All of the information that follows comes from research,ie reading and speaking with professionals as well as actually doing.
You will probably find that it is easier and less expensive than you think to paint your own bike.
The only thing I stress more than anything is paying attention to what you are doing and completing the steps to a "T". If you do this, you can paint your bike in a day with a quality finish.
There are three ways to paint your bike.
The first, is using spray paint out of a can. You would be surprised at how good it looks if you use the right paint and do a good sanding job.
The second, is using automotive paint. Use this if your interested in painting your bike several times or want to paint other peoples bikes for money.
The third, is powdering coating. This is where you use an electrical current to draw the paint to the surface you want painted.
I have never attempted this before, but I have heard everyone rave about it. The only drawback is you have build a piece of equipment to bake the finish onto the bike. Which I will explain futhure later.
Systems
*I left out spray can painting because everyone knows where to get it. Just follow the sanding instructions for automotive paint and use a acrilyc laquer based paint. The acrilyc laquer paint gives a tougher finish.
Automotive Paint
If you opt for automotive paint or powder coating you can get the equipnent you need from places like the JC Whitney or The Harbour Frieght Co. catalogue. Both are discount online industrial tool sales companies. You could also go to your hardware or auto store. Both places sell HLVP paint guns for cheap. When I say cheap I mean cheap betweem $50-$90. That is cheap. They even make a two in one air compressor and gun system that goes for $125-$150. this will do the trick. You can buy and HVLP touch up spray gun, which is good for painting frames because it is a little smaller. I've seen spray gun/touch up gun packages with all the fixings for $100.00 at hardware store. That is crazy cheap.
If you want a seperate compressor you can buy one for $150-$300 probably even cheaper if you look hard enough. If you do go this route there are some things you have to make sure of. One make sure the compressor you buy supports the output (CFM) of your gun. CFM stands for Cubic Feet Per Minute. Thats all you need to know. Just make sure your compressor can push more or an even amount of CFMs than your gun can. Find a sales person, tell him what paint you are trying to shoot through the gun. He or she will be able to point you in the right direction.
Buy all the paint supplies at an automotive body finishing supplier. You'll need metal conditioner, sandable ecthcing primer, base coat color and a clear coat.
The etching primer is a must, because no paint will stick to aluminum without it. Etching primer microscopically bites into the aluminum, bonding the paint to the frame and is used in place of, or in conjunction with regular primer.
The metal conditioner cleans the grease and other impurities from the surface of the frame. It also has an etching effect as well. Read the directions for water dilultion amount. I use Dupont's Metal Conditioner 5717s.
Base color. Buy the paint in half quart quantities. It's all you'll need unless you are painting a tandem bike. Paint starts at $60 a half quart. I use Dupont's Chromasystem paint because it had good colors. I know nothing about any other systems and I do not work for Dupont. Tell the sales person what you are trying to paint and what steps you are doing it in. They hook you up with color charts and so forth.
You need a "Basemaker" which goes directly into the paint for Duponts Chromasystem. A basemaker controls the curing of the paint by temperature. Depending on if you pick low or high temp the faster or slower the paint will dry. This might differ from system to system.
Clear coat again ask your sales person which clear coat is compatible with your system.
You will have enough clear coat and basemaker to do a couple of bikes so don't freak if you spend $70-$80 on just those two thiings.
The etching primer usally comes in spray paint cans or gallon containers. Gallon containers of etching primer run about $70.00 -$150.00 , spray cans run $7.00 at an auto store.
Note: The intial output for using automotive paint runs $200.00 -$500.00 depending on which equipment you choose. Once that is done all your payig for is paint and supplies.
I checked around most places that paint frames. They start charging at about $175.00 - 300.00 then start charging you $25 for each decal position. You would probably spend a good $300-400 after if you include shipping and any other wierd little charge they throw at you.
So buying your own equipment might be worth the money. You could turnaround and charge people you know for painting there bikes and make a little cash. Once you paint your first bike you get the bug. It is kind of fun seeing something in it's raw form go to a finished product.
Powder Coating
If you go with powder coating you have to buy the console they sell. I have seen if for $150.0.0 at Harbour Frieght.
Powder coating is good because there is less mess invovled. The paint comes in a powdered form and stays that way until it cures.
The only drawback is that powder coating needs to be baked on. So you will have to build a heatbox for curing the paint.
An Infared heating system works good for this. Infared heats from the inside out, bonding the paint to the frame better. You can buy infared space heater elements from Harbour Frieght inexspensively and then "Mcguyver" a heat box out of wood and sheet metal.
Do a little research on the web on how long your painted frame will take to cure and you have a clean, cheap and efficeint way to paint your frame.
I hear people say that powder coating has a tuffer finish then other finishing processes.
The Process of Painting a Frame
1. Stripping the Bike
Use a paint stripper called (Tal-Strip). It's used in the automotive and aviation industries to remove paint. it will take the paint off in about 15-20 minutes with not much effort. You can get it from your local hardware store in the stains and paint remover section. Nothing works as good as this stuff does and it's water soluable.
How you use it
Wear a pair of gloves, it will burn if you touch it with unprotected skin. Paint Tal-Strip onto the frame with a brush. Make sure you cover every inch of the frame including the angled areas. Brush on a thick coat of it so you won't have repeat the same step. The directions say wait 15-20 minutes for the action of the chemical to take affect. I let it sit for about an hour so. This lets all of the tal-strip dry up and all that is left if paint flaking of the frame. Plus it's eaisier to clean up when the chemical is dried up. Scrap any remaing paint flake off with a plastic paint scraper. Hose off any remaining chemical from the frame.
2. Preparing the frame to Accept Paint
Use a metal conditioner diluted with water in a spray bottle. Spray a good amount all over the frame. Wear clean rubber glove so you don't add any grease from your hand to the frame. Let the solution sit on the frame for a couple of minutes then hose off with water until theres no solution remaining on the frame. You will be able to tell because the frame will no longer be slippery to the touch.
Once the frame is clean of the solution, blow out all of the nokes and crannies with canned air or an air compressor. Make sure you do a good job of blowing out all the water. Water will sneak out of places you thought you got, just when your laying down your primer ruining the finish.
I usally blow out the crannies and then hang the frame upside - down with the seatpost tube inlet facing the floor to allow for water that got into the frame to leak out. For best results stick it in the sun for an hour or so, just to be sure. Now your ready to shoot paint.
3. Shooting the Primer and Paint
1. Priming the Frame for Paint
Some frames are made of metals that require an ecthing primer. Aluminum frames most definatly will need to be coated with an etching primer. Otherwise paint would not adhere to it's surface. I have never painted a titanium or a carbon fiber bike before. So, I couldn't tell you if etching primer is safe to use or not. You'll have to call the frame company to find out.
2. You will have to figure out a way to hang you frame for painting.
You could hang it by using a rubber stopper with a screw and bolt going through it. Shove the rubber stopper into the seatpost tube. Enough so it clears the edge of the tube. Then attach a hanger to the screw or whatever you have designed in it's place (the screw was used to give a genral idea).
Hangers are good because they keep their rigidity. You don't want the frame twirling around on you while you paint. The pressure from the spray gun will move it all about if you don't keep it somewhat rigid. This will make it difficult to keep the paint coverage even and give you a genral sense of grief all around.
I use a bike stand,wth a small piece of cloth on the bottom end of a seat post and shove it into the seatpost tube. This genrally creates enough of grip that the seat post will not turn in any direction unless I want it to. Use an old seat post or tape up the one you use.
Once the seat post is in place, I place the bike in the stand by the seatpost and turn the bike upside down. This allows for access to each side of the bike with out having to move it. Quciker access allows me to be more fluid in my painting. Rather than having to stop at one side to turn the bike around, I move myself around it. Being fluid while painting helps keep proper paint coverage. Try to go with the flow of the frame you don't want to stop painting when you are using a spray gun.
3. Once the frame is hung you are ready to paint.
Before I lay any paint on the frame I blow it off one more time with an air compressor. This gets some of the dust off the frame. You will be painting outside so you'll be affected by everything that is outside.
If dust becomes a real issue paint the frame in a camping tent. But wear a mask and gogles if you paint in the tent. Paint gets in to everything even your eyes and all your skin. If you use the automotive paint for a long time without proper protection I have heard you turn into a real zombie from all the paint that accumalates in your body.
4. Get your etching primer and your spray gun ready.
Test the flow and eveness of the paint coming through the gun on some cardboard or something metal that resembles the metal you are about to paint on.
You can set the amount of paint flow and the speed at which it comes out of the needle on your gun. Your gun will come with directions on how to use it's parts.
It's important to get the gun set comfartably for yourself. That will enable you to set your own pace. You will be able to control the paint alot better if you feel comfortable.
Try not to take your hand off the trigger on the gun while you are painting. This will keep your flow consistent, avoiding any mishaps.
Flow is also considered how you lay paint across an object being painted. Consider the frame in your mind. Think about it lines and contours. Now try to paint while following those lines and contours. If that makes no sense, watch the discovery channel's show American Hot Rod or The The learning channel's Overhaul n". They always show some guy painting a car. And they are always doing it this way.
Chromasystem paint is pretty forgiving. I have never created a dribble or a sploch of any sort. While following the rule of flow. And I am just a novice. You can set the spray gun to shoot as much as you want, at any given rate you want to. So ,use it to your advantage.
5. Lay down at least four coats of etching primer.
Allow 15 minutes or so between coats to let the paint breath or (Flash). This lets some of the chemicals in the paint wick away from the paint which is a good thing. It wards away possible air bubbles in the paint. It also keeps the paint coverage under control. If you lay too much wet on wet layers of paint you risk dribbles and sploches. Once the fourth coat is dry you are ready to sand.
6. Use automotive wet/dry sandpaper to wet sand the paint.
You want to use a "fine" grit paper (220 grit paper is good). If you created a dribble use 800 grit paper to level it out.
You want to sand until every part of the frame is smooth and even. Check this with your eyes and hands. Try not to be too grabby with your hands you don't want to get too much grease on the primer coat. A finger just barely touching will tell the truth.
You can add some water to the frame while you sanding. The water will help make the coat smoother.
It doesn' t really take that long to sand belive it or not. And a good sand job will affect the overall look of the paint job. Thats why I say you can use spray paint out of can. Sanding gets rid of the uneveness of poor quality paint.
When your done sanding blow off any loose sanding dust and hose off with water. Run your hand along the frame while you are hosing off the frame, to get off the any caked on dust. Use a rubber glowe when you do this as to not get any grease on the frame from your hands.
7. Mix any color coat paint with it's basemaker.
Remember basemaker is what cures the paint. So, once you have added it to the paint you have begun the curing process. This is something you can consider when purchasing a basemaker. You can control the cure time by using a low temp or high temp basemaker.
Mix what you need at that time so you can conserve on the paint. I have found that I can get at least two coats out of half of the half quart of paint I bought, sometimes more.
Buy a cheap plastic paint measuring pale and some mixing sticks this will help.
Load the spray gun and shoot. Remember to use the same proper flow technique from above.
I only put four coats of color base on the frame, some do more. Check with the paint shop you choose to see if they can give you a idea of how many coats you will need for the given paint you have selected.
8. Again use the same 220 grit automotive wet/dry sandpaper to sand the finish.
This time definitly use the water on the frame while sanding.
This will help remove any "orange peeling" you get when the paint dries. Orange peeling is when the paint starts to look like the surface of an orange peel. You might not be able to see this until the clear coat is on.
The shine of the clear coat will bring out all kinds of imperfections. And you cannot sand clear coat. So, wet sanding is very important at this step.
Once you are done sanding and you've eyed over the smoothness, hose the frame down with water getting all the sanding dust off. Let it dry thourouhly.
Make sure there is no water on or inside the frame at this point. And blow off any remaining dust with the air compressor. If you mess up while putting the clear coat on you might have to start all over again. Plus you will be extremely [censored].
9. This is where you would want to place any decals or stickers on your frame.
Deacals and stickers will lay under the clear coat. You can make stickers at local sign shops. they give a cool raised effect when you use heavy vynil to make them.
10. Mix your clear coat (if it's a two part system).
I use a clear coat by Dupont and it cures real fast so mix enough for two coats and keep all of it in your paint bucket on your gun. Don't over mix because you will have wasted anything that you can't keep in a covered container.
Spray it on, again the same way you layed the base color and primer down. Give 15 to 30 minutes between coats to let it cure (flash). I use two or three coats but it's up to you. let the clear coat cure and see how you feel.
Just remember to be a little more careful with this step because you cannot sand clear coat. So, any problems and your back to square one.
Now let the frame sit for a day to cure. A couple of days might be good. But we all know how that goes.
Note: Clear coats and base colors also come in matte finishes. These will add effect to any paint job.
Finished
That's it! I know it might seem like a lot by all the writing I did. Once you get passed all the writing about the equipment the steps are easy. If you plan properly and use the techniques you can finish it in one day. Probably less if you have a good space to work in. This of course is how I do it. I am sure there is someone who has been doing a lot longer that will probably ream me every which way for sounding like an ass in my descritpions. But it works! and I have had no complaints with the work I've done. When you look at how much money you would spend having someone else do it, why wouldn't you do it yourself. Other than it's too messy. At least this way you wouldn't be confined to a paint shops color chart. Not to mention if you are a techhead this goes great in the arsenel of things you could do. I run into at least one or two people a week who are thinking about painting their bike if I mention I can do it for them. You could charge pretty good prices for doing it to.