (https://www.ihs.com/products/methyl-ethyl-ketone-chemical-economics-handbook.html)

MEK, chemical "breakdown" pathway (http://eawag-bbd.ethz.ch/mek/mek_map.html)

:)


Hmm, thanks for that Earl. I was told it was acetic acid. And I have smelled it in some cans. Now I see its acetate compounds. Which are pretty easily broken down. Smells like acetic too.

Here in Texas its not hard to get. Its still sold in home depot. But there's other solvent not as easy to get carbon tetrachloride is unobtanium. Nasty shtuff. Heard story's about it. Evidently its not recommended to use it and have a beer or two afterwards. Unless you want to die an unpleasant death.

I've always used trichlorethane but not anymore as it is also pretty nasty. But for removing paint and glue there's not much better. Non polar chlorinated solvents are hard to beat for certain tasks.


Nick

Wagner
01-07-2016, 12:26 PM
there's other solvent not as easy to get carbon tetrachloride is unobtanium. Nasty shtuff.
Nick
As for carbon tetrachoride, interesting the philatelist application (and lava lamps!):
https://en.wikipedia.org/wiki/Carbon_tetrachloride#Current_uses

Getting old and can't remember now if it's that or tetrahydrochloride?
Last had some tetrahydrochloride (I think it was) I got from some guys at an old timey TV repair shop back in the late '80s possibly early '90s (the old shop is gone now, torn down to make room for junk stores like "Bed Bath and Beyond" ; - (
It was already banned even then, but the old guys had a big glass jug of it that they cherished.
They gave me/shared an extremely small amount (I bought a second hand TV from them)

Why I wanted it and why they had it was for cleaning controls and pots; stuff made "De-Oxit" look like water by comparison

One drop and all the noise and scratchiness was gone; I've read many old timers lament it's demise

Not 100% though now which was which; just seem to remember "hydro" being in the name? And my little bottle is long gone.

gasfan
01-07-2016, 03:28 PM
I should mention that I'm convinced the cause of the spiders' collapse was due to the foam surrounds contracting/shrinking. They were in apparently good condition, intact and not falling apart at all. But as I pulled the cones upward, I could readily feel quite a lot of tension pushing on them. When I cut them away, that disappeared. Correct foams are usually a little tight before installation so I stretch them a bit sliding them through my fingers a few times until they stay the exact diameter of the cones. However there's no telling what if any environmental factors played a role here. I'm guessing the composition of the foams played the biggest role, whatever that might be.