Repanelling ML Clarity's

MartinLogan Audio Owners Forum

Help Support MartinLogan Audio Owners Forum:

neil5m

Well-known member
Joined
Jun 22, 2015
Messages
83
Reaction score
0
Location
Hong Kong
Neil, did you try to contact MJ Dijkstra via diyaudio?
Hi Tosh, sorry missed your message. Yes I tried contacting him on the diyAudio site. When my current coating quits, I'll try MJ's coating. So far the RB-048 coating is doing well. Am happy.
 

surfatwork

New member
Joined
Jan 1, 2022
Messages
4
Reaction score
0
Hi Neil (and others),
Thks for sharing your trials with the coatings. I have a pair of ML ESLs with the familiar problem - drop in HF volumes. Tried the showering/washing trick, but it didnt improve matters. So decided to re-coat the film - procured a bottle of Licron (which is all I could get here in India).
- How does one open the stators? They seem to be quite firmly glued together. Any tips would be much appreciated
- Do you have to spray the Licron on both sides of the mylar film?
- does the diaphragm lose tension if/when I open the stators? Or will it still be affixed to the sides (of what I dont know)
- will I need to reattach the HT wire if I pull these apart?

I am in a slightly remote part of India, so getting parts takes time. Just trying to gather what I need before starting the operation. I've got kapton tape and the spray. Anything else I am likely to need? I do have general electronic diy stuff (like a soldering iron etc.)

thanks very much. Look forward to the replies before I start pulling them apart.
 

Robert D

Well-known member
Joined
Jul 21, 2020
Messages
1,097
Reaction score
221
Hi Neil (and others),
Thks for sharing your trials with the coatings. I have a pair of ML ESLs with the familiar problem - drop in HF volumes. Tried the showering/washing trick, but it didnt improve matters. So decided to re-coat the film - procured a bottle of Licron (which is all I could get here in India).
- How does one open the stators? They seem to be quite firmly glued together. Any tips would be much appreciated
- Do you have to spray the Licron on both sides of the mylar film?
- does the diaphragm lose tension if/when I open the stators? Or will it still be affixed to the sides (of what I dont know)
- will I need to reattach the HT wire if I pull these apart?

I am in a slightly remote part of India, so getting parts takes time. Just trying to gather what I need before starting the operation. I've got kapton tape and the spray. Anything else I am likely to need? I do have general electronic diy stuff (like a soldering iron etc.)

thanks very much. Look forward to the replies before I start pulling them apart.
I was going to pay a guy in northern Ohio to recoat mine for me but after seeing how strongly the panels were attached to each other he told me he didn't want to do it. He figured chances are he'd tear the membrane when separating them. He is highly experienced doing the job too. Many use him.

I ended up buying new Prodigy panels instead.
 

slofut

Active member
Joined
Jun 21, 2021
Messages
34
Reaction score
4
Location
SW GA, USA
Icr, has anyone used ER Audio for supplies to recoat or replace panels? I got a quick email reply from Ron and their methods seem fairly proven. I like that they recommend modifying the charge strip to go down both sides. Abt 70 bucks for film and everything I think? Very reasonable risk.

 

Stevieg335i

Member
Joined
Mar 24, 2018
Messages
6
Reaction score
4
Location
Weymouth, Dorset Uk
Hi,

Yeah I’ve used ER Audio for a couple of years, since my SL3 panels failed. They are a great company, their products are good and they are extremely knowledgable and helpful.

@surfatwork. Taking the panels apart is not easy. As previously said they are very well glued together with 3M double sided tape. There is a very good chance that you will tear the film. If that happens then the panels will need to be completely rebuilt.

The way I separated the panels was to run a strong knife along the bottom edges of the panel. Don’t go too deep! Then soaked each end of the stator in acetone. I put the acetone into a washing up bowl about three inches deep and left one end of the panel in the bowl after propping it up. I left it for a few hours on each end. Then I used the knife again to cut some of the softened tape. Then I used some strong tools (like small pry bars) and eventually got the end apart. I did manage to get one panel apart intact, but on the second one I tore the Mylar, so I ended up have to rebuild them from scratch.

If your panels have black spars then it is likely that they are made from a 3M VHB double sided tape and could be glued to both the front stator and the Mylar. If so this will make it even less likely you will be able to split them without tearing or stretching the film.

The later panels have clear spars which are made from something like petg (like mine were), but they still may be glued on both sides.

So it can be done but it’s not for the faint hearted. Good luck if you decide to go for it.

I currently have my original pair of SL3’s, another pair that someone gave to me (one panel is arcing like mad) and a pair of Aeons where panels are completely gone. So I’ll be rebuilding all six panels when the weather warms up a little. Keep me occupied anyway lol.

Kind regards

Steve
 

slofut

Active member
Joined
Jun 21, 2021
Messages
34
Reaction score
4
Location
SW GA, USA
Thanks for the help Steve,
I told myself when i got these speakers i wouldnt let it turn into another project, hoping it was an electrical issue. But they look so nice i have a hard time just letting them sit in the closet broken.
Since these are very early models, i suspect the spars will be vhb and im looking at a complete rebuild. I take it ER has spar material? Since tolerances are so close i dont want to get into reinventing these things with juggling thickness and spacings. Any advice?
 

Stevieg335i

Member
Joined
Mar 24, 2018
Messages
6
Reaction score
4
Location
Weymouth, Dorset Uk
Hi,

As far as I know ER Audio won't have suitable spar material for the ML's.

If your spars are black and you wish to use the same material then you want 3M 4990 VHB doube sided tape (1.1mm thick) 6mm wide for the rear spars and 3M 4929 VHB double sided tape (0.6mm thick) for the front ones. I don't know where in the world you are but it was almost impossible to get in the UK, I was looking at getting it shipped over from the US. However the spars were clear on my panels and after talking with ML support I decided to use acrylic / petg sheet (1mm and 0.5mm thickness and cut the individual spars. I then used very thin VHB tape to attach the spars to the stators. The tape I used was 0.2mm thick so it brought the thickness of the spars pretty close to the original ones.

One of the pair of SL3's I was given is working really well, it has black spars on it. I have it connected to my hi fi along with one of my repaired ones and the there is no difference in sound quality but the volume is very slightly less.on my repaired one ( about 1db) . However I noticed that the HV output was out of spec (supposed to be 2100v +/- 5% for the SL3) so I will have to sort that out before doing any real comparisons.

Have you checked your speakers to make sure the HV voltage is in spec? If they aren't then you could get lower output from the panel....Just a thought.

HTH

Steve
 

slofut

Active member
Joined
Jun 21, 2021
Messages
34
Reaction score
4
Location
SW GA, USA
Steve I'm in the USA, SW Ga. If I have to replace the mylar I'd rather have the option of removing the front stators to clean etc... So I guess I'll be looking at the acrylic sheet method. Does no one make thin acrylic on a roll in the correct dimensions? I'll bet that's a lot to ask, and in the grand scheme, cutting spars out of a sheet isn't much of a concern. Are there any longitudinal pieces to bond to the stators or just the horizontal spars? The acrylic sheet you got, was it clear like your original spars or black? Also, if it was clear I guess the thin .2mm vhb was prob black anyway? I actually just checked for hi voltage, but didn't note exactly what voltage so I'll go back over this. The panels look so good I don't want to take them apart if I don't have to so I intend on a full troubleshoot and assessment before going much further. I just need to find a couple hours 🙂
 

Stevieg335i

Member
Joined
Mar 24, 2018
Messages
6
Reaction score
4
Location
Weymouth, Dorset Uk
Hi,

If the HV is around 2100 - 2200v then I would have thought that this was in spec on your speakers. ML told me that it it would take a difference of a few hundred volts to appreciably alter the balance. I would have thought it unlkely that both your speakers were suffering from a large drop in HV voltage but you never know and as you say you need to check it.

As you're in the US You should be able to get hold of the black VHB tape easily enough. That is the tape that ML used to use before going to the clear spars. The 0.2mm tape I used was also clear. I do not know how ML make their spars but its not too much hassle to make your own from acrylic sheet. I wanted the spars to be the same as my original panels so it was clear acrylic that I used. More difficult (at least for me anyway), was getting the spars attached to the stators perfectly straight so that the front and rear spars line up when the stators are put together. Be easy enough if the statos were flat but not so easy when they are curved.

If your panels are constructed the same way as mine then the rear stator (that the mylar attaches to) has vhb tape both on the ends (assuming it wasn't destroyed when the panels were split) and along the vertical sides. On my panels, only the ends were glued together with tape, the vertical sides were not. Assuming that you have to replace the mylar and if you want to keep the tape you will need to thoroughly clean the old mylar from it all the way around the stator. Imho I don't think that using the old tape is satisfactory, After the mylar has been removed it is not exactly in great condition. You could replace the tape (time consuming but not that hard to do) but after trying it once I won't do it again!. The problem is that if you use VHB tape then when you come to attach the mylar to the rear stator, you only have once chance to get it absolutely right. If there are creases in the mylar after it touches the tape then you either live with it (not good) or you start again.

The way I am going to do it when I rebuild the panels is to remove all the tape from the rear stator. I have bought a couple of sheets of petg and will cut them to size to fit around the stator. I found some sheets that were the right thickness (~1.1mm) and will glue them to the stator which, in my case is 122cm in length. I did not want to have to join strips of petg together so I bought sheets that were over 122cm in length. Hope that makes sense. I will glue them to the stator giving me (hopefully) a nice face to bond the mylar to. Incidentally when you get to bonding the mylar to whichever surface you decide on, use polyurethane glue ( I use the one from ER Audio). It gives you a little time to make sure that the mylar is flat and not creased. Also a lot of glues do not bond well to mylar.

Hopefully this gives you an idea about how they are constructed and how to rebuild them if you decide to go that route. It is a lot of time and effort (we haven't talked about jigs yet) but, to me anyway, absolutely worth it.

HTH

Steve
 

surfatwork

New member
Joined
Jan 1, 2022
Messages
4
Reaction score
0
So I finally bit the bullet and decided to wade into my ESLs. Managed to get my hands on some MEK, so had high hopes. Sadly, it has ended in failure, with a torn diaphragm.
Looking at it again, I think it is pretty much impossible to separate the stators without damaging the film. The order is back stator->white double sided tape->film->black double sided tape->front stator. The struts are also glued to both the film and the nearest stator (front or back).
So unless, one miraculously manages to peel off ONLY the black tape from the front stator, without getting in between the black and white tapes, and then manages to peel off the stator from the struts, tearing the film is guaranteed.
Sadly, I don't think I possess that level of dexterity and luck. Just sharing for future reference.
I don't know how other MLs are constructed, but it looks like they really didn't want anyone opening this one up for repair.

The good news is that MEK does work very well. Wear gloves and work in a very well ventilated area. I found it best to soak it for a while first (just a few mins) - I used a syringe to direct the MEK.
After that, squirt some more MEK into a few inches of tape and immediately cut it with a credit card or similar. then squirt the next stretch, cut and so on.

Figuring out what to do for a replacement diaphragm. Mylar isn't easily available here, atleast in retail quantities. MOQs seem to be of the order of 1000 sq m!!
 
Top