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jingato
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Group: Forum Members
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+xGelcoat isn't for skinning, it is for making parts from a mould. The blemishes on that small piece look like areas that still have clear coat. Whether they are two spots where the clear coat hasn't been sanded off yet or they are the only two spots where the clear coat has been sanded through - hard to tell from that photo. But you could try to keep sanding them, and see if they get bigger or smaller. If they get smaller, they are remaining clear. If they get bigger, then you have a lot more sanding to do to completely remove the clear. There isn't really a short-cut to achieving perfect results, it takes practise as well as using good materials. Spray cans just won't give you a good finish straight from the can, they will be orange peely. The solution is either to practise sanding and polishing and improve the finish that way, or to get proper spray equipment and use a proper 2k coating that will give you a good finish off the gun. Both of those approaches will require good technique, so there just isn't an option that doesn't involve honing your skills. ah, ok, thank. Gonna keep experimenting with the smaller piece then. I have some new clear coat that I am going to try too. I think I'l sand this one again, clear it, then sand with 2k and polish and see what I get. Thanks!
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bennyT
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Group: Forum Members
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+xGelcoat isn't for skinning, it is for making parts from a mould. The blemishes on that small piece look like areas that still have clear coat. Whether they are two spots where the clear coat hasn't been sanded off yet or they are the only two spots where the clear coat has been sanded through - hard to tell from that photo. But you could try to keep sanding them, and see if they get bigger or smaller. If they get smaller, they are remaining clear. If they get bigger, then you have a lot more sanding to do to completely remove the clear. There isn't really a short-cut to achieving perfect results, it takes practise as well as using good materials. Spray cans just won't give you a good finish straight from the can, they will be orange peely. The solution is either to practise sanding and polishing and improve the finish that way, or to get proper spray equipment and use a proper 2k coating that will give you a good finish off the gun. Both of those approaches will require good technique, so there just isn't an option that doesn't involve honing your skills. Hanaldo, do you use an air fed mask for 2K spraying? I'm led to believe that its dangerous stuff and am currently mulling over whether I will try some 2K spraying myself or just leave it to the professionals. Ben
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Hanaldo
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Group: Forum Members
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+x+xGelcoat isn't for skinning, it is for making parts from a mould. The blemishes on that small piece look like areas that still have clear coat. Whether they are two spots where the clear coat hasn't been sanded off yet or they are the only two spots where the clear coat has been sanded through - hard to tell from that photo. But you could try to keep sanding them, and see if they get bigger or smaller. If they get smaller, they are remaining clear. If they get bigger, then you have a lot more sanding to do to completely remove the clear. There isn't really a short-cut to achieving perfect results, it takes practise as well as using good materials. Spray cans just won't give you a good finish straight from the can, they will be orange peely. The solution is either to practise sanding and polishing and improve the finish that way, or to get proper spray equipment and use a proper 2k coating that will give you a good finish off the gun. Both of those approaches will require good technique, so there just isn't an option that doesn't involve honing your skills. Hanaldo, do you use an air fed mask for 2K spraying? I'm led to believe that its dangerous stuff and am currently mulling over whether I will try some 2K spraying myself or just leave it to the professionals. Ben I do not, I just use a top quality Sundstrom respirator. Mainly because I only have a 2-stage filter on my setup not a 3-stage, so my compressed air isn't breathing quality. That is critical for air-fed masks, you need very good filtration to make the supplied air any safer than the 2k. 2k is definitely nasty stuff, and I wouldn't use it with anything less than a very good quality respirator. But it also depends on your exposure. Air-fed masks are really made as PPE for professional spray painters who spend hours in the booth every day for decades. I do a lot of spray painting, but I probably only average maybe an hour or two a fortnight - though I do have a downdraught spray booth as well, which helps. But for a hobbyist, I feel an air-fed setup will be quite unnecessary. If you have money to burn then go for it, its the best you can get. But if you're looking for something to make it a bit safer to work with every now and then, just get a good quality respirator. Make sure you get something with both A2 organic vapour filters and P2 particulate filters.
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torsten Ker
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Here in Europe 2K hardeners with Isocyanate production or import is banned since 2017 and now mostly phased out and unavailable. Try looking for Non-Isocyanate hardeners with acrylic car paint.
I spray once or twice a month too,using a 3M mask with NOISH approved P100 (60921) filter in a well ventilated room
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jingato
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Group: Forum Members
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Just wanted to give a quick update and also let you guys know about a product I found and used. So I tried the regular spray can clear coat and the orange peel was horrible. I sanded it and got most of it gone, but couldn't get it all. Then polished it and it was ok but not great. I started doing research into 2k clears and I found one, and only one, that is a available in a spray can, since i don't have the equipment otherwise. It's called SprayMax 2K Clear Glamour. Here is a link to their site. You can find it an Amazon, Walmart, or other online retailers to buy. I sprayed it with that and the result was amazing. No orange peel at all. It's as close to a professional spray gun as you are going to get! I gave it a light sanding after and then polished and the final product is a perfect mirror finish! I didn't polish the larger piece yet, but here is the small gas door cover I did so you can see the result  
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beliblisk
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When removing orange peal most of the time you dont need to get it 100% flat (unless you are looking for glass like perfection). Its a pain in the ass to get all sanding marks out anyway so for larger stuff i just level area a bit to remove printrought from postcure and apply 2k UHS clear (and sometimes thats a problem on its own doe to mini pinholes). There is no "best method" and its just a question what gives good finish in as little time as possible. With cf there are a lot of possible ways to address imperfections from manufacturing (small mishaps happen) they just take time and you get better and faster over time  For the record i hate trimming and sanding but uts all part of the job. Keep up the good work 
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Hanaldo
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Group: Forum Members
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+xWhen removing orange peal most of the time you dont need to get it 100% flat (unless you are looking for glass like perfection). Its a pain in the ass to get all sanding marks out anyway so for larger stuff i just level area a bit to remove printrought from postcure and apply 2k UHS clear (and sometimes thats a problem on its own doe to mini pinholes). There is no "best method" and its just a question what gives good finish in as little time as possible. With cf there are a lot of possible ways to address imperfections from manufacturing (small mishaps happen) they just take time and you get better and faster over time For the record i hate trimming and sanding but uts all part of the job. Bang on, agree with all of this - especially the last sentence  I agree with not completely removing the orange peel, as orange peel will actually hide print-through to a degree and can keep the part looking better for longer. A glass flat surface looks unreal at first, but over time as the resin continues to shrink and heat cycles effect the finish, sometimes it is better to have a bit of orange peel to make the surface look more natural and 'intentional'. Obviously it has to be good looking and consistent orange peel though, so good technique and equipment help.
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jingato
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Group: Forum Members
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+xWhen removing orange peal most of the time you dont need to get it 100% flat (unless you are looking for glass like perfection). Its a pain in the ass to get all sanding marks out anyway so for larger stuff i just level area a bit to remove printrought from postcure and apply 2k UHS clear (and sometimes thats a problem on its own doe to mini pinholes). There is no "best method" and its just a question what gives good finish in as little time as possible. With cf there are a lot of possible ways to address imperfections from manufacturing (small mishaps happen) they just take time and you get better and faster over time For the record i hate trimming and sanding but uts all part of the job. Keep up the good work Holy crap, that looks ridiculous. I literally was looking at it for at least a minute trying to understand why you posted an image of a shed door. I didn't even realize that the cf part was there because it looked like a mirror with some shadows. Impressive work. What is print-through anyway?
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Hanaldo
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Print-through is an effect you get in composites as a result of the shrinkage of the resin. All resins shrink as they cure, and for the most part that occurs in the mould while the surface is supported. But after demoulding the resin continues to shrink a little more, and now the surface is unsupported - so the surface loses its flatness fibres start to become visible in the resin, 'printing' onto the surface. If the part is exposed to higher temperatures than it was cured at, such as sitting in the sun, then the resin will soften and it will print.
The effect is worse in low resin content processes like infusion and pre-preg, because there is less resin for the fibres to 'float' in. It is especially bad when you have cores or other things in the layup that cause a small degree of bridging where the resin pools and shrinks more, and you end up with the shape of the core or whatever is embedded in the layup printing onto the surface as well.
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Warren (Staff)
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Also worth waiting until the part has been post cured before doing any finishing work as the post curing process itself can cause a bit more print due to shrink back. Post curing in the mould will reduce that and reduce the chance of distortion, but it is always very hard to get a perfect finish.
Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant
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