Whether you have fish eyes moon craters, hairs, lint, specks, or bumps, take your time. The only method of prevention is to keep all silicone products out of the paint area. Fitzs atlas 2 of coating defects fitzs atlas of coating defects and. The fact that you see this on galvanized or galvanneal would not likely be because of the metal itself. When a coating is applied to a substrate that is contaminated with low surface energy particles such as oil, wax, grease, or silicone, fish eyes may develop in the coating as it is applied. Coating defects coating streaks are continuous defects that may be very clear and long, but they can be short and extremely narrow.
A book you can count on paperback august 17, 1992 by lois ehlert author visit amazons lois ehlert page. Fish eyes are round separations or indentions in the coating finish. The remedy is to thoroughly clean the surface and if spray painting, to ensure that there is an oil filter on the air line. Fish eyes paint defect anodizing, plating, powder coating. It is also possible, that mistakes were made during the coating process maybe the coat thickness was not right or drying times were too short. Fish eye or bird eye a paper defect appearing as glazed, translucent spot caused by slime, fiber bundles, andor improperly prepared chemical additives in the stock. Adhesive coating defects causes remedies slideshare. All substrates have a surface energy and as a general rule, adhesion is achieved when the surface energy of the substrate is 810 dynescm greater than the surface. Top 10 auto paint repair problems and solutions fish eyes tiny surface finish blemishes that resemble small circles of popped paint bubbles, of fish eye appearance. Defects and problems do occur while automotive coatings are being applied or soon after, especially during one or another of the bakes. If the surface has been properly cleaned and degreased using a wax and grease remover, fish eye can usually be prevented completely. This defect is indicated by small round imperfections in the top coat.
These defects hurt appearance and may compromise the protective ability of the coating. As release agents are designed to prevent adhesion between surfaces, they can interfere with paint adhesion or plating, resulting in a fish eye defect, if they are. As it is my first time dealing with powder coating, i am learning about it on the job. I am senthil working as a quality executive in akzo nobel coatings india in powder bu. Achieving a good balance between the two will aid in avoiding defects, such as crawling, craters, and fish eyes. Jul 31, 2014 fish eyes are a type of coating defect which is characterized by circular voids or separation in the coating. Characterized by circular voids or separation in the coating can be caused by oily spots or silicone particles andor by airborne droplets that are deposited on the painted surface.
Accumulation of dirt, dust particles, fiber and hair, on the adhesive film. In order to improve the lines, i need to understand what causes the defects in the coatings. When they occur they must be sanded and repaired, which can lead to additional defects. Layering is where multiple layers of conformal coating are applied to a circuit board and do not adhere to each other or cause incorrect curing of the individual layers. Chart on fish diseases, symptoms and their treatments. Some things probably more then others but in my opinion if you have a can of wd40 sitting on a shelf it wont cause problems. Increasing and maintaining optimum surface energy will help you eliminate common defects such as craters, fish eyes, or film separation in your conformal coating process. Feb 01, 2009 the molten powder coating crawls around the contamination during the cure cycle and forms a round defect that usually includes a small spot or dome in the center. Fish eyes are a typical defect when paint is sprayed. Jan 28, 2019 paint fisheyes show themselves as a small round or circular shaped defect that can have a crater in the center. Fish eyes, nasty little peasized craters in a finish film, occur when the wet finishs surface tension keeps it from flowing over slippery contaminants on the work. May 16, 2020 those coating defects or failures are primarily instigated by coating applicators poor surface preparation and wrong application techniques etc. Excessive temperatures in the coating system correct condition provide circulation cool, reconstruct 2. A total of 118 different defects are featured with.
A discussion started in 2005 but continuing through 2019. Fish eyes are a type of coating defects which looks like circular voids or separation in the coating. Deposits agglomerates form in the powder feed hoses, which sporadically are freed by delivery air and appear as powder puffs on the work pieces. As release agents are designed to prevent adhesion between surfaces, they can interfere with paint adhesion or plating, resulting in a fish eye defect, if they. Jan 01, 2018 fisheyes are defects in the paint film that appear as small depressions with a mound in the center that resembles a fish eye, thus the term. If the central underlying substrate area is visible, the defect is known as cissing. Rejects are the bane of any job shops existence when applying powder coatings. The ability of a coating to wet a surface is vital to achieving a uniform and defect free coated layer and depends both on the surface tension of the coating, and the surface free energy of the substrate. Pulling a part out of the oven only to see disappointing orange peel spoiling the powder coated finish, sections where the coating has sagged, or opacity issues, bring a sigh of frustration, alongside the question of what happened. Flashlights or spotlights are required for inspections inside tanks, vessels, pipes, etc. Cratering phenomenon from base material fish eyes phenomenon in paint film layer cratering fish eyes causeresult analysis chart cratering application work paint putty drying others. Generally speaking, that contaminant is a light oil silicon, which. Of this story i can say that it came to me in an irresistible form, crying to be written. I have a previous blog post where i explain this as well.
Remove wet paint film with solvent, clean and refinish. Fish eyes look like penny size or smaller craters in the surface of your powder coated part. If you have more than one piece to paint, try using the water break free test first to insure you have an adequately clean part in which to apply the powder to. Jul 30, 2019 fish eyes are a type of coating defects which looks like circular voids or separation in the coating. Simple steps to resolve conformal coating wetting problems. Roll and web defect terminology tappi press roll and web defect terminology by r. However, a low power pocket microscope can enhance the details of suspected defects. Understanding liquid film defects products finishing. Do not use fisheye eliminator in undercoats or basecoat color. Pulling apart out of the oven only to see whorls of orange peel powder, sections where the coating has sagged, or opacity issues bring a particular kind of dread alongside the question of what happened. Oil, fat, wax and silicone polish residue were not thoroughly removed from the surface to be coated. The first thing id suspect is the airline oil eventually starts leaking in the compressor and it will cause fish eyes, unless you have a good, well maintained oiltrap. Looking at the vibartion spectra shows a similar impact, but now we can start to discriminate at which frequency the hard coating assumed to be stripped away after blade change cause vibration.
The best approach to eliminate these common coating defects is to ensure that you have the proper surface energy throughout every step prior to conformal coating and take. When coating is applied on top of the contaminant, the conformal coating is unable to adhere to the oily surface and. Avoid overheating the surface during the bake time. Defects in coatings characterized by small circular craters that look like a fish s eye. If so, the contamination is in the spray system, finish, or solvent. Coating defects fault finding coating defects car straight out of the oven into a cooler room. On the other hand, coating splashes may provide a clear contrast with a specific shape. As with many of the paint defect, applying too much material too fast is the leading cause for this problem.
Like little volcanoes on the surface of the powder coating. Aug 07, 20 fisheyes are not defects and generally become undetectable once the film is applied to label stock. Moisture absorption forms the substrate especially from putties and fillers before painting. Deposits of residual silicone on the surface of the floor cause this type of imperfection. Troubleshooting finish fisheyes caused by contamination. Fish eyes are imperfections in the surface of the epoxy coating, which resemble the fish eyes.
Ive been having trouble with many of my coatings, i keep getting fish eyes and i cant figure out why. Im going to try spraying some of your hydrocote resisthane for the first time. This is a concept book on so many levels, and an activity book as well. Fish eyes cissing craters are circular dents with raised edges in the topcoat or the intermediate coats. Fish struggles to swim, may float with head tipped down, or have difficulty surfacing, no balance, etc. What causes solvent pop and fisheye in automotive paint. Conversely a coating that beads up, forms defects such as fish eyes, or forms a film with gaps or variations in thickness has bad wetting or does. Coating failures coatings degradation coating flaws. Examples of conformal coating fish eyes examples are shown in the images. Fish eyes can be caused by oily spots or silicone particles andor by airborne droplets that are deposited on the coated surface. What is pcb surface energy and how does it affect conformal. Skip can be very subtle and detection is the main problem. Pop eye exophthalmia otc medication for bacterial infections andor parasites. Cissing and dimpling sometimes known as crawling or fisheyes are very small circular defects, where the paint has receded to expose the underlying substrate or coating.
As release agents are designed to prevent adhesion between surfaces, they can interfere with paint adhesion or plating, resulting in a fish eye defect, if they are not properly removed by the cleaning process. During the first 2472 hours this adhesive flow eliminates the appearance of the fisheyes. Add the recommended fisheye eliminator and respray the affected area. To avoid this type of imperfection, make sure that you properly prepare the concrete surface with the recommended solvent or stripping agent to remove any. Silicone oil is by far the most effective and most common culprit in fish eye formation when finishing wood. These fish eyes are produced because the coating is unable to wet out the contaminated area. Today for the first time, we received a complaint of cratering defects by one of our customer. A discussion started in 2007 but continuing through 2018. Fish eyes are small, craterlike openings in the finish after it has been applied. Typically, that contaminant is a substance like a silicon contaminant.
As you can imagine, outgassing makes a mess of a coating. We are experiencing fish eyes, undercoating and coating buildup. Maybe your customer had an accident, or maybe the car was exposed to aggressive atmospheric conditions. The main reason behind why this problem happens is something is happening with the surface of the substrate before coating most commonly porosity below the surface of the substrate or oxidation on the surface. There are some other names such as poor wetting, crater formation and cissing. Troubleshooting coatings advanced polymer coatings. Please could someone be so kind as to tell me the causes of the defects in our products.
A fish eye is a localised dewetting defect that looks like a fish eye crater on the surface of the conformal coating. Fisheyes are almost always caused by residual oil, grease or silicone products. To eliminate this problem, follow recommended film thickness and wait recommended flash time. Reduction of the surface tension is required to avoid fish eyes. They are usually caused by oil and grease on a coating substrate. Fish eyes are normally caused by a contaminant on the surface prior to application of the conformal coating. This results in the exposure of the substrate metal to corrosion causing agents and eventual degradation. Surface contamination or condensation, incompatibility between coating systems.
Complete details of coating faults and paint defect the. Free shipping get free shipping free 58 day shipping within. Apr 09, 2018 cracking refers to a type of coating defect that is characterized by the chipping away of the applied paint film in small sections or entirely. It could also be due to the bake system, if it was set too hot. Fisheyes are small circular, craterlike openings that appear during or shortly after application potentially caused by painting over surfaces contaminated with oil. Now hes discovered he can poke his finger into the fish eye holes, and i can touch it from the back of the page, or move my finger over the back of the holes so the fish seem to blink.
The defect is caused by traces of silicone or oil on the surface prior to painting. You must keep notes during any type of troubleshooting. Download our pdf guide solving conformal coating problems in the application process now. Fisheyes tend to show themselves as you apply a coating on the surface or immediately after the surface has been coated. As release agents are designed to prevent adhesion between surfaces, they can interfere with paint adhesion or plating, resulting in a fisheye defect, if they. If fish eye does occur, particularly in the first coat, often painters will let that. When there are problems in the paint finish, all direction is often lost on how to troubleshoot. Fish eyes are a type of coating defect which is characterized by circular voids or separation in the coating.
A fisheye is caused by a contaminant on the surface of your paint project. Fish eyes in powder coating are most often the result of contamination in your products surface. Jan, 2020 in fish eye, the paint separates and is not sticking. Jul 31, 2018 powder coating application problem 3 fish eyes. Dont bother looking any where else because its a waste of time. Paint defects 1 1 cratering 2 dust nibs 3 orange peel 4 sagging 5 poor opacity cratering fish eyes cratering and fish eyes occurs partly on the paint surface, and the film becomes uneven.
They are called fisheyes because they look like it. I manufacturefinish parts and frequently encounter fish eyes on products. All coating and application defects have high quality photographic examples allowing the reader to assess the probable type of defect. I have tried many ideas to narrow down the contaminant but always fail. Automotive paint defects lesson 12 how to identify and. If fisheyes appear in a basecoat, allow the color to flash then spray a mist coat over affected area. After some time chasing the problem mysteriously disappears. During lamination, the air is eliminated from between the layers of selfwound and the adhesive flows on the substrate. Common sources of contamination include silicone, oil, or water. Most of the defects that occur in applied coatings are not related to the coating manufacturer, a poor formulation or wkh vhohfwlrq ri d zurqj pdwhuldo exw duh shrsoh uhodwhg 7klv lv fdxvhg e\ odfn ri nqrzohgjh odfn ri wudlqlqj and lack of understanding of the consequences of a poorly applied coating.
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