Fisheye in Paint Jobs

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lcorinth

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Sometimes I get this weird thing happening with my paint. I used to call it "moon pocks," because it looked like a pock mark or lunar crater, but I've since learned it's called fisheye.

It's where you spray paint and there's a spot - usually a round spot - where the paint does not cling to the rocket. The result looks something like this:

Fisheye1.jpg

Now, this picture, and the next one, are not mine. I found them via Google search. The reason I don't have my own is that each time this has happened, I've gotten really angry, and sprayed the rocket until I got the darned thing covered, then went back and sanded down the lumps and repainted.

Last week, I got a particularly bad case of fisheye, which looked a bit like this (again, not my photo):

Fisheye.jpg

Very frustrating.

Now, I sand carefully and try to get the rocket as clean as I can before painting. The thing I'm wondering is if this has to do with the method I'm using to clean dust off the rocket before painting.

Immediately after sanding, I rub the rocket down with a little rubbing alcohol on a clean cloth. Sometimes I don't paint right away, though, and dust may have settled on the rocket, or there may be lint left behind by the cloth I use to wipe it down with alcohol, so just before painting I gently wipe down the rocket with a tack cloth.

Now, I've heard a tack cloth can leave a residue on the surface, so I try to go very lightly with it, as I've read you're supposed to do. But I'm wondering if it's the tack cloth that's doing this.

I've only had this occur a few times, and only when using Krylon gloss enamel. I don't think it's occurred when I've used Rusto. Thing is, when the Krylon goes on well, I really like it. And I've had about the same success rate with Krylon and Rusto (due to an occasionally chunky can of Rusto).

But, in fact, my best paint job was with two colors of Krylon.

Astron Sprint XL Clone Smaller.jpg

My close second best was with Rusto.

DSCN2216.jpg

I only mention this because I know some folks aren't crazy about your basic gloss Krylon these days - apart from their one line of paint which is apparently more like the older formula (but which I haven't found around here).

My paint jobs are getting more consistently better, and I think this means my surface prep is generally pretty good, and my spray technique is getting better. But whenever I have something like this happen, it's so frustrating.

If it weren't for the fisheye problem, then I'd only have one Krylon paint job I wasn't happy with, due to a bad nozzle or a pigment clog or something.

I've read that fisheye is caused by oils, grease or wax on the substrate, which is what makes me suspect the tack cloth. Does this seem likely to anybody?

I'm wondering if some paints (i.e. the Krylon) are more sensitive to residues left on the rocket by the tack cloth than others (like Rusto). Should I be more careful with the tack cloth, or ditch it altogether? And if using a tack cloth turns out to be a less than ideal way to get dust off a rocket before painting, what would you guys suggest as a safe, clean way of doing it?

Thanks for your input, guys!
 

rharshberger

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Tack cloths are typically treated with boiled linseed oil to make them "tacky" which is a component of many paints, I don't think that BLO would cause fisheye. Silicone oil however will definitely cause issues with finishes (that's why many woodworkers and furniture repair people detest Pledge furniture polish). I lightly tack cloth all of my rockets after sanding and wiping down with either acetone or lacquer thinner, and the only fisheye effects I can attribute to anything so far were caused by insufficient mixing of the spray cans.
 

Screaminhelo

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I think that it is the tack cloth, I get the same results that you reported with them, I just use an old cotton t-shirt and alcohol.
 

Lowpuller

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If it is a plastic part, it may be mold Release. All of my plastic parts get a good washing with Dawn prior to any sanding or paint application.
 

Zeus-cat

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I think that it is the tack cloth, I get the same results that you reported with them, I just use an old cotton t-shirt and alcohol.
Use enough alcohol and you ain't gonna care what it looks like.
 

Micromeister

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Tack Rags absolutely not the problem, They are specifically created to remove dust & debris from sanded surfaces. Silicone, other mold release agents and such cause fish-eye.

Sometimes Alcohol leaves a bit of residue after drying, but I've never had it cause fish-eye if the subject surface is wiped down with a Tack rag or other dustless fabric just before painting.
 

Woody's Workshop

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Rubbing Alcohol I'd say.
Just before you paint, use a lintless paper tower (shop towel) for prepping.
Use a high quality mineral spirits (order less type, not the stinky paint thinner type).
Use a clean side of the tack cloth. They come in plastic bags. Save the bags.
Open it on 3 sides, and leave the dirty side out after use and fold the plastic bag over the tack rag for storage.
The 2nd photo of your "fisheye" problem is caused more by incompatible materials than contaminants.
There is special paint you can buy that is designed to go on and look like that. Though, I doubt one would want it on a rocket.
 

blackjack2564

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I NEVER use "rubbing alcohol". Most of them are only 70-90% alcohol, they can contain lanolin, water or other chemicals that keep from drying out skin when used.
READ the labels & check!
Any additives usually contain some oils which can and do effect paint work.

Be safe and buy some denatured Alcohol from Home Depot-Lowes-Ace- Best -Wal-Mart-or any hardware type store. This has no additives or water & will give great results.
 

CzTeacherMan

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I NEVER use "rubbing alcohol". Most of them are only 70-90% alcohol, they can contain lanolin, water or other chemicals that keep from drying out skin when used.
READ the labels & check!
Any additives usually contain some oils which can and do effect paint work.

Be safe and buy some denatured Alcohol from Home Depot-Lowes-Ace- Best -Wal-Mart-or any hardware type store. This has no additives or water & will give great results.
Ditto... However, I usually use acetone as my final dust wipe before painting.
 

K'Tesh

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After sanding the primer, I usually just wipe it with a damp rag, and allow it to dry.
 

mkadams001

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The rubbing alcohol may be the problem if it has other ingredients. However, Isopropyl alcohol should be only alcohol and water and should not be a problem with cleaning prior to painting. If you are not keeping the tack cloth clean then it may be the problem.

We use Isopropyl to clean prior to painting and application of various adhesives and VHB tape. (as recommended by 3M)

Part of the reason is that the Isopropyl does not leave oils behind like some thinners and solvents.

Even with a lot of cleaning, sometimes a fisheye pops up every now and then.
 

lcorinth

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Hmm. Well, I suppose it's possible I've used an unclean tack cloth in the past, though I think on this most recent job it was a new one (though I can't remember). I've stopped using the isopropyl alcohol just before painting, as I thought it might be chilling the surface too much and causing a problem. Now I do the alcohol right after sanding to remove the dust, and when I'm ready to paint - sometimes days or weeks later - I wipe the dust off with the tack cloth.

I always use Rustoleum Filler Primer, always wash plastic parts with dish soap after sanding (it's actually never happened on a nose cone before), and so far, I've only built paper rockets.

Also, if I remember correctly, this has only ever happened with Krylon gloss white - never a color, and never with the Rusto (though I've had other problems with Rusto).

I did shake the can well for over two minutes. But it may have been an old can. Perhaps that's it.

Dang. I was hoping the answer was "just quit using the tack cloth." Would have been pretty simple.
 

Lowpuller

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Wash the plastic parts before you sand. Otherwise you just grind the mold release into the material.
 

lcorinth

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Wash the plastic parts before you sand. Otherwise you just grind the mold release into the material.
Sorry, I actually misspoke. I do wash the parts before sanding, if I can feel mold release. On a recent build with a LOC nose, I definitely could feel the mold release, and washed it before doing any sanding. The whole nose cone felt kind of slimy before I washed it. Estes cones are fine, though. I just wash the dust off them when I'm done sanding the flash off.

But nose cones have never been a problem for me. They're the most consistently good-looking parts of my rockets, even if the body tube looks horrible.
 

BDB

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I've started wondering if the texture you noticed is caused by the Rusto filler primer. It is great for filling groves and covering blemishes, but I've had wrinkles when painting directly over it. Lately I've started using filler primer, sanding (repeat as necessary), then top coating with Rusto 2x primer, then paint. I'm far from an expert, but it seems to be working better.
 

Woody's Workshop

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High quality mineral spirits is designed for cleaning and prepping.
It has no interaction with any paints and evaporates totally, leaving no residue behind except excess dust and lint from your rag.
Doesn't matter if your using Lacquer, Enamels, Alkalies, or Water Based.
If it's over one type and under another type of paint.
Other products are for cleaning in harsher environments and on raw materials.
 

lcorinth

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I've started wondering if the texture you noticed is caused by the Rusto filler primer. It is great for filling groves and covering blemishes, but I've had wrinkles when painting directly over it. Lately I've started using filler primer, sanding (repeat as necessary), then top coating with Rusto 2x primer, then paint. I'm far from an expert, but it seems to be working better.
I don't think so. I use the Rusto Filler Primer for every rocket, and most of them turn out really great. Every now and then, I get a frustrating problem - either chunks from Rusto 2X paint or fish eye from Krylon.

Lately, the Rusto has been bad more frequently than I remember in the past. It may or may not be the cans I bought. I often order online now, since most hardware stores in Boston are small shops with very high prices, and I think the paint sits there a long time.

But I got some Rusto 2X semi-gloss white from Menard's, and about half the six cans I bought came out like Silly String. Worst texture I've ever had, and it came out of the can like that - made an awful sound and crapped chunks all over my rocket.
 

BDB

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I don't think so. I use the Rusto Filler Primer for every rocket, and most of them turn out really great. Every now and then, I get a frustrating problem - either chunks from Rusto 2X paint or fish eye from Krylon.

Lately, the Rusto has been bad more frequently than I remember in the past. It may or may not be the cans I bought. I often order online now, since most hardware stores in Boston are small shops with very high prices, and I think the paint sits there a long time.

But I got some Rusto 2X semi-gloss white from Menard's, and about half the six cans I bought came out like Silly String. Worst texture I've ever had, and it came out of the can like that - made an awful sound and crapped chunks all over my rocket.
That's a really good point that I hadn't considered: The amount of time that the paint has sat on the shelf a the store. usually buy from Home Depot or Lowes. I assume they have a faster turn than small hardware stores, but maybe I just got some old cans. There should be "Best if Used By..." labels on these things.
 

lcorinth

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That's a really good point that I hadn't considered: The amount of time that the paint has sat on the shelf a the store. usually buy from Home Depot or Lowes. I assume they have a faster turn than small hardware stores, but maybe I just got some old cans. There should be "Best if Used By..." labels on these things.
The six cans of Rusto 2X semigloss white I ordered from Menard's online. No idea how long they'd been sitting. Some of the local hardware store paint I bought was great, and some of it was terrible, but I've purchased both the Rusto and the Krylon.
 

les

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I ran into a problem with Rustoleum purple metal coat. I contacted them and they did indicate the paint has a max shelf life, which my can was beyond.
 

lcorinth

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I ran into a problem with Rustoleum purple metal coat. I contacted them and they did indicate the paint has a max shelf life, which my can was beyond.
Is there a date on cans? I'm not near my Rocket Room to check.
 

les

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No There is a lot number that they can cross reference, but not a date code that the user can read :(
 

TangoJuliet

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I use the Rusto Filler/Primer; sand with 320 grit typically, then wipe with just a dry cloth to get most of the sanded primer dust off, then spray with Testors rattle cans outdoors. 90% of the time I have zero issues - even in the high humidity of the Gulf South. Now mind you, I'm not going for glass smooth, zero drag, mirror finishes, but what I end up with is passable for what is on the face card from 3 feet away. :wink:
 

TangoJuliet

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ImageUploadedByRocketry Forum1499522724.339902.jpgImageUploadedByRocketry Forum1499522737.394689.jpgImageUploadedByRocketry Forum1499522751.256028.jpg
That's my enlarged, rear ejection Mosquito that the shock cord broke on last week on a C6-5. Testors rattle can Yellow and Black. Vinyl from Stickershock.
 
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