Brake fluid and LansaLoy

[boputnam]

Hey, Earl...

Rather than pm this, I thought I'd encourage the dialogue continue, and Link-in an old Thread, too.

I've a pair of LE14A's that are virgin, and have the thick, original and now very rock-hard Lans-a-Loy surround (front mounted). The surrounds are cracked, and would seem well beyond the DOT3 Lans-a-Loy treatment. But, would the DOT3 facilitate surround removal? I don't want DOT3 to soak into the cone, and will otherwise just do the careful/tedious trimming away.

Advice? Thanks!

2235 Break in Time (see p2) - Link

[Earl K]

Hi Bo

My experience with the DOT 3 brake fluid is that it's virtually impossible to not discolor the white cone somewhere. No matter how carefully applied & how sparingly - I think it's just a matter of time. My last rehab ( early this summer ) had this problem when fluid "leached" from the back of the surround to the cone. This seems to have been caused by the fact that this unit had - or had a new Lans-a-Loy surround installed at some point. The glue-joint between the cone & surround wasn't perfect in 2 spots allowing easy migration.

That said ; the fluid will make the surround easier to remove. If you do remove the surround - consider putting in a new spider for a full rehab. I haven't done this myself so I'm just talking through my hat a bit here. You'd need to cut around the cone in the surround and the slice around the spider. Once desoldered from the binding posts you'd need to remove the old spider and dustcap with some carefully applied ( & ventilated ) MEK .

One of my more successful rehabs started with a surround that was split all around in 2 separate concentric rings ( top of curl & bottom of curl ). This surround was hanging in by only a thread ( here & there ). Dot 3 softened up
the surround and when Fs reached sub 20 hz I started "reskinning" the cracks with very thinly applied GE Silicone caulking compound. The silicone was continuously smoothed down to a Gloss-like finish with a wetted finger of more DOT 3 . Hopefully this stuff isn't poisonous - but I don't know that. This unit maintains an Fs of about 26hz ( last measured this summer ) .
Now its companion le14 is a different story. That unit had no splits in the surround. I followed the above mentioned procedure and installed smoothed down Silicone but slightly thicker. This unit's silicone finally cured about 3 months later and the Fs shot up to @ 120 hz ( like cardboard ).

So working with brake fluid iis easy - working with Silicone for any reskinning attempts is a dicey affair.

Rehabbing has some other pluses - the Zmax at Fs of these surrounds is lower by quite a lot - the curve looks like conjugate damping resistors have been added to a crossover network . FWIW . & maybe that's more important to Tube-type guys - I don't know.

regards < .Earl K

[Mr. Widget]

Hey Bo,

How bad is the cracking? I have had good results using a special CA glue to repair small cracks along with the DOT 3 application.

[boputnam]

Thanks, Earl!

And, Mr. Widget, welcome back to the mainland

Here's some pics - HARD as a rock (and them, I DO know...)

[boputnam]

and...

These are beauties, but man-oh-man - that cone will barely move by gentle hand pressure. Whoa...

[Mr. Widget]

I would try the DOT 3 very sparingly and then evaluate whether you want to re-foam them. Once the Lans-a-loy is softened up a bit, overnight, you can check the extent of the cracking better. I would heed Earl's caution about staining and not put any fluid near the cone.

If they still need re-edging then they will be easier to work with.

[Earl K]

Hi Bo

Real nice. I'd really endeavour to save those surrounds. I use a small artists bristle-hair type paint brush for the application of the DOT 3. Apply front & back over the course of a few days. The fluid does eventually cause small fissures or tiny ruptures in the LansaLoy material as it swells beyond its' capacity to absorb the fluid.

regards <>Earl K

[boputnam]

Originally posted by Earl K
I'd really endeavour to save those surrounds.

OK, will do. Mighty glad I asked. However, my wifey, already knowing I'm goofy, will now know I gone nutters, as well...

The fluid does eventually cause small fissures or tiny ruptures in the LansaLoy material as it swells beyond its' capacity to absorb the fluid.

That confuses a bit - is there any risk these fissures/ruptures will penetrate/breach the surround?

And, I read somewhere, Earl, you noted this is not permanent, and needs some maintenance. For the Thread, can you repeat the Dr. Lans-a-Loy Advice on the periodicity of DOT 3 application?

Lastly, why is the Lans-a-Loy more preferred than a new foam surround? Because of the lowered Zmax? Anything else?

Thanks.

[boputnam]

Hey, Earl...

I'm gonna pile-on my own post here, in-case you come back with the above answers, could you maybe expand into...

1) how can a fluid (DOT3) seeping into pore space result in a pliancy similar to the original? Fluids are not compressible, and heavier than "air" (as was in the original spongy lansaloy), so the DOT3-lansaloy product would seem very different, indeed. It may be pliable, but very different from original, no?

2a) if lansaloy is a preferred surround material, why did JBL discontinue it? I'm wondering if it is because it has/had a tendency to rather rapidly dry-out and become less pliant, changing/denegrating the Fs...?

2b) why are the new recone kits for the LE14A's fitted with foam surrounds (I just got some that were reconed - nice! ).

You (and Widget, it seems...) have done the work on finding the DOT3 salve, and I thought maybe you've got more background on this.

[Earl K]

Hi Bo

I'll address your posted questions in some detail this evening.
Right now, I'm going hunting/shopping for ( you guessed it ) more surplus capacitors.

( I'll try to take a closeup of that latest le14a and it's "fissured" surround )

BTW: How do you get such great closeups - a special lense or something ?

<. Earl K

[boputnam]

Hey, Earl...

Cool - looking forward to your thoughts. Good luck on the hunting!

The camera is the Olympus C-5050 Zoom, 5.0 Mpxl, using the macro-focus setting, handheld, no flash. Fast lens, and approx. 400 ASA.

Olympus C-5050 Zoom - Link

I'm a long-time Nikon man, myself, but have semi-retired the FM2 body in lieu of this bad little boy. The C-5050 "dog can really hunt", and with those nifty little removeable chip-cards, I've quit buying film.

Full disclosure: I bought my wifey one - the C-3030, I think, about three-years ago - and then when we went to Iceland on a geologic excursion we had a click-off: side-by-side shots from each. I have to admit, the Olympus, even the then 3.2 Mpxl beat the FM2 in most instances. The fill-flash added just when needed, and the overall quality was as-good-if-not-better than the FM2 (fast film, medium-fast lens). So, about 8-mos ago I moved-up to the 5.0 Mpxl, which is simply better for what I use the box for, but I dearly miss the "art" of the SLR.

[Mr. Widget]

Hi Bo,

I wouldn't claim that Lans-a-loy is superior, I doubt that there is much functional difference between foam or Lans-a-loy if you made a comparison of both surrounds when new. I simply advocate Lans-a-loy rejuvenation as it is fairly simple, very inexpensive, and it maintains the value of the driver in the collector market. (As one who is frequently trying different drivers, I like to do what I can to keep the highest resale value for the inevitable future sale.)

If you are trying to maximize performance, I am afraid I would have to agree with Giskard and recommend a complete recone as a driver of this vintage will have a tired spider as well. (Remember the improvement of the 2421 with it's new diaphragm?)

While I am not one who likes to make compromises, I think the $1.50 investment in brake fluid is worth trying. If you are happy with the results... great!... if not, then there is the next half step, the resurround, or the whole enchilada, the complete recone at over $180 each.

Concerning those later appearing fissures that Earl mentioned, I haven't had that experience. I have found additional tiny cracks after softening up of the surround, but I believe this is due to them being masked while the surround was stiff.


BTW I have a bottle of DOT-3 and a brush on my work bench if you want to borrow them.

[Earl K]

Hi Bo

That confuses a bit - is there any risk these fissures/ruptures will penetrate/breach the surround?

- I've never seen it happen.

And, I read somewhere, Earl, you noted this is not permanent, and needs some maintenance. For the Thread, can you repeat the Dr. Lans-a-Loy Advice on the periodicity of DOT 3 application?


- Well , it seems the DOT 3 eventually will also dry out. Now, I've only been at this for a year so I don't have a handle on , how fast & how much - but DOT 3 works & is cheap !!!

Lastly, why is the Lans-a-Loy more preferred than a new foam surround? Because of the lowered Zmax? Anything else?


- Well, I just about always take the path of least resistance - so that's my excuse. I have/did notice and measure that the Zmax is different /lower - plus it's Q is also lower ( wider skirts ). But I have as yet to meet anybody who figures this is very relevant to their audio happiness .

1) how can a fluid (DOT3) seeping into pore space result in a pliancy similar to the original? Fluids are not compressible, and heavier than "air" (as was in the original spongy lansaloy), so the DOT3-lansaloy product would seem very different, indeed. It may be pliable, but very different from original, no?


- I do think it is different than the original

2a) if lansaloy is a preferred surround material, why did JBL discontinue it? I'm wondering if it is because it has/had a tendency to rather rapidly dry-out and become less pliant, changing/denegrating the Fs...?


- Apparently JBL discontinued it because this recipe for foam rubber dried out too fast and they were replacing "free of charge" the dried up surrounds. They had to "cut bait and run". They aren't a charity . LOL .

2b) why are the new recone kits for the LE14A's fitted with foam surrounds (I just got some that were reconed - nice! ).


- I keep my surrounds original because I can - no other real reason. I'm with Mr Widget here - it's not a functional superiority issue -it's more the fact that in less than 4 days I can rehab my woofers without them leaving the house.

regards <> Earl K

I'll post some pics tomorrow of the small fissures I'm talking about. They are small and actually more resemble a mottling effect in the skin of an orange or an octogenarian

[boputnam]

Hey, Earl...

Thanks for taking the time to do that.

[Earl K]

Hi Bo

Here's the pic of le14 #7 with its fissured surround . BTW, this isn't seeable until one is within 2 feet.

Oh, I forgot to mention the main reason I like the Brake Fluid rehab is that I like to determine what the speakers Fs is going to be. I prefer low 20s with 23 or 24 hz being a real nice usable number . Refoaming gives you no choice . And so far, no one has reported back ( or I forgot ) what that Fs number is after refoaming an le14a. I suspect it approaches 30 hz..

regards <> Earl K