I've been talking about this in the Apogee thread, and a diligent member reminded me we are getting off track, thank you, so here I go on a proper one.
I decided to re-mylar the CLS I have and have a question. People say one failure is the charge ring as all they did was wrap the bias wire around the aluminum charge ring strip. Mine didn't go bad for this reason, just age. I was thinking of using a 18 or 20 ga copper wire that I can solder the bias wire to. It also would protrude a little higher ensuring good contact with the membrane coating. What do you people think, any flaws with this idea?
Here are my freshly covered panels. I'll post photos of my simple yet effective mylar installation jig later that helped me do a perfect covering without wrinkles.
I decided to re-mylar the CLS I have and have a question. People say one failure is the charge ring as all they did was wrap the bias wire around the aluminum charge ring strip. Mine didn't go bad for this reason, just age. I was thinking of using a 18 or 20 ga copper wire that I can solder the bias wire to. It also would protrude a little higher ensuring good contact with the membrane coating. What do you people think, any flaws with this idea?
Here are my freshly covered panels. I'll post photos of my simple yet effective mylar installation jig later that helped me do a perfect covering without wrinkles.
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Ha! Looks great! I think a wire bias ring around teh entire panel (not just sides and bottom) would be just fine. Have you decided what you will use for coating? What tension did you end up using?
I was gonna start on mine this weekend and got busy with other crap.
Let's see some jig pics!
I was gonna start on mine this weekend and got busy with other crap.
Let's see some jig pics!
Not knowing how much to tension it to, I used 5 pounds of pull lengthwise and 2 sideways. That seems to eliminate all wrinkles before adhering it to the stators.
I already got the foil material for the ring, but I like the idea of the copper wire. I think there is a better chance of full contact all the way around where as the foil is pretty thin and even any waves in the foam or stator could make it not touch 100%, not that it may really matter (?)
I order some Elvamide a few weeks ago, but then found a can of Licron Crystal ( another member found me some) so it should hopefully be here tomorrow. From what everyone says, the Licron seems to be the way to go so that's where I'm headed.
Once they are ready to bond, I think I'll clamp them together temporarily to do a test run to make sure all is well
I already got the foil material for the ring, but I like the idea of the copper wire. I think there is a better chance of full contact all the way around where as the foil is pretty thin and even any waves in the foam or stator could make it not touch 100%, not that it may really matter (?)
I order some Elvamide a few weeks ago, but then found a can of Licron Crystal ( another member found me some) so it should hopefully be here tomorrow. From what everyone says, the Licron seems to be the way to go so that's where I'm headed.
Once they are ready to bond, I think I'll clamp them together temporarily to do a test run to make sure all is well
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Cool, let us know how it works out. I will plan my CLS Mylar "Makeover" soon.
Many thought the opening and re-mylaring the CLS was impossible. Bah!
Many thought the opening and re-mylaring the CLS was impossible. Bah!
I imagine this <possibly> leading to high stress in the diaphragm at the points where it contacts the wire? But that probably depends on what material you're using for spacers -- double-sided foam should be compliant enough, but something harder might not? Good luck!
You might call up Russ at justrealmusic for a chat...
My thoughts exactly, I'm using foam tape all around and i'll dress the ends of the copper wire so nothing will damage the Mylar
The Double Sided tape can compress a bit and I think it will be fine. I plan the same with 15AWG bare wire loop.
If I can just get some time to start the re-mylar project....
If I can just get some time to start the re-mylar project....
If you purchase copper foil tape with conductive adhesive you can stick it directly to the coating on the diaphragm rather than relying on pressure contact from the opposing foam spacer.
Another great thing about the copper foil tape is the wire lead from the bias supply can be soldered to it; making a never-fail contact. The photos below show this. However, I would follow Bolserst's advice and use the type foil with conductive adhesive, and stick it directly to the diaphragm (rather than to the opposite stator as shown in my photos):
A couple steps closer
The stretching rack I made to stretch the Mylar. I stretched it 1.5%. I used a wooden curtain rod as the roller and made a crank for it. There's a good YouTube video of the Logan factory installing the membrane on a curved panel, and they stretch it lengthwise, but very little to none sideways. I would have done this in the garage, but it's pouring rain and I didn't want to take a chance with the added humidity today.
Rack on the panel, which I made a curved support for to hold it
Finished panels. I found a can of Licron Crystal so tomorrow I spray...if it quits raining.
The stretching rack I made to stretch the Mylar. I stretched it 1.5%. I used a wooden curtain rod as the roller and made a crank for it. There's a good YouTube video of the Logan factory installing the membrane on a curved panel, and they stretch it lengthwise, but very little to none sideways. I would have done this in the garage, but it's pouring rain and I didn't want to take a chance with the added humidity today.
Rack on the panel, which I made a curved support for to hold it
Finished panels. I found a can of Licron Crystal so tomorrow I spray...if it quits raining.
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I've read your blog 20 times if I've read it once. That in itself is a masterpiece! You've helped me a lot along the way, thank you!
I haven't completely decided on the charge ring. Here in 100k population town in Canada, I'm amazed how difficult some items are to get. We have a decent industrial electronics store, but to get that Licron or conductive tape is next to impossible.
I'll check around some more and see what I can find, otherwise I think I'll run an 18ga copper wire around the perimeter and solder the lead to it.
Your jig was a lot like I had planned, except for the curtain rod and crank. I was going to use my two kids and a fish scale. Your method looks a lot more elegant, and more likely not to get chocolate stains all over the mylar 🙂
I am going to try the Sodium Laurate hand soap and clamp it all together and see what it sounds like on a fresh mylar...hopefully next weekend.
Also very important is the little flash Neon Light bias circuit to tell you how quickly the panel requires a recharge. A steady fast flash indicates the panel has a leak somewhere, and is having a hard time holding the bias voltage. It will not put out the required SPL with a leak, and may damage your amp if too low..
I am going to try the Sodium Laurate hand soap and clamp it all together and see what it sounds like on a fresh mylar...hopefully next weekend.
Also very important is the little flash Neon Light bias circuit to tell you how quickly the panel requires a recharge. A steady fast flash indicates the panel has a leak somewhere, and is having a hard time holding the bias voltage. It will not put out the required SPL with a leak, and may damage your amp if too low..
I have a question with the Licron, do I need to clean the Mylar with alcohol or anything before I apply it?
Yes Do clean the Mylar!!
Even with the old licron, I have had finger print images left from the coating not adhering to.
You won't be able to see this with the Crystal formula.
I use Denatured alcohol, If acetone gets on to your sticky tape it may melt the tape a bit and cause a weakening of your bond.
jer 🙂
Even with the old licron, I have had finger print images left from the coating not adhering to.
You won't be able to see this with the Crystal formula.
I use Denatured alcohol, If acetone gets on to your sticky tape it may melt the tape a bit and cause a weakening of your bond.
jer 🙂
Yes, I have the newer stuff. It went on totally clear. I know the perils of Acetone and other thinners having worked in auto body some years ago. Tomorrow I'll put them back together and take them for a spin around the block...so to speak.
The double sided tape used around the perimeter will keep a constant tension for the long haul?
I can see it used on sides as very little tension is needed because of the curve.
Will you be gluing the final stator top and bottom sections to keep it from moving over time?
Regards
David
I can see it used on sides as very little tension is needed because of the curve.
Will you be gluing the final stator top and bottom sections to keep it from moving over time?
Regards
David
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