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Old 10th August 2009, 04:25 PM   #171
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Quote:
Originally posted by JonasKarud
Irritating small bubbles? it must be the same as DFP-410!

The conductivity seems to be identical, maybe a tiny bit lower than
DFP-410.

Thanks for sharing.....

Had you ever tried applying it using an artists airbrush?
I may give that a try later this week.
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Old 10th August 2009, 04:39 PM   #172
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Quote:
Originally posted by Few
Thank you for the report. Do you have any sense of how much mass the coating adds to the diaphragm? Licron, for example, seems to build up quite a bit. How does your solution compare?

Few
The undiluted definitely has some measureable buildup...similar to the Licron spray. The diluted mixture had no measureable buildup. Obviously there is some mass added, but I don't have access to a scale that could measure it.
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Old 11th August 2009, 12:59 PM   #173
Few is offline Few  United States
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Thanks very much. Even without a quantitative mass value, knowing that there's no obvious build up is encouraging.

I had the same airbrush idea. That seems promising to me.

Few
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Old 12th August 2009, 11:35 AM   #174
405man is offline 405man  Scotland
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As far as I can tell Quad ESL63 panels have the coating sprayed on and they all look very consistant so airbrushing is probably the way to go

Stuart
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Old 31st August 2009, 09:45 AM   #175
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a good diaphragm coating is to use liquid graphite 33, spray it in a cup add 50% thinner and use a airbrush to spray it on in several layers. mostly 4 to 6 layers will be enough to get slight conductivity. Then use plastik 70 to coat the diaphragm with an isolating coating.


200ml graphite 33 is 12 euro
200ml plastik 70 6,29 euro

enough for loads of panels. Very controlled and uniform coating.
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Old 31st August 2009, 03:31 PM   #176
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Quote:
Originally Posted by justice strike View Post
a good diaphragm coating is to use liquid graphite 33, spray it in a cup add 50% thinner and use a airbrush to spray it on in several layers. mostly 4 to 6 layers will be enough to get slight conductivity. Then use plastik 70 to coat the diaphragm with an isolating coating.
I had experimented with thinning down liquid graphite in the past without much success. It required lots of thinning to get the resistance down to about 1E6. Thinning any further and it didn't conduct at all.

The data sheet for graphite 33 shows the resistivity to be 1000-2000 ohm, or 0.001E6. This is way too conductive for low distortion ESLs...especially when large diaphragm excursions are involved.

What surface resistivity have you measured with 50% thinning?
What is the purpose of adding the plastik 70 coating on top of the graphite? You mention it as an isolating coating, but I'm not sure what you are trying to isolate. What purpose does it serve other than adding undesireable mass to the diaphragm?
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Old 23rd September 2009, 09:56 AM   #177
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I've done some experiments with Prostat DPF-401 and ordinary PVA glue,
and found that a mix of 25% glue and 75% Prostat produced a very tough
high resistance coating in the Gigaohm range.

I presume that the Vermason polish also can be used:

http://uk.farnell.com/vermason/c901/...ive/dp/3026656

It would be nice if anyone on this thread could try this coating mix!
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Old 23rd September 2009, 02:31 PM   #178
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Quote:
Originally Posted by JonasKarud View Post
I've done some experiments with Prostat DPF-401 and ordinary PVA glue,
and found that a mix of 25% glue and 75% Prostat produced a very tough
high resistance coating in the Gigaohm range.

I presume that the Vermason polish also can be used:

http://uk.farnell.com/vermason/c901/...ive/dp/3026656

It would be nice if anyone on this thread could try this coating mix!
Jonas,

Is this a different Prostat coating that is still available?
Or is it the same DFP-410 coating(with some letters transposed ) you mentioned before that is discontinued.
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Old 23rd September 2009, 03:03 PM   #179
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Default Sorry!

Sorry about that, I mean DFP-410.
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Old 23rd September 2009, 03:07 PM   #180
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Default PVA glue...

Quote:
Originally Posted by JonasKarud View Post
I've done some experiments with Prostat DPF-401 and ordinary PVA glue,
and found that a mix of 25% glue and 75% Prostat produced a very tough
high resistance coating in the Gigaohm range.
Since PVA glues are not water proof, had you noticed any change in resistance with humidity?
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