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DanB
12-30-2008, 12:16 PM
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.:confused:

DanB
12-30-2008, 07:42 PM
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!

darinh
12-30-2008, 08:01 PM
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?

RandyL
12-30-2008, 08:01 PM
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,

Skybolt
12-31-2008, 07:12 AM
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.:confused:

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.

DanB
12-31-2008, 09:29 AM
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? :rolleyes:
Guess I have a few things to work on. Thanks again

RandyL
12-31-2008, 09:36 AM
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 (http://www.romeolima.com/RV3works/Paint/paint.html#Equipment).

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.

DanB
12-31-2008, 09:45 AM
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!

Skybolt
12-31-2008, 12:02 PM
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.

DanB
12-31-2008, 12:50 PM
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 (http://www.romeolima.com/RV3works/Paint/paint.html#Equipment).

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

Slyfox
12-31-2008, 03:24 PM
If I'm reading things right, you say that the fish eye happens in the same spot every time. That means there is contaminate on that surface. I to have had that problem, really pics a guy off when you do a beautiful job, come back an hour later and it still looks ok, but now you have a little pin hole, 2 hours later... BAM it looks like doggy doo. The best I can explain is to take some MEK and put it over the affected area, let it dry good and cross your fingers and paint again.

Slyfox
01-01-2009, 12:59 PM
I would like to add one little tid bit that just might help. If it's fish eye that starts with a little pin hole while painting, you can take your finger nail and swirl it in the center, than on your next pass with paint it generally sticks and fills in. Worth a try.

DanB
01-01-2009, 02:50 PM
In my quest to get things working correctly I mentioned above that I was going to exchange the original air/oil filter from Harbor Freight. I did this today and the second one does the same thing the first one did...It does not hold pressure to a constant when holding down on the sprayer trigger. I officially deem this filter a P.O.S. Don't waste your time. Looks like I will be ordering that M-30 Randy.
247

DanB
01-01-2009, 02:56 PM
I would like to add one little tid bit that just might help. If it's fish eye that starts with a little pin hole while painting, you can take your finger nail and swirl it in the center, than on your next pass with paint it generally sticks and fills in. Worth a try.


Steve,
I believe you are mistaking fisheye (a contaminant on the surface) with what happens when you miss a spot in the fabric weave when using Poly Brush. You will continue to get a pinhole when spraying until you manually fill in that hole.

Skybolt
01-01-2009, 07:56 PM
[QUOTE=DanB;1547]In my quest to get things working correctly I mentioned above that I was going to exchange the original air/oil filter from Harbor Freight. I did this today and the second one does the same thing the first one did...It does not hold pressure to a constant when holding down on the sprayer trigger. I officially deem this filter a P.O.S. Don't waste your time. Looks like I will be ordering that M-30 Randy.

Dan.
This could be getting off topic and going down another path...
A filter that removes oil aerosol does cost.
In the Auto Painting industry these water and oil filters can cost about $1,200 and could be around 2.5 thousand and up.

You say that this new filter and regulator does not hold pressure to a constant when pulling the trigger of the spray gun.

These canister filter / regulators are not supposed to maintain a constant pressure. It is the compressor and holding tank that does this. Most filter / regulators like the one shown should handle about 80 CFM at 120 psi (this does vary very much)

Lets say that your compressor delivers 10 CFM (cubic feet per minute) of air but the spray gun you are using consumes 14 CFM; the system will run down and you will see the pressure guage slowly move to the negative of what you started spraying with and before you know it, the atomisation of the paint gets poor and you will experience orage peel to say the least!

DanB
01-01-2009, 10:18 PM
[QUOTE=DanB;1547]In my quest to get things working correctly I mentioned above that I was going to exchange the original air/oil filter from Harbor Freight. I did this today and the second one does the same thing the first one did...It does not hold pressure to a constant when holding down on the sprayer trigger. I officially deem this filter a P.O.S. Don't waste your time. Looks like I will be ordering that M-30 Randy.

Dan.
This could be getting off topic and going down another path...
A filter that removes oil aerosol does cost.
In the Auto Painting industry these water and oil filters can cost about $1,200 and could be around 2.5 thousand and up.

You say that this new filter and regulator does not hold pressure to a constant when pulling the trigger of the spray gun.

These canister filter / regulators are not supposed to maintain a constant pressure. It is the compressor and holding tank that does this. Most filter / regulators like the one shown should handle about 80 CFM at 120 psi (this does vary very much)

Lets say that your compressor delivers 10 CFM (cubic feet per minute) of air but the spray gun you are using consumes 14 CFM; the system will run down and you will see the pressure guage slowly move to the negative of what you started spraying with and before you know it, the atomisation of the paint gets poor and you will experience orage peel to say the least!

Eric,
I understand what you are saying about the pressure is and should be held by the compressor. When I paint without putting the filter in line, I can maintain a constant pressure at the gun no problem. I can and have held the trigger for long stretches w/out my gun pressure dropping. When I put this goofy filter in line, strangely enough I will loose pressure at the gun all the way to zero. This I don't believe is normal operation.

Skybolt
01-02-2009, 05:21 AM
Dan.
You said>>>
"I believe you are mistaking fisheye (a contaminant on the surface) with what happens when you miss a spot in the fabric weave when using Poly Brush. You will continue to get a pinhole when spraying until you manually fill in that hole."

After you brush the Polybrush and let it dry. You then reduce the Polybrush and spray a couple of coats. If done right, this should have handled the migration of flex adhesive resins to the backside and through the weave of the fabric..

"When I put this goofy filter in line, strangely enough I will loose pressure at the gun all the way to zero. This I don't believe is normal operation."

This filter looks like a cheap replica of a USA, Binks model that was made for years. Probably made in China!
So it has the diaphragm (rubber disc)type regulator and the T screw adjuster at the top of the regulator. Turn the T to the right and you should watch the PSI go up on the gauge.
If you can adjust and set the working pressure for the spray gun to ,say 30 psi, and then when you pull the trigger the pressure is lost at the gun and the guage shows 0 psi then there is something not correct with the regulator.

With the T handle screwed to the left. Have you connected the main in line and no air line from the unit. Then slowly turned in the T, to see if there is any air coming out of the exit coupler?

Eric.

Lion8
03-19-2013, 06:17 PM
Painting issues. I used to restore old cars and custom painting same. I had the problem with oil in the line. On day while working my day job, I was tending a diver on a pile driving water rig when I asked the hard hat diver how he could breath that air with oil in it. He said he uses 'Synthetic oil' in his compressor. It doesn't vaporize. I changed it as soon as I got home.
Also, I don't paint in the rain or at night. If you do, you deal with high humidity (Blushing) and Bugs at night. This stuff should go into the tips and tricks section that John Pitkin started. -Tom, N.J.

Dave F
03-20-2013, 01:21 AM
Here is what I buy for our industrial set up. We run up to 2000 CFM from 3 compressors.

http://www.super-dry.com/images/Catalog.pdf

Also - fish eye is usually caused from the surface being painted. Some contamination is the culprit most of the time.