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Thread: Batteling Fish Eye

  1. #1
    Senior Member DanB's Avatar
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    Default Battling Fisheye

    I wish I could say that I was on a boat off a tropical coastline doing some blue water fishing, however, that's not it.
    I'm spraying my second wing at the Poly Spray stage. I got quite a bit of fisheye going on so I stopped and let the coat that I sprayed down dry for several hours. I went back and did some wet sanding with 400 grit over the affected areas...wiped it dry then hit the whole wing again with 2210 solvent. (I'm religious using this between coats).
    After the solvent dried I went to spraying again...same thing...I was getting fisheye in exactly the same spots that I sanded and cleaned.
    So...Who knows some tricks? I'm about ready to roll over and play dead.
    Last edited by DanB; 12-30-2008 at 02:56 PM.
    Dan B
    Mesa, AZ

  2. #2
    Senior Member DanB's Avatar
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    Default Re: Battling Fisheye

    I'm assuming by no replies others are as baffled as I. I know there are a multitude of possibilities as to why fisheye can occur...was just looking for a magic wand...I don't think there is one. I finally found the following off of a painting blog that gives the bitter truth. Thought I would paste it here for everyone:


    Fish Eyes in the Paint when Spraying
    Fish Eyes look like little craters on the moon where the paint pulls away from the center. (Looks well, like a fish eye and hence the name). Fish eyes occur immediately upon spraying. Fish eyes are caused by contamination of the surface you are spraying. Water, oil and silicone are the three major culprits. Also, if you leave the wax and grease remover on too long before wiping it off, it can cause fisheyes. When you wetsand out imperfections in the basecoat, sometimes there will be traces of water left causing the problem. To be honest, we had jobs where the fish eyes occurred and we had no idea what caused them as we could find no rhyme or reason for it.
    If we had a job that fish eyed, we would start over again by washing off the paint with automotive lacquer thinner. Once the surface fish eyes, the paint should be removed as something has contaminated the surface. You don't want to just sand down the surface and repaint as the problem will usually not go away. In all my years, we never found the paint or clearcoat itself to be the problem as often we would use the exact same paint and clearcoat again without difficulty. We started to think perhaps some truck was driving by spraying something with silicon in it as often we just could not come up with a reason for it!
    Dan B
    Mesa, AZ

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    Default Re: Battling Fisheye

    Dan,

    What is your painting setup? Oiled compressor or oil free? New hoses or old? Oil/water seperator inline? What about at your gun...do you have a disposable filter?

    Oil from your compressor can and often does cause fisheye as will any water that collects in your compressor tank. I found that during prolonged spraying, the hot air going into the tank would condense and create quite a bit of water. I have an inline fixed oil/water seperator and I also had a disposable filter at the gun that I changed after each painting phase or color. I also bought a new lenght of hose specifically for painting. I didn't have any problems with fisheye so something worked. By the way, I didn't clean between steps with 2210...I used a readily available wax and grease remover from the local autobody shop but it is probably the same stuff. One other question...you are using brand new virgin rags for the cleaning aren't you?

  4. #4
    Administrator RandyL's Avatar
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    Default Re: Battling Fisheye

    Dan, I feel your pain but can't really offer a real solution. My understanding is that silicon is the worst fisheye creator, though any sort of oil contamination is right behind it. I've now painted three metal airplanes and never once had any fisheye problems. I used all the normal prep techniques but certainly nothing extrordinary. What you found on the blog sounds like good advice in terms of starting over with the paint. Just a few things to check...
    -Could you have left your degreaser on too long?
    -Do you have adequate filtration on your compressor lines?
    -Could there have been any lubrication on the spray gun pivots that might have gotten into the product stream?

    Not having worked with the Poly Fiber products yet I don't know how easily they come off, but I think wherever you have fisheye you're going to need to take it back down to probably the silver. Couldn't hurt to call Poly Fiber when you have a minute and get their advice too.

    Hang in there,
    Randy Lervold
    TeamKitfox.com Admin Emeritus
    Day job: www.dynonavionics.com

  5. #5

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    Default Re: Battling Fisheye

    Quote Originally Posted by DanB View Post
    I wish I could say that I was on a boat off a tropical coastline doing some blue water fishing, however, that's not it.
    I'm spraying my second wing at the Poly Spray stage. I got quite a bit of fisheye going on so I stopped and let the coat that I sprayed down dry for several hours. I went back and did some wet sanding with 400 grit over the affected areas...wiped it dry then hit the whole wing again with 2210 solvent. (I'm religious using this between coats).
    After the solvent dried I went to spraying again...same thing...I was getting fisheye in exactly the same spots that I sanded and cleaned.
    So...Who knows some tricks? I'm about ready to roll over and play dead.
    Hi Dan.
    contaminant craters can come from lots of reasons. Either you put them on, the envirorment puts them on or the compressor puts them on.
    The reason they are there is because the is a big difference of surface tension between the substrate (you putting them on) or the contaminate that is entering the wet paint film during spraying (environment or compressor putting them on).

    Lets take a look at you; are you using bad towels to wipe the areas with the C-2210 cleaning solvent? Use only clean absorbant cloth. The towels have to be virgin, never used for anything else. Can you imagine if you used a towel for wiping the sweat from your face and then using before paint. Or wiping the grease from your hands!
    I look at this part of your message, maybe I am totaly wrong!!
    I went back and did some wet sanding with 400 grit over the affected areas...wiped it dry then hit the whole wing again with 2210 solvent. (I'm religious using this between coats).
    After the solvent dried I went to spraying again...same thing...

    You say that the solvent dried This could be the cause of the fish eyes. You should always remove the solvent before it has time to evaporate (dry) If you don't you can leave residue of the solvent components that do not agree with the top coat. And also you are not removing any contaminant that was on the surface to begin with, you are only moving it around and when the solvent evaporates, it is still there.

    If you are wet sanding the Polyspray, the sanding slurry / sludge can start drying before you thoroughly clean off. If there is residue from this, the solvent based C-2210 will not desolve the slurry. You will have to re-wet the slurry. A good cleaner for this would be to use a blend of 50 / 50 mix of Isopropyl Alcohol and bottled drinking water.
    Again, two clean towels. One for setting and abrading the surface and one for drying off before anything dries.

    Why are you using the C-2210 Surface Cleaner between coats?
    Use it correctly before you start spraying and anytime you stop and have to sand, But I don't think there is a benifit from using it between coats (after flash off)

    Eric.

  6. #6
    Senior Member DanB's Avatar
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    Default Re: Battling Fisheye

    Quote Originally Posted by darinh View Post
    Dan,

    What is your painting setup? Oiled compressor or oil free? New hoses or old? Oil/water seperator inline? What about at your gun...do you have a disposable filter?

    Oil from your compressor can and often does cause fisheye as will any water that collects in your compressor tank. I found that during prolonged spraying, the hot air going into the tank would condense and create quite a bit of water. I have an inline fixed oil/water seperator and I also had a disposable filter at the gun that I changed after each painting phase or color. I also bought a new lenght of hose specifically for painting. I didn't have any problems with fisheye so something worked. By the way, I didn't clean between steps with 2210...I used a readily available wax and grease remover from the local autobody shop but it is probably the same stuff. One other question...you are using brand new virgin rags for the cleaning aren't you?
    Darin,
    Thanks for the comments. I do have an oiled compressor with a filter at the gun. I have replaced this filter once. I bought an inline oil/water filter from Harbor Freight that didn't work (it blocked the air supply)...I may need to get a reputable filter system. Your idea of a new hose may now need to be implemented. The rags I am using come from a paint supply store (in a box). they look to be clean but they were t-shirts at one time... I take it that means they are not virgin? So where does one find virgin rags in this tainted world we live in?
    Guess I have a few things to work on. Thanks again
    Dan B
    Mesa, AZ

  7. #7
    Administrator RandyL's Avatar
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    Default Re: Battling Fisheye

    Might be onto something here. I too have a separate hose I use just for painting. More importantly I have a good filter I connect when painting, here is my setup.

    A belt-drive compressor (oil bath crank) will put a small amount of oil the the line. This is fine for normal air tool use but of course not for painting.

    When painting I connect one of those coiled 3/8" yellow hoses to the compressor and run it up the wall then back down to my filter (pictured in the link above) to cool the air. Then I connect my "painting hose" to the filter and paint away, no additional filter at the gun. This setup has painted three planes with no fisheye.
    Randy Lervold
    TeamKitfox.com Admin Emeritus
    Day job: www.dynonavionics.com

  8. #8
    Senior Member DanB's Avatar
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    Default Re: Battling Fisheye

    Quote Originally Posted by Eric Ashman View Post
    Hi Dan.
    contaminant craters can come from lots of reasons. Either you put them on, the envirorment puts them on or the compressor puts them on.
    The reason they are there is because the is a big difference of surface tension between the substrate (you putting them on) or the contaminate that is entering the wet paint film during spraying (environment or compressor putting them on).

    Lets take a look at you; are you using bad towels to wipe the areas with the C-2210 cleaning solvent? Use only clean absorbant cloth. The towels have to be virgin, never used for anything else. Can you imagine if you used a towel for wiping the sweat from your face and then using before paint. Or wiping the grease from your hands!
    I look at this part of your message, maybe I am totaly wrong!!
    I went back and did some wet sanding with 400 grit over the affected areas...wiped it dry then hit the whole wing again with 2210 solvent. (I'm religious using this between coats).
    After the solvent dried I went to spraying again...same thing...

    You say that the solvent dried This could be the cause of the fish eyes. You should always remove the solvent before it has time to evaporate (dry) If you don't you can leave residue of the solvent components that do not agree with the top coat. And also you are not removing any contaminant that was on the surface to begin with, you are only moving it around and when the solvent evaporates, it is still there.

    If you are wet sanding the Polyspray, the sanding slurry / sludge can start drying before you thoroughly clean off. If there is residue from this, the solvent based C-2210 will not desolve the slurry. You will have to re-wet the slurry. A good cleaner for this would be to use a blend of 50 / 50 mix of Isopropyl Alcohol and bottled drinking water.
    Again, two clean towels. One for setting and abrading the surface and one for drying off before anything dries.

    Why are you using the C-2210 Surface Cleaner between coats?
    Use it correctly before you start spraying and anytime you stop and have to sand, But I don't think there is a benifit from using it between coats (after flash off)

    Eric.
    Eric, Interesting point about the sanding slurry possibly drying. I will be more attentive to that as well as the rags I am using...you would think they would be ok comming from a paint shop, but they did used to be t-shirts.
    The Poly Fiber manual recommends cleaning with the 2210 between crosscoats...That would be after one crosscoat dries several hours and then cleaning again just prior to spraying.
    Thanks again for the ideas!
    Dan B
    Mesa, AZ

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    Default Re: Battling Fisheye

    Ther only reason I can see Polyfiber explaining to use the C-2210 solvent / surface cleaner between coats is that the Polyspray (silver) should be allowed to dry before continuing with more coats, who knows how long some people will take between coats.
    Now' if the environment is dusty and dirty and there is possibility for contaminate to settle on the dried coat...then a double rag cleaning is a good suggestion.
    As to the rag, being recycled T-shirt material.. this should be good if they have gone through a good laundry cycle.

    If oil aerosols are coming from the compressor. This will be difficult to remove without the use of correct in line filters, made for this reason.

    If you start to see these fish eyes next time you start to paint... allow a good flash off and start to mist coat the area. Do not want to get the paint too wet or you will get larger craters. A couple of light mist coats should keep the fish count down!

    Eric.

  10. #10
    Senior Member DanB's Avatar
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    Default Re: Batteling Fish Eye

    Quote Originally Posted by RandyL View Post
    Might be onto something here. I too have a separate hose I use just for painting. More importantly I have a good filter I connect when painting, here is my setup.

    A belt-drive compressor (oil bath crank) will put a small amount of oil the the line. This is fine for normal air tool use but of course not for painting.

    When painting I connect one of those coiled 3/8" yellow hoses to the compressor and run it up the wall then back down to my filter (pictured in the link above) to cool the air. Then I connect my "painting hose" to the filter and paint away, no additional filter at the gun. This setup has painted three planes with no fisheye.
    Randy, It looks like we have the same compressor. I looked up your filter and it looks reasonable in price. I'm going to take back the Harbor Freight and exchange it to see if #2 will allow the air through...If not, I will order the M-30. I Plan to get a new hose as well. Hopefully this will take care of the problems.

    Eric, Thanks as well for the tips. As I was reading how to correct issues w/ fisheye I did read how sometimes lightly spraying only solvent across the area allowing the contaminent to "bleed out" might work.
    cheers
    Last edited by DanB; 12-31-2008 at 12:54 PM.
    Dan B
    Mesa, AZ

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