Loc: Florida, USA
Some people love to be different and paint their case a different or a unique color. Nine times out of ten you can tell it was sprayed.
My technique will help you achieve a glass like professional finish.
First lets talk about paint. There are all kinds of paints out there and they are designed to bond to certain applications. When a primer is involved that pretty much goes out the window and you can get away with almost any kind of paint type. However if the application is flexible use a latex paint.
If you want to avoid a primer then use the correct paint type for the application. Acrylic for plastics and ether latex or enamel for metals.
Plastics Say you want to paint a B&W case. Metal frame and plastic panel body. Chances are you want the panels painted and want to leave the metal with that chrome'ish naked look. Remove the panels. Run them in your home's dishwasher. Dry them with a lint free clean rag. Scuff the panels with 600 or 800 grit sand paper. wipe off the panels after sanding with paint thinner. Inspect the panels for deep scratches, cracks and so on. I like to use a epoxy like glue for filling scratches and mending cracks with plastics. It also dries clear and will not bleed though the paint or primer. Fill the scratch and use some thick paper to spread it. Sand it down with 600 or 800 grit so you get the same consistency as the rest of the scuffed panel. clean once again with paint thinner and let it dry.
Applying the paint is a art. I would advise to use a real paint gun for this but if budget mod rings a bell typical spray paint will do. Remember you want a acrylic base paint. If the paint is labeled for plastic then you're good to go.
Hang the panel for better coverage. Laying it on cardboard will make it difficult. This will be a 6 layer process so be in a well ventilated area, powder free gloves and ether a paper mask or a respirator. Applying the first coat is more of a test coat really. This insures the paint is sticking and there is no oil like residue on the panel. Go extremely lite on the first coat moving right to left, kinda like a mist cover. Do the same on the second coat but go at a different direction going up and down. The third coat you can do a medium coat going right to left then the four with a medium up and down. On the fifth coat go with a heavy coat (not to heavy or the paint will run) going right to left and the sixth heavy coat up and down.
Just so you know do coats about five or seven minutes apart on the light and medium and 10 to 15 minutes on the heavy coats.
Since this is plastic and when the paint is dry it will have a dull finish and have the sand like texture. This is where wet sanding comes in.
Let the panels dry overnight.
To wet sand/color sand you need a clean bucket with cool water and a table spoon of soap. I prefer to use car soap but make sure it doesn't have a wax of paint sealant additive. You'll also need two lint free rags. One to soak the panel with water and the other to dry the panel. For the sand paper you'll need 1000 grit and 2000 grit. If you want a glass finish go for the gold and get some 3000 grit sand paper that is used in automotive body work.
soak the 1000 grit paper in the bucket of water. Take the soaked rag and cover the panel in water. Take the soaked sand paper and sand in swirls. Keep dousing the panel with the soaked rag and stop to check the texture. If it's smooth to the touch start on another area. After all of the panels are finished do the exact same thing with the 2000 grit and the 3000 grit. By time you're finished the panels should feel like glass. Dry off the panels and let them sit for 24 hours. you'll notice the finish really looks dull. After the 24 hours it's time to polish and wax. I prefer to use a automotive polish for this and use a bees wax to seal it. This will give it that lush glass finish and also seals the paint so air can not dull the paint again.
Metals Metal is easier to paint but harder to prep. If the metal is naked then you just have to clean it. If it already has a finish I would use a chemical stripper to remove the old finish.
To fix dents, deep scratches and such I would try and repair it by beating out the dent and to conceal scratches use a filling primer. If you use primer you'll be adding an additional sanding step.
You can start buy running the metal in your dish washer or you can use some good old windex and a lint free clean rag. After you clean it handle it with some powder free gloves on so avoid natural oils from your skin getting onto the clean surface. From here you can apply the primer if needed. If primer was used sand it down with 800 grit sand paper. Apply enamel paint the same way that was directed in the plastics portion.
Enamel is a whole different ball game on the finished painting. Let it sit for 24 hours then wet sand is desired with 2000 grit and 3000 grit sand paper then apply a polish and wax to seal it. If you're happy with the non-sanded finish then just apply some polish to flatten the plain and seal it with a wax.
Clear coats You can use a clear coat as a color to keep that natural look of metal. If done right it will look like stainless steel. I don't like adding clear coats on painted surfaces because it dulls the color, but if you want to dull things down a bit then go for it. Applying the clear can be tricky. You want a nice coat but not too heavy or too lite. Just two medium coats should be fine. Sanding the clear isn't needed but some heavy duty polishing will be nice. Bees wax can tarnish the clear but some carnauba is great for clear coats.
Different types of Primers Primers come in different shades of gray and colors. If you're going to paint a light color go for white, if you're going for a medium color go for gray. Dark colors go for dark gray, black or blue. This way if a scratch forms on the color coats the primer will not be as noticeable.
There are also different types of primer grades as well. Primer - Used to cover a surface for painting Build-able Filling Primer - used to fill scratches and is sandable Self-Etching Primer - used to bond to most metals like aluminum and stainless steel. Also works great for fiberglass. It is also sandable.
Touch ups Touch ups can be easy. If you used a automotive paint then chances are there is a touch up pen. If you used regular spray paint like all purpose paint or fusion paint for plastic just spray the paint inside the cap to the can and use a small brush. You'll have to work fast because the paint will dry quickly. If the paint was custom mixed have a copy of the recipe so you can mix more. Custom mixed paint doesn't last long stored since it has a heavy duty harder mixed into it.
Other ways instead of spraying the paint You can use a foam brush, foam roller for painting. Pretty much just like painting a room in your house. However using the brush or roller you'll have more sanding ahead of you.
Chemical strippers Read the directions not once but twice. Wear gloves, a respirator and eye protection all times when using it.
Sanding materials Typical sand paper is always needed but for finer things there always steel-wool, it just doesn't sand the object but also cleans it. I would only use steel wool on metal. Never use it on rubber or plastic.
Treating rubber If you're working on a item that has rubber try and remove the rubber. If you can not remove the rubber then tape it and work around it. Some paints will destroy rubber ether by denigration or dry it out and become brittle. If you want to change the color of the rubber just simply die it. However if it's black rubber live with it.
Final notes Remember, when painting prepping is the key. Takes a long time to prep then to lay down the paint. Takes six hours to prep a standard four door sedan and takes only 20 minutes to paint. So when painting your case just think "good thing this isn't a car".
Great tips, thanks for taking the time to compile such a comprehensive post. It seems like you've done a lot of serious modding over the years.
It's going to be cool to have you modders around, a nice addition to the fray. I like to tear crap apart and put it back together, always have. I've always thought about it, but I think now I am going to build one in the next few months, got the bug now.
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