LE8T-2 refoam quandry

[doyall]

I recently acquired some JBL Aquarius IV’s in very good condition except the Lansaloy surrounds on the LE8T-2’s have, of course, stiffened. Surrounds look perfect, just yellow and stiff. (They even sound right nice.) I thought about trying the brake fluid treatment but from reading other posts the prognosis dictates new surrounds at a minimum. Some trepidation comes from reading that the cones on the LE8T-2 are “light,” “fragile,” “very thin” and “very, VERY, thin.” Although my manual dexterity is acceptable, the last thing I want to have happen is that I ruin a cone, especially as they are quite expensive, if still even obtainable. I could send them out but the cost effectiveness is also questionable and damage could still occur. I also read the recent thread in which Zilch states that Lansaloy surrounds on another model have been successfully removed by a professional using some undisclosed method or substance. Was that method or substance used ever identified? Yet another poster says methylene chloride will dissolve Lansaloy. Anybody got any idea as to what it will do to a paper cone? Also read Rob’s recent post in which the Lansaloy residue was left on the front of the cone and the foam was glued to the rear. Might this work in reverse … leave Lansaloy residue on back of cone and glue the foam surround on the front? Has anybody ever tried leaving the Lansaloy residue on the cone and gluing the foam surround over it? If not, does anyone have any comments on the concept?

Please guide me in the right direction so these transducers do not get ruined.

[edgewound]

Very carefully....and very sparingly soften the Lansalloy surrounds with acetone until they peel off the cone.

Dip an acid brush in the acetone and paint it on the surround...watch the Lansalloy wilt and carefully peel it away.

I hope you people appreciate these tips learned from my 20 years of reconing experience....JBL put me in business.

Is it rocket science? No.

Does it take patience and skill? Yes

A little common sense and lots of practice helps. The LE8 has some pretty tight tolerences, so the margin for error is very slim...close to none.

[speakerdave]

You might get something less critical and less valuable to learn on, like some PR10's.

David

[doyall]

I hope you people appreciate these tips learned from my 20 years of reconing experience....JBL put me in business.

I sincerely appreciate it.

You might get something less critical and less valuable to learn on, like some PR10's.

I have successfully done a pair of 127A's with a gap of .044" and a pair of 305G-1's with a gap of .040" so hopefully the LE8T-2's with a gap of .048" will pose no greater difficulties, except for the cone fragility.

[Robh3606]

Very carefully....and very sparingly soften the Lansalloy surrounds with acetone until they peel off the cone.

Dip an acid brush in the acetone and paint it on the surround...watch the Lansalloy wilt and carefully peel it away.

Hello Edgewound

Thank you for that! I have been wondering how to get the stuff off. Your sharing is greatly appreciated.

I have successfully done a pair of 127A's with a gap of .044" and a pair of 305G-1's with a gap of .040" so hopefully the LE8T-2's with a gap of .048" will pose no greater difficulties, except for the cone fragility.

Hello doyall

The JBL square frame drivers don't give you much wiggle room. You need to get the surround properly centered and installed on the cone. You can't use the play on the outside edge like the round drivers to get you out of trouble if you get it wrong. Just take your time and dry fit the surrounds.

Then you always have the safety net

http://cgi.ebay.com/Vintage-JBL-LE8T...QQcmdZViewItem


Rob

[doyall]

The acetone treatment is not working very well. Either I don't use enough to be effective or I use too much and it bleeds through to stain the cone. That delicate balance appears to be elusive. An other ideas.

[speakerdave]

I did an LE14A yesterday evening. I presoaked the surround with many light coats and then once I had it started I added more to the glued side right at the point of separation while keeping tension on the lansaloy peel. I think what happens with the application of the acetone to the surface of the lansaloy is that it is soaking down to the glue and weakening it. I'm not sure what effect the acetone has on the lansaloy, but it seems to dissolve the glue (?). I'm surprised at that because I thought the glue required methyl ethyl ketone. You can't be in a hurry, because the result will be acetone running down the cone. There is some loss of aquaplus under the glue line; it had apparently interacted with the glue. That will be hidden by the new surround.

I used a flat bristle brush with a metal handle and the big blade in a Swiss army knife which is not very sharp. I poured a small amount of acetone into a small sealable jar and labeled it.

David

[doyall]

If I had known this lansaloy stuff was such a PITA I would have thought seriously about not resurrounding but ... .

Just how much of the lansaloy needs to come off? I have a significant amount of residue remaining on the cone and have much consternation about scraping it any more.