eBay rear fins. paint fail
02-08-2019, 05:27 PM
#1
Drifting
Thread Starter
eBay rear fins. paint fail
I bought the eBay rear defuser fins trying to save some money and to simply do it myself. I bought a set of 12 ounce Flash Metallic paint and clear coat combo. I sanded the shinny ABS plastic fins with 100, 400, 800, then 2000 sandpaper. Make a long story short, after another set of paints, 24 ounces, my project looks like crap. Absolute crap. What is it with modern rattle can paint? I can’t get the finish smooth. I’m painting in the sun at about 72 degrees. I give up and will take them to my body shop to paint for me. In the end, it may cost more that the ACS painted parts at close to $400. Has anyone else tried to paint these fins with rattle cans?
02-09-2019, 11:58 AM
#2
Every post/article I read that uses rattle can paint seems to be in a different dimension when it comes to how the finished product looks. In my experience rattle can paint is excellent to make something a different color. If you want it to look good closeup rattle can paint isn't the right product.
02-09-2019, 02:06 PM
#3
Drifting
I have had excellent results with the Krylon brand paint that contains paint and primer together, but my use has been limited to hobby projects.
02-09-2019, 02:31 PM
#4
Drifting
Thread Starter
I’ve painted things with rattle cans since I was 11 years old. I’m 62 now. I’ve been successful for years with this kind of thing. Either paint has changed or I’m too old! Lol. I won’t mount anything that isn’t perfect on my 19 Grand Sport. Oh well. I’ll have them painted professionally. Of course, I didn’t mention that I have a body shop as my tenant. I just have always done this kind of thing myself. Oh well. Is what it is.
02-09-2019, 06:16 PM
#7
Safety Car
Did you use any plastic adhesion promoter or some kind of plastic primer? I would have guessed sanding would be enough but maybe not.
02-09-2019, 06:44 PM
#9
Drifting
Thread Starter
I didn’t prime. Maybe that was my problem. I used the 2000 grit before I painted. Then I used the 2000 to lightly sand the clear coat. Then I used a light compound to polish. Just didn’t turn out well. Again, looks like crap!
02-10-2019, 01:58 AM
#11
Drifting
I agree. 2000 is for prepping clear coats for polishing. Even for that task it's too fine if the goal is to smooth out orange peel; it's mainly for knocking out lint. 1000 is fine enough--take the 1000 and roll it on itself- don't fold a crease into it, but *very* lightly roll it over against itself and rub it together to knock out the sharpest abrasives.
Now for prep, 600 is as fine as I'd allow. I'd recommend a new sheet of 400. Your problem could be the ambient temperature, the distance from the surface at which you held the can, and the speed you moved your hand as you sprayed. If you want a lot of "shine", the paint has to be smooth. There's two ways to accomplish that--clear coat the hell out of project and then sand it smooth so's you can polish it, or paint it in cooler weather with experience on the paint's flash time...
Paints in rattle cans can't be chemically "controlled" by the buyer. Whatever the manufacturer injected into the can is what you have to work with. "Paint" is essentially made up of two parts (for this discussion)-- the color, and its' "solvent"--the chemical that allows it to remain liquid in order for the air supply to spray it. Professional painters gear their choice of "solvent" according to the ambient temperature. I might be a little behind the times because I painted professionally 30 years ago, but the process hasn't changed, though the nomenclature and chemicals might have.
If we want a smoother color, we have to allow the solvent dry slowly, which allows the paint to flow out on the surface. The faster it dries, the less time the paint has to lay out smoothly. (think of pouring water onto a large metal panel at 60*--it runs everywhere; now think of the metal panel at 28* because the ambient air is 28*--the water won't "lay out" and "flow", it'll freeze almost on contact--like paint on a hot day (72*) applied to a 72* panel. You can vary the drying time by the distance you spray from your painted surface-- AND by the speed with which you spray. The farther away you are, the more orange peel you "freeze" into the surface because the solvents are evaporating between the can and the surface as you spray. You can see different results if you move closer, thereby increasing the amount of paint and solvent applied over the same area--that closeness allows more solvents to remain "in solution" as the paint contacts the panel. Alternatively, the slower you go (even at the same distance), the more paint/solvent is applied over the given area, allowing for the mass of solvent to evaporate slower which allows the color to lay out smoother.
72* could well be too warm for the can's solvent. 50-59* is probably too cold (it all depends on the OEM solvent in the can); the moisture in the air would cause a phenomenon called "blushing"--as if you clear-coated a breath-frosted windshield on a cold day. However, 60-65* should be cool enough to let the can's solvent stay "in solution" long enough to let the paint lay down.
As you can see, there's no "one-choice" answer to your problem--your poor results (no insult intended) were probably a combination of several factors--distance you shot the paint from the surface, how fast or slowly you moved as you sprayed, and the temperature. If I was to shoot in 72* weather, I'd be close to the work moving at a medium speed--not an easy concept (in my mind, to establish "medium" speed) considering I don't know what solvent is in the can. It'd have to be trial and error. Find you a piece of plastic to practice on--something large enough to force you to pay attention to your distance and speed of movement. The side of a plastic 5-gallon drum (square is better for practicing for a novice [no offense intended]--a round can requires much more practice to maintain a constant distance as you move around the can) or a Rubbermaid garbage can, etc. Sand whatever you choose with 400 grit (wet) until the surface is smooth and practice on it. When you know how slowly you have to move combined with your can's distance from the surface in order to obtain a glossly, smoothly painted surface (after it's dried), then you can go back and spray can your project. Otherwise, it's all guess work. You'd be paying a pro for his knowledge of distance, speed of movement, and chemical reaction to temperature. He'll probably use a catalyzed paint though, and the catalyst ("epoxy" reactor that hardens the paint [to the point we call "dry]) will be his choice according to temp. You can accomplish the same thing for very small parts that aren't that visible for a lot less with some patience and maybe the cost of 2-3 rattle cans at most.
I forgot to add--I'm not sure you can spray enough clear coat on to sand it down to smooth--rattle can paints are so thin. There's nothing to lose by trying, and since you've gotten to the clear coat stage this would probably be the shortest alternative, but I'd load the HELL out of the clear coat--15-20 coats so you could sand it with 1000 wet. If it was out of a regular spray gun, 2-3 coats would be the norm.
Now for prep, 600 is as fine as I'd allow. I'd recommend a new sheet of 400. Your problem could be the ambient temperature, the distance from the surface at which you held the can, and the speed you moved your hand as you sprayed. If you want a lot of "shine", the paint has to be smooth. There's two ways to accomplish that--clear coat the hell out of project and then sand it smooth so's you can polish it, or paint it in cooler weather with experience on the paint's flash time...
Paints in rattle cans can't be chemically "controlled" by the buyer. Whatever the manufacturer injected into the can is what you have to work with. "Paint" is essentially made up of two parts (for this discussion)-- the color, and its' "solvent"--the chemical that allows it to remain liquid in order for the air supply to spray it. Professional painters gear their choice of "solvent" according to the ambient temperature. I might be a little behind the times because I painted professionally 30 years ago, but the process hasn't changed, though the nomenclature and chemicals might have.
If we want a smoother color, we have to allow the solvent dry slowly, which allows the paint to flow out on the surface. The faster it dries, the less time the paint has to lay out smoothly. (think of pouring water onto a large metal panel at 60*--it runs everywhere; now think of the metal panel at 28* because the ambient air is 28*--the water won't "lay out" and "flow", it'll freeze almost on contact--like paint on a hot day (72*) applied to a 72* panel. You can vary the drying time by the distance you spray from your painted surface-- AND by the speed with which you spray. The farther away you are, the more orange peel you "freeze" into the surface because the solvents are evaporating between the can and the surface as you spray. You can see different results if you move closer, thereby increasing the amount of paint and solvent applied over the same area--that closeness allows more solvents to remain "in solution" as the paint contacts the panel. Alternatively, the slower you go (even at the same distance), the more paint/solvent is applied over the given area, allowing for the mass of solvent to evaporate slower which allows the color to lay out smoother.
72* could well be too warm for the can's solvent. 50-59* is probably too cold (it all depends on the OEM solvent in the can); the moisture in the air would cause a phenomenon called "blushing"--as if you clear-coated a breath-frosted windshield on a cold day. However, 60-65* should be cool enough to let the can's solvent stay "in solution" long enough to let the paint lay down.
As you can see, there's no "one-choice" answer to your problem--your poor results (no insult intended) were probably a combination of several factors--distance you shot the paint from the surface, how fast or slowly you moved as you sprayed, and the temperature. If I was to shoot in 72* weather, I'd be close to the work moving at a medium speed--not an easy concept (in my mind, to establish "medium" speed) considering I don't know what solvent is in the can. It'd have to be trial and error. Find you a piece of plastic to practice on--something large enough to force you to pay attention to your distance and speed of movement. The side of a plastic 5-gallon drum (square is better for practicing for a novice [no offense intended]--a round can requires much more practice to maintain a constant distance as you move around the can) or a Rubbermaid garbage can, etc. Sand whatever you choose with 400 grit (wet) until the surface is smooth and practice on it. When you know how slowly you have to move combined with your can's distance from the surface in order to obtain a glossly, smoothly painted surface (after it's dried), then you can go back and spray can your project. Otherwise, it's all guess work. You'd be paying a pro for his knowledge of distance, speed of movement, and chemical reaction to temperature. He'll probably use a catalyzed paint though, and the catalyst ("epoxy" reactor that hardens the paint [to the point we call "dry]) will be his choice according to temp. You can accomplish the same thing for very small parts that aren't that visible for a lot less with some patience and maybe the cost of 2-3 rattle cans at most.
I forgot to add--I'm not sure you can spray enough clear coat on to sand it down to smooth--rattle can paints are so thin. There's nothing to lose by trying, and since you've gotten to the clear coat stage this would probably be the shortest alternative, but I'd load the HELL out of the clear coat--15-20 coats so you could sand it with 1000 wet. If it was out of a regular spray gun, 2-3 coats would be the norm.
Last edited by dork; 02-10-2019 at 10:17 AM.
02-10-2019, 12:24 PM
#12
Drifting
Thread Starter
I agree. 2000 is for prepping clear coats for polishing. Even for that task it's too fine if the goal is to smooth out orange peel; it's mainly for knocking out lint. 1000 is fine enough--take the 1000 and roll it on itself- don't fold a crease into it, but *very* lightly roll it over against itself and rub it together to knock out the sharpest abrasives.
Now for prep, 600 is as fine as I'd allow. I'd recommend a new sheet of 400. Your problem could be the ambient temperature, the distance from the surface at which you held the can, and the speed you moved your hand as you sprayed. If you want a lot of "shine", the paint has to be smooth. There's two ways to accomplish that--clear coat the hell out of project and then sand it smooth so's you can polish it, or paint it in cooler weather with experience on the paint's flash time...
Paints in rattle cans can't be chemically "controlled" by the buyer. Whatever the manufacturer injected into the can is what you have to work with. "Paint" is essentially made up of two parts (for this discussion)-- the color, and its' "solvent"--the chemical that allows it to remain liquid in order for the air supply to spray it. Professional painters gear their choice of "solvent" according to the ambient temperature. I might be a little behind the times because I painted professionally 30 years ago, but the process hasn't changed, though the nomenclature and chemicals might have.
If we want a smoother color, we have to allow the solvent dry slowly, which allows the paint to flow out on the surface. The faster it dries, the less time the paint has to lay out smoothly. (think of pouring water onto a large metal panel at 60*--it runs everywhere; now think of the metal panel at 28* because the ambient air is 28*--the water won't "lay out" and "flow", it'll freeze almost on contact--like paint on a hot day (72*) applied to a 72* panel. You can vary the drying time by the distance you spray from your painted surface-- AND by the speed with which you spray. The farther away you are, the more orange peel you "freeze" into the surface because the solvents are evaporating between the can and the surface as you spray. You can see different results if you move closer, thereby increasing the amount of paint and solvent applied over the same area--that closeness allows more solvents to remain "in solution" as the paint contacts the panel. Alternatively, the slower you go (even at the same distance), the more paint/solvent is applied over the given area, allowing for the mass of solvent to evaporate slower which allows the color to lay out smoother.
72* could well be too warm for the can's solvent. 50-59* is probably too cold (it all depends on the OEM solvent in the can); the moisture in the air would cause a phenomenon called "blushing"--as if you clear-coated a breath-frosted windshield on a cold day. However, 60-65* should be cool enough to let the can's solvent stay "in solution" long enough to let the paint lay down.
As you can see, there's no "one-choice" answer to your problem--your poor results (no insult intended) were probably a combination of several factors--distance you shot the paint from the surface, how fast or slowly you moved as you sprayed, and the temperature. If I was to shoot in 72* weather, I'd be close to the work moving at a medium speed--not an easy concept (in my mind, to establish "medium" speed) considering I don't know what solvent is in the can. It'd have to be trial and error. Find you a piece of plastic to practice on--something large enough to force you to pay attention to your distance and speed of movement. The side of a plastic 5-gallon drum (square is better for practicing for a novice [no offense intended]--a round can requires much more practice to maintain a constant distance as you move around the can) or a Rubbermaid garbage can, etc. Sand whatever you choose with 400 grit (wet) until the surface is smooth and practice on it. When you know how slowly you have to move combined with your can's distance from the surface in order to obtain a glossly, smoothly painted surface (after it's dried), then you can go back and spray can your project. Otherwise, it's all guess work. You'd be paying a pro for his knowledge of distance, speed of movement, and chemical reaction to temperature. He'll probably use a catalyzed paint though, and the catalyst ("epoxy" reactor that hardens the paint [to the point we call "dry]) will be his choice according to temp. You can accomplish the same thing for very small parts that aren't that visible for a lot less with some patience and maybe the cost of 2-3 rattle cans at most.
I forgot to add--I'm not sure you can spray enough clear coat on to sand it down to smooth--rattle can paints are so thin. There's nothing to lose by trying, and since you've gotten to the clear coat stage this would probably be the shortest alternative, but I'd load the HELL out of the clear coat--15-20 coats so you could sand it with 1000 wet. If it was out of a regular spray gun, 2-3 coats would be the norm.
Now for prep, 600 is as fine as I'd allow. I'd recommend a new sheet of 400. Your problem could be the ambient temperature, the distance from the surface at which you held the can, and the speed you moved your hand as you sprayed. If you want a lot of "shine", the paint has to be smooth. There's two ways to accomplish that--clear coat the hell out of project and then sand it smooth so's you can polish it, or paint it in cooler weather with experience on the paint's flash time...
Paints in rattle cans can't be chemically "controlled" by the buyer. Whatever the manufacturer injected into the can is what you have to work with. "Paint" is essentially made up of two parts (for this discussion)-- the color, and its' "solvent"--the chemical that allows it to remain liquid in order for the air supply to spray it. Professional painters gear their choice of "solvent" according to the ambient temperature. I might be a little behind the times because I painted professionally 30 years ago, but the process hasn't changed, though the nomenclature and chemicals might have.
If we want a smoother color, we have to allow the solvent dry slowly, which allows the paint to flow out on the surface. The faster it dries, the less time the paint has to lay out smoothly. (think of pouring water onto a large metal panel at 60*--it runs everywhere; now think of the metal panel at 28* because the ambient air is 28*--the water won't "lay out" and "flow", it'll freeze almost on contact--like paint on a hot day (72*) applied to a 72* panel. You can vary the drying time by the distance you spray from your painted surface-- AND by the speed with which you spray. The farther away you are, the more orange peel you "freeze" into the surface because the solvents are evaporating between the can and the surface as you spray. You can see different results if you move closer, thereby increasing the amount of paint and solvent applied over the same area--that closeness allows more solvents to remain "in solution" as the paint contacts the panel. Alternatively, the slower you go (even at the same distance), the more paint/solvent is applied over the given area, allowing for the mass of solvent to evaporate slower which allows the color to lay out smoother.
72* could well be too warm for the can's solvent. 50-59* is probably too cold (it all depends on the OEM solvent in the can); the moisture in the air would cause a phenomenon called "blushing"--as if you clear-coated a breath-frosted windshield on a cold day. However, 60-65* should be cool enough to let the can's solvent stay "in solution" long enough to let the paint lay down.
As you can see, there's no "one-choice" answer to your problem--your poor results (no insult intended) were probably a combination of several factors--distance you shot the paint from the surface, how fast or slowly you moved as you sprayed, and the temperature. If I was to shoot in 72* weather, I'd be close to the work moving at a medium speed--not an easy concept (in my mind, to establish "medium" speed) considering I don't know what solvent is in the can. It'd have to be trial and error. Find you a piece of plastic to practice on--something large enough to force you to pay attention to your distance and speed of movement. The side of a plastic 5-gallon drum (square is better for practicing for a novice [no offense intended]--a round can requires much more practice to maintain a constant distance as you move around the can) or a Rubbermaid garbage can, etc. Sand whatever you choose with 400 grit (wet) until the surface is smooth and practice on it. When you know how slowly you have to move combined with your can's distance from the surface in order to obtain a glossly, smoothly painted surface (after it's dried), then you can go back and spray can your project. Otherwise, it's all guess work. You'd be paying a pro for his knowledge of distance, speed of movement, and chemical reaction to temperature. He'll probably use a catalyzed paint though, and the catalyst ("epoxy" reactor that hardens the paint [to the point we call "dry]) will be his choice according to temp. You can accomplish the same thing for very small parts that aren't that visible for a lot less with some patience and maybe the cost of 2-3 rattle cans at most.
I forgot to add--I'm not sure you can spray enough clear coat on to sand it down to smooth--rattle can paints are so thin. There's nothing to lose by trying, and since you've gotten to the clear coat stage this would probably be the shortest alternative, but I'd load the HELL out of the clear coat--15-20 coats so you could sand it with 1000 wet. If it was out of a regular spray gun, 2-3 coats would be the norm.
But, you sure pointed out a number of possible reasons I failed on the fins. Thanks for that. I’ll take them in and have them professionally painted. Ya can’t mount crap on a new 75k car! Needs to be perfect. Thanks again....
02-10-2019, 01:04 PM
#13
Drifting
Nope. Just no experience or knowledge. ANY rattle can will need a spare for practice, especially for an application like "professional results" for vehicles--these surfaces are so smooth to start with, there's less room for error. It can be done, it just takes practice. You're welcome!
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vetten76 (02-10-2019)
02-11-2019, 02:35 PM
#14
Racer
If you used a standard over the counter rattle can clear, this is the majority of the issue. They do not have a hardener in them and are left to cure in environmental conditions which obviously fluctuate all the time. In the future, try the 2 part clear (2K) I have always had luck with it. Once you puncture the inner chamber for the hardener to mix, you only have a limited time to use it. Best I have gotten was 1 day before the can was useless but the results were great. Use a mask.... trust me.
2K Clear
How To Vid
2K Clear
How To Vid
02-12-2019, 07:22 PM
#15
Race Director
Member Since: Mar 2001
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I don't know what your are doing with your paint, but I can say that you are sanding way too finely for good paint adhesion! Stop at 400 or 600--at the very finest. I'd have to watch you painting to see what else is at issue. All the best.
Last edited by Avanti; 02-12-2019 at 07:23 PM.