Hello All,
First, thank you for any advice you can provide. I realize this is a probably a rookie question but here goes.
I am in the process of building my first pair of ESL's using 12"x48" perforated metal stators. I have trimmed them to size and ground down all the sharp edges to avoid arcing. The next step I'm planning is spraying them with Rust-Oleum Automotive Acrylic Lacquer. First a good coat of Gloss Black followed by many coat of the Clear to build up approximately 10mil of insulation.
My question is if I should be using a primer as a first step before the gloss black?
I have read about a number of folks who have used primer but not sure if it is essential or not to get good adhesion for the paint. Also, have read about etching primers. Are these necessary?
Any thoughts are very welcome.
Many thanks.
-Noonan
First, thank you for any advice you can provide. I realize this is a probably a rookie question but here goes.
I am in the process of building my first pair of ESL's using 12"x48" perforated metal stators. I have trimmed them to size and ground down all the sharp edges to avoid arcing. The next step I'm planning is spraying them with Rust-Oleum Automotive Acrylic Lacquer. First a good coat of Gloss Black followed by many coat of the Clear to build up approximately 10mil of insulation.
My question is if I should be using a primer as a first step before the gloss black?
I have read about a number of folks who have used primer but not sure if it is essential or not to get good adhesion for the paint. Also, have read about etching primers. Are these necessary?
Any thoughts are very welcome.
Many thanks.
-Noonan
Everything sounds good so far, and, YES you should primer them !!
I would start with a coat of etching type primer as this stuff is very tough and it creates a good solid bond to the metal.
Then add your regular primer.
DO USE the RED primer and not any gray's or black primers as they contain Titanium Dioxide (gray) and carbon black and these will conduct at high voltages!!
Especially Titanium Dioxide I have not tested the black one yet at this time.
The red primers use Talc as a filler and Talc is a great insulating substance.
Use a heavy build type as it has a higher content (nearly double) of the amount Talc.
Talc also has a high Dielectric constant of around 9.41 and this to is good.
http://www.minsocam.org/ammin/AM21/AM21_115.pdf
In my tests I have found that just the red primer type has as good as if not slightly higher dielectric strength than the clear does.
I gotten about 1500v to 1900v per mil in my test using such paints, and just the primer alone was consistently on the higher side of this scale as I had posted in this thread,
http://www.diyaudio.com/forums/plan...tric-coatings-fact-fiction-2.html#post2894427
http://www.diyaudio.com/forums/plan...tric-coatings-fact-fiction-2.html#post2893839
The whole thread is great and should be read through in its entirety.
After a good coat or two (or 3&4) of primer (red) then use one coat for color and then build the rest up with clear as you had planned.
The primer coatings will be about 4 mil or so.
Make sure that you spray it from all four quadrants of the panel in order to get complete coverage in the inside wall of the holes as well.
It has been almost about 2 years since I made the sample in the photos and I still have it.
It is very flexible to work with and has yet to form any micro cracks after this long of time.
The last time I had tested it was about 6 months ago and I will test it again sometime soon but so far it has not failed my 13.5Kv tests and the coating is only about 8 mils thick (.008").
jer
I would start with a coat of etching type primer as this stuff is very tough and it creates a good solid bond to the metal.
Then add your regular primer.
DO USE the RED primer and not any gray's or black primers as they contain Titanium Dioxide (gray) and carbon black and these will conduct at high voltages!!
Especially Titanium Dioxide I have not tested the black one yet at this time.
The red primers use Talc as a filler and Talc is a great insulating substance.
Use a heavy build type as it has a higher content (nearly double) of the amount Talc.
Talc also has a high Dielectric constant of around 9.41 and this to is good.
http://www.minsocam.org/ammin/AM21/AM21_115.pdf
In my tests I have found that just the red primer type has as good as if not slightly higher dielectric strength than the clear does.
I gotten about 1500v to 1900v per mil in my test using such paints, and just the primer alone was consistently on the higher side of this scale as I had posted in this thread,
http://www.diyaudio.com/forums/plan...tric-coatings-fact-fiction-2.html#post2894427
http://www.diyaudio.com/forums/plan...tric-coatings-fact-fiction-2.html#post2893839
The whole thread is great and should be read through in its entirety.
After a good coat or two (or 3&4) of primer (red) then use one coat for color and then build the rest up with clear as you had planned.
The primer coatings will be about 4 mil or so.
Make sure that you spray it from all four quadrants of the panel in order to get complete coverage in the inside wall of the holes as well.
It has been almost about 2 years since I made the sample in the photos and I still have it.
It is very flexible to work with and has yet to form any micro cracks after this long of time.
The last time I had tested it was about 6 months ago and I will test it again sometime soon but so far it has not failed my 13.5Kv tests and the coating is only about 8 mils thick (.008").
jer
This is extremely useful Jer, thanks!
Looks like I'm headed back to the auto parts store for etching primer and regular primer (red). On Rust-Oleum's website I see only one Self-Etching Primer as per link below. It is dark green in color and has Carbon Black as an ingredient. Is this an appropriate product to use? Or is there one you know of that is red or clear?
http://www.rustoleum.com/MSDS/ENGLISH/249322.PDF
One other question: I was planning on hanging my stators by an edge while spraying. I was thinking of using a very thin gauge wire and placing them through the perforations that will eventually be under the spacers. Obviously, there will be areas that will not get coated as well or at all. I'm guessing that won't work and I will have to move the wires around so that everything gets an even coat of insulation. Thoughts?
Many thanks.
-N
Looks like I'm headed back to the auto parts store for etching primer and regular primer (red). On Rust-Oleum's website I see only one Self-Etching Primer as per link below. It is dark green in color and has Carbon Black as an ingredient. Is this an appropriate product to use? Or is there one you know of that is red or clear?
http://www.rustoleum.com/MSDS/ENGLISH/249322.PDF
One other question: I was planning on hanging my stators by an edge while spraying. I was thinking of using a very thin gauge wire and placing them through the perforations that will eventually be under the spacers. Obviously, there will be areas that will not get coated as well or at all. I'm guessing that won't work and I will have to move the wires around so that everything gets an even coat of insulation. Thoughts?
Many thanks.
-N
The etching primer you describe is the stuff as it has Titanium dioxide as the pigment and it comes out as a grayish green color.
It is okay as it is the very first coat.
I don't know of any other colors for this type of primer.
Hanging the panels is okay but you may have a better result laying them flat on some sort of standoffs.
This will help you to get around the panel easier to make sure the holes are properly coated on the insides of them.
And it will help you to avoid any runs in the coating.
You will also have a more consistent thickness of the coating across the whole area of the panel as well.
However works best for you as long is you don't create any runs.
You want the paint to go on wet so that it flows out but you don't want it to flow too much (you know what I mean).
Also how ever you choose to mount it for painting don't lean it up or let it touch anything before the paint is fully cured!!!
I was in a hurry one day and I didn't set my panels up properly to cure and in a mater of just a few minute they had stuck to the box I had them in and it peeled the paint right off trying to get them unstuck from the box!!
Luckily it was not in a critical area and I was able to redo that one section.
Another DIYer had done the same thing not too long ago and he wasn't as lucky and had to start all over again!!!
Here is the start of my painting process,
A Segmented Stator Desktop ESL
and here is were it got stuck to the box and peeled it right off,
A Segmented Stator Desktop ESL
As you go through the rest of the thread I show each step as the coating gets built up more and more as well as fixing the bad spot.
For the clear coat it is cost effect to use the Thicker 2X or 3X stuff if you are using spray bombs.
At one point I had found some regular clear off brand paint at the now Defunct Pamida stores for $1.87 a can and it is the very same paint as the Rustoelum brands as it tested the same voltage wise and it is just clear acyrlic enamel.
That was the very same paint that I had used on my sample window screen stator.
Menards and in my area has the best price on a can of the 2X for under $4.
I got lucky one day when Mejiers had %25 more cans for the same price as the regular ones!!
I think I listed all of the UPS codes in the coatings thread in this post,
http://www.diyaudio.com/forums/plan...tric-coatings-fact-fiction-2.html#post2894629
I was using some Sherwin Williams etching primer at the time but on my new build I used Rustoleums Clean Metal Primer #7780.
According to the MSDS I believe it is an acid based primer therefore an etching type.
jer
It is okay as it is the very first coat.
I don't know of any other colors for this type of primer.
Hanging the panels is okay but you may have a better result laying them flat on some sort of standoffs.
This will help you to get around the panel easier to make sure the holes are properly coated on the insides of them.
And it will help you to avoid any runs in the coating.
You will also have a more consistent thickness of the coating across the whole area of the panel as well.
However works best for you as long is you don't create any runs.
You want the paint to go on wet so that it flows out but you don't want it to flow too much (you know what I mean).
Also how ever you choose to mount it for painting don't lean it up or let it touch anything before the paint is fully cured!!!
I was in a hurry one day and I didn't set my panels up properly to cure and in a mater of just a few minute they had stuck to the box I had them in and it peeled the paint right off trying to get them unstuck from the box!!
Luckily it was not in a critical area and I was able to redo that one section.
Another DIYer had done the same thing not too long ago and he wasn't as lucky and had to start all over again!!!
Here is the start of my painting process,
A Segmented Stator Desktop ESL
and here is were it got stuck to the box and peeled it right off,
A Segmented Stator Desktop ESL
As you go through the rest of the thread I show each step as the coating gets built up more and more as well as fixing the bad spot.
For the clear coat it is cost effect to use the Thicker 2X or 3X stuff if you are using spray bombs.
At one point I had found some regular clear off brand paint at the now Defunct Pamida stores for $1.87 a can and it is the very same paint as the Rustoelum brands as it tested the same voltage wise and it is just clear acyrlic enamel.
That was the very same paint that I had used on my sample window screen stator.
Menards and in my area has the best price on a can of the 2X for under $4.
I got lucky one day when Mejiers had %25 more cans for the same price as the regular ones!!
I think I listed all of the UPS codes in the coatings thread in this post,
http://www.diyaudio.com/forums/plan...tric-coatings-fact-fiction-2.html#post2894629
I was using some Sherwin Williams etching primer at the time but on my new build I used Rustoleums Clean Metal Primer #7780.
According to the MSDS I believe it is an acid based primer therefore an etching type.
jer
Attachments
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Here is a copy of a two part PM that I sent to a Fellow DIYer "Waldruat" on my views of the painting process.
I get asked these things a lot so maybe this will help as well.
Once you read through all of this and you apply your last coat do not wipe it down with denatured alcohol as I had done in between coats. This will dull the glossy finish of the final coat as you will see early on during the whole process on the succeding coats.
A flat paint may work as well for your color coat.
Flat paints typically contain "Silica" a very fine form of silicon Dioxide or Glass if you will.
I have not yet taken the time to test such paints but it was mentioned one day in a discussion I had with Roger Sanders about stator coatings and was something he was experimenting with back in 2003.
So, I had subscribed to Paint and Powder magazine and shortly after there were many write ups in it about using Glass Micro spheres in paints and such.
He had explained to me how they would benefit in making a higher dielectric strength coating than just paint or powder itself.
Much the same way that talc does.
I noticed the other day while I was at Habor Freight that they carried raw Silica in the paint and powder coating section and it is quite a very fine grade of type material.
I will be getting some of this stuff for future coating experiments, as I am always searching for that "Holy Grail" in stator coatings!!!!!.
jer
I get asked these things a lot so maybe this will help as well.
Once you read through all of this and you apply your last coat do not wipe it down with denatured alcohol as I had done in between coats. This will dull the glossy finish of the final coat as you will see early on during the whole process on the succeding coats.
A flat paint may work as well for your color coat.
Flat paints typically contain "Silica" a very fine form of silicon Dioxide or Glass if you will.
I have not yet taken the time to test such paints but it was mentioned one day in a discussion I had with Roger Sanders about stator coatings and was something he was experimenting with back in 2003.
So, I had subscribed to Paint and Powder magazine and shortly after there were many write ups in it about using Glass Micro spheres in paints and such.
He had explained to me how they would benefit in making a higher dielectric strength coating than just paint or powder itself.
Much the same way that talc does.
I noticed the other day while I was at Habor Freight that they carried raw Silica in the paint and powder coating section and it is quite a very fine grade of type material.
I will be getting some of this stuff for future coating experiments, as I am always searching for that "Holy Grail" in stator coatings!!!!!.
jer
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I just posted in the "ML membrane rebuild" thread, but saw a similar discussion here about stator coating so I will add my $0.02 here also. I followed Jer's painting procedures and used 3 coats of Rustoleum Red Filler/Primer (not easy to find for some reason...ended up buying on-line) followed with a gloss back, and maybe three coats of clear (one of the coats was with a 2X "painters" coat.) I have had problems with DS tape lifting from the stators and thus failing to hold the Mylar tension (mostly my fault because I was following Jazzman's original tape procedure...the new procedure calls for wrapping the tape over the stator edges. Very important!) In my first attempt to build Jazzman's ESLs, I applied only one coat of Rustoleum gloss black to the stators (not enough paint to prevent arcing, hence I am rebuilding them.) I noticed, however, the DS tape stuck much better to one coat of gloss black compared to the clear coat I am using now. Wondering how that could be possible? Too late to do anything about that now. I will be clamping the ESL panels (rebuilt with the new taping procedure) to new maple frames I have built to insure the completed stators don't come apart. HTH.
Thank You for your input on this!!!
I am unfamiliar with using the DS tape methods and this is very good info to know.
Although, I am curious to know if you have experienced any damaging or lifting of the stator coating or did it just slide from the position that it was original applied.
I want to build some new small panels using widnow screen and I have not yet tried any types of glues on my sample to see if any of them might cause failures in the integrity of the painted coating, namely Super Glues.
One suggestion that I had given WreckingBall was to glue down a strip of some thin plastic (.010" to .020" thick or so) around the perimeter of the stator.
He suggested to use epoxy as Super glue may damage the coating, This is something that I will have to investigate.
The plastic strip will give a solid foundation for the DS tape to bond to from what is lacking due to the holes.
If the new Taping method works than all is good, But only time will tell.
Make sure that you clean the perimeters of the stator's and the mylar with some Denatured Alcohol as well as the slightest bit of finger oils will also cause the sticky on the tape to fail and slide off as well.
jer
I am unfamiliar with using the DS tape methods and this is very good info to know.
Although, I am curious to know if you have experienced any damaging or lifting of the stator coating or did it just slide from the position that it was original applied.
I want to build some new small panels using widnow screen and I have not yet tried any types of glues on my sample to see if any of them might cause failures in the integrity of the painted coating, namely Super Glues.
One suggestion that I had given WreckingBall was to glue down a strip of some thin plastic (.010" to .020" thick or so) around the perimeter of the stator.
He suggested to use epoxy as Super glue may damage the coating, This is something that I will have to investigate.
The plastic strip will give a solid foundation for the DS tape to bond to from what is lacking due to the holes.
If the new Taping method works than all is good, But only time will tell.
Make sure that you clean the perimeters of the stator's and the mylar with some Denatured Alcohol as well as the slightest bit of finger oils will also cause the sticky on the tape to fail and slide off as well.
jer
The first two rebuild times the Mylar wrinkled while I let the Licron dry. The tape pulled up from the stator in several places. After getting very annoyed and sitting down with a Troegs Double Bock I figured I had to come up with a way to apply both the front and rear stators at the same time to keep the Mylar fully stretched, and the tape down firmly. I cut a hole in the stretching board I made so that I could apply the rear stator to the Mylar from the bottom, apply the Licron, then apply the front stator on top. Not easy to do it this way, but I thought I had the problem licked. Nope. This time, on the third rebuild, the tape moved on both sides of the assembled panel enough to release most of the tension. Keep in mind this was before I discovered Jazzman's revised tape process (wrapping over the edges) and I didn't clamp the panels in the frames I was using at the time. The tape moved on both panels within a day or two of assembling them. I was careful to wipe the Mylar down with alcohol, and never touched the panels with bare fingers while assembling them (cotton gauze gloves from CVS are useful...
Using the tape-over-the-edge process, I will get it right this time (number 4....)
Using the tape-over-the-edge process, I will get it right this time (number 4....)
I have always had problems with tapes. They creep. The fact that adhesive does not harden makes it very problematic on holding long term loads.
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Hi,
I never had probs, neiter shorttime nor logtime, with the 3M tapes.
It will be essential though to use the right tape according to the bonding partner, i.e the stator's top coating material.
I'm no friend of acrylic enamels so far, simply because I always had issues to get an nice even surface as they dried out too quick. I prefer solvent based PU laquer, used for staircases or boats.
The PU is very tough, yet it gives very smooth and glossy surfaces.
I hung my panels from the ceiling with strings and coated with a spray gun 8 times (4x each side).
Changed the direction of the spraygun nozzle 45° with every run to get a nice thick layer of coating at the whole edges.
This laquer and the VHB tapes form an nearly unbreakable joint.
Other manufactures of tapes had issues though. Thick tapes will proabely be troublesome too.
If high mechanical tension is required as in the vertical direction of curved panels, the wrap-around-the-edge technique using thin tape is mandatory.
jauu
Calvin
I never had probs, neiter shorttime nor logtime, with the 3M tapes.
It will be essential though to use the right tape according to the bonding partner, i.e the stator's top coating material.
I'm no friend of acrylic enamels so far, simply because I always had issues to get an nice even surface as they dried out too quick. I prefer solvent based PU laquer, used for staircases or boats.
The PU is very tough, yet it gives very smooth and glossy surfaces.
I hung my panels from the ceiling with strings and coated with a spray gun 8 times (4x each side).
Changed the direction of the spraygun nozzle 45° with every run to get a nice thick layer of coating at the whole edges.
This laquer and the VHB tapes form an nearly unbreakable joint.
Other manufactures of tapes had issues though. Thick tapes will proabely be troublesome too.
If high mechanical tension is required as in the vertical direction of curved panels, the wrap-around-the-edge technique using thin tape is mandatory.
jauu
Calvin
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