clear coar over colour coat

[FrankM83]

Hi all,
would like to know if the colour coat should be sanded down before giving the clear coat on a metallic paint? Thanks

[Rich_T]

Hi, No, once the basecoat is applied its ready to take the clearcoat. Depending how long youve left it before clearcoating you may want to tack it off if dust's settled on it, however be very gentle when doing this.
Rich

[FrankM83]

thanks, also if the first coat is not satisfactory can I sand this down and give it another coat of clear? Thanks

[Rich_T]

go for 2 coats at least of clear coat, any inperfections can be flatted (1200g wet & dry) out and polished up (even with 2k laquer). If you still feel you want to go with another coat then flat out your imperfections and then prepare the rest with a grey Scotch pad (looks like a scouring pad). Hope that helps
Rich

[FrankM83]

thanks for all the help, my imperfections is some parts of the fender came out glossy and other parts a bit matt or less glossy can you tell me why please? thanks

[Rich_T]

I would guess (without seeing it) that it was to do with how much laquer you got on. Minor wings arent the easiest to paint so whats probably happened is that the glossy bits have had full coverage hence the shine and the dull parts have been passed over with the gun to quickly leaving dry patches. Try and get a good coverage, keeping the gun the same distance from the panel. You should be able to see when painting which parts are looking dull, go back and take a second pass over them so that the wing appears to have a uniform finish. Dont worry about getting to much laquer on (within reason) as its easier to flat a run out than polish up a dry section.
Rich

[jonathon]

The first coat of lacquer is used as a hanger /gripper coat, and may well look very dry and orange peely. The second coat should be applied wet, and this will re activate the first coat giving a good chemical bond and also a smoother surface. A third coat can then be applied and if you wish add just a small percentage more thinners to help the coat to flow out. You must always leave at least 20 mins for flash off, between coats this allows the solvents to be released into the atmosphere, failure to do so will eventually result in solvent pop which is where the solvent breaks through the final layer in small blisters.
The shiny and dull areas might also be in the base coat. This should be applied as light as possible to allow the correct alignment of the metalics, too wet and you will get a flat appearance too dry and you will see stripes in the paint. You also need to avoid getting too close to the panel ,as Rich states you need to spray at a constant speed and distance to the panel. Always hang the panel and spray it as it will be seen on the car, ie spray the wing side to side from top to bottom. do not spray it vertically. If spraying in an unheated booth or garage the times for flash off should be doubled. Also do not leave the base coat any longer than about 6 hours before applying the lacquer. If you do then you will need to spray on another layer of base coat first.