OK boys and girls, I'm going to chat about cutting and buffing the paint job on your car, this subject is touchy with a lot of people, who think that this step in unnecessary, and this would of course depend on what you want the car to look like when it's completed, a cut and buffed paint job looks completely different from a non cut and buffed paint job, and yes there is a significant risk to your paint job if the person who's doing the cutting and buffing has no experience with the process, it can devastate your new paint job, and you don't need to re-paint your car, so be sure that they know what they are doing.
The first step after you pull the car out of the paint booth should be to unmask it, and then I suggest re-masking the car with clean masking paper, but you don't really need to do this if you don't want to, cleaning the buffing compound off of the car will be a lot harder if you don't mask it again, it just kind of depends on were you want to spend your time, in my opinion it should always be done.
Now that we have that out of the way, before yo mask the car you should wash it, and then blow it off with compressed air to remove the excess water, the car can't be clean enough before you do this step, now before I explain to you the process of cutting and buffing, I'm going to explain the draw backs of cutting and buffing the car, the reasons why a lot of people don't like to do it.
1. The potential to damage your new paint job, there are two big reasons why some people shy away from this step, the first reason is that an inexperienced person color sanding the car may go through the clear coat of the paint and in to the color coat, and this means a paint repair on that area where they went through, or a total re-paint of the car "Not Good", the second reason would be that if they don't go through the base coat of the paint there is a chance that the buffer can burn the paint job, when I was learning, I had both of these things happen to me, and neither one of them are fun to fix.
2. Is the extra time that it takes to do the cutting and buffing of the car, this can be up to 20 hours of added time, if your one of those people who is always in a hurry, then it's obvious why you'd hate this process, you absolutely cannot be in a hurry, or those bead things that I talked about earlier with without a doubt happen.
The reason why I like the paint job cut and buffed is for the look, it looks completely different from a non-buffed car, the non-buffed car will look great, don't get me wrong here, it will have a factory looking paint job, with an ultra shine, and it will be absolutely brilliant in the sun light, but will appear that the color is on top of the paint job, as where a buffed car will look deep, like you could stick your hand in the paint and swirl it around, the decision is all yours, but I will say that if you decide to cut and buff the car, make 100% sure that the people doing the work know what they are doing.
Look at some of their work to determine if you want this done, there are a lot of shops that have this down to a science, and you don't need to worry at all if you find the right people, that being said, this is not a step that I think a beginner should attempt, although I'm about to explain the process, if you feel confident, then go ahead and give it a try.
The Color Sanding Process:
After the car has been re-masked, you should get a bucket with water and dish soap in it, or if you feel more at home using a spray bottle load it with water and dish soap also, and then your going to want to have some 1000 grit wet sand paper to start with, and you'll be working up to 2000 grit by the time this process is done, first you'll need to spray the car down with water, and it does not matter where you start to color sand the car, it's just where you feel comfortable starting from, this is a long process, so don't get in a hurry, if you do it will be at the expense of you new paint job, OK now you'll want to have a decent selection of sanding blocks, a cut and buff is designed to create a smooth appearance over the entire surface of the car, and if it's done right it does a very good job of that.
Now that you have sprayed the car down with water load up your 1000 grit wet sand paper on a sanding block, I usually use a 6" hard flat block on the large flat surfaces of the car, you never want to sand or buff the crown of any panel on your car, I use a 6" round hard rubber block in the curved areas on the panels, at the first it will look as if it's not doing anything, but take my word it is smoothing the clear coat on your car, when you color sand you clear coat you need to pay serious attention to what you are doing, cutting and buffing will remove any dust or runs from you paint job and smooth the surface to a brilliant deep shine.
When you start to sand the car, if your using a spray bottle you'll spray some of the contents from the bottle on to your painted surface, and then you'll begin to sand the clear coat with 1000 grit wet paper, make sure that you sand only in one direction, as it will be easier to buff out in the end, do not press hard on the block, let the sand paper do the work, and if you hear a squeaking sound stop now, and run some water over your sanding block and the surface of the car, a squeaking sound means that you have a piece of balled up clear coat under the block, or dirt, in either case, you do not want it there so clean the block and surface of the car.
When your sanding your paint with the 1000 grit paper, your looking for the entire surface of the car to have a smooth and dull appearance, remember that you still have to sand the clear coat with 1500 and 2000 grit sand paper, so it does not need to be perfect at this stage of the game, just make sure that you've sanded the entire surface of the car before you move on to the next stage.
Now you'll repeat the same process with 1500 grit wet paper, and then 2000 grit wet paper, after you have done this, you done color sanding or cutting the clear coat, during this process yo don't ever want to see the color of your base coat on the sanding block, this means that you have gone through the clear coat, so pay attention to what you are doing.
The Buffing Process:
Now that the cutting or color sanding process is complete on your car, you'll want to wash all the wet sanding residue from the car, wet sanding will leave a with powder type residue on the car, and you don't want to put the buffer to this residue, so make sure that you wash the entire car again before you get started with the buffer.
Now let's get the buffer out and set the speed to about 800 rpm or medium speed on the speed selector, this may seem a bit slow, but you have less of a chance of burning the paint job with it set at a lower speed, and you can use water to help cool the paint as you buff the car if you want to, you'll be starting with a heavy buffing compound and working all the way down to a swirl remover, yet another long process.
Get you courage up and your patience, and get ready to dive in head first, there is no changing your mind now.
Now put a little dab of the heavy cutting compound on the surface of the car where you want to start buffing the paint, and also I almost forgot, this needs to be done inside a garage, the sun will cause big problem with this process, what your going to do is put a wool pad on the buffer, and then pull the buffer trigger and begin to buff the heavy cutting compound off of the car, you'll notice it starting to bring the shine up on the surface of the paint, when you run out of the heavy compound on the surface just keep adding more and moving in slow circular motions until the entire surface is buffed with the heavy compound.
You'll repeat this process with medium cutting compound, and then light compound, and last but not least swirl remover.
When you change compounds you'll want to have the appropriate foam pads for each step in the process, and make sure that you clean all the pads as they will get clogged with compound, you can can a pad cleaning tool from your local auto paint retailer.
I've been in the automotive business for about 20 or 25 years, I have worked in all facets of the industry, from parts to restoration, all different makes and models, I just want to keep people interested in the old cars because it's where my heart is.