First paint job
by: Biker chic, Chris66dad, Cobalt327, Crashfarmer, Crashtech, Crosley, Deadbodyman, Hammerheadkustoms, JerryMopar, Jon, Lbell101, Powerrodsmike, Schnitz, Techinspector1
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 Cheapo paint job
Paint is expensive, and learning how to paint your car takes practice, patience, and several screw-ups before you get it right.
Faced with the financial obstacle and the learning curve, many hotrodders are tempted to opt for a "cheapo" paint job. The two biggest temptations in the "cheapo paint job" realm seem to be an inexpensive (and questionably professional) paint shop (ie: Maaco), or a cheaper, easier, and ostensibly more forgiving product line (ie: DupliColor).
If you've put any amount of effort or money into building the mechanical aspects of your hot rod, you will most likely want to complete the project with a proper paint job. "Cheapo" solutions work fine for beaters and work trucks, but they aren't appropriate for non-Cheapo vehicles.
As with most other aspects of constructing your car, when it comes to paint, you get what you pay for. Cheapo paint shops do low-quality work. Cheapo, "easy-to-use" products will never provide a quality, long-lasting finish of which you can be proud.
Nevertheless, many newcomers are still tempted to opt for the cheapo route, a path against which body shop professionals frequently advise.
For a full explanation of why, in most cases, a cheapo paint job is a bad idea (and, suggestions for when it's not a bad idea), see Cheapo paint job.
 General tips, tricks, and techniques
- A 12" aluminum ruler works great for ratios example: 4:1:1 = 4" :1" :1". Stir your paint with it and wipe it off so you can reuse it later, you can find them everywhere for $1.
- Save your old reducer gallon cans and quart size hardener cans. With a pair of tin snips, cut the tops off (at the bead), and use them for mixing paint with a ruler -- but run some tape around the edge so you don't cut yourself.
- When opening a can of paint, punch a few holes in the trough where the lid sits with a hammer and nail. That way, excess paint will drain out of the trough and into the can, rather than splattering when placing the lid back on the can.
- Buy a set of inexpensive spatulas to use as scrapers for paint cans.
- To preserve hardener, displace the air in the can with inert gas, such as the shield gas (CO2/argon, etc.) from a MIG welder. Or, use a commercial inert gas finish preservative such as Bloxygen.
- For easier pouring, affix a 2-inch piece of masking tape to the edge of a large gallon of paint. Pour the paint over the piece of tape.
- Use a ladle for handling paint.
- When purchasing new paint or other finishing products, write the date on them with a black magic marker.
- For stirring paint, use inexpensive "jumbo sticks", tongue depressors, Popsicle sticks, wood sticks, or butter knives.
- Paint stirring sticks with marks for different mix ratios can be useful for mixing paint.
- When opening a gallon of paint that isn't all going to be used immediately, mix it very well and pour it off into quart cans. You can get empty quart cans from a local (private, not chain-store) paint shop for cheap or free. While pouring, intermix the paint; pour a little bit into each can at a time.
- Leftover paint with hardener can be placed in the refrigerator. The cold temperature will slow down the hardener. You can even throw you spray gun in there if you find you need some supplies, and you are in the middle of painting.
- It pays to completely blow off the whole car inside and out with compressed air before you begin painting. Wear eye protection and a respirator.
Warm and dry conditions are ideal for spray painting. The ambient temperature range for spraying most modern paints is about 65-90 degrees Fahrenheit. Be sure to choose the hardeners and reducers for the temperature range you'll be working in. Aerosols don't always work best in the damp and colder temperatures, which can hinder drying time, although it can be done. If it's not warm and dry outside, work in a well-ventilated garage, but set it up for painting.
Try to keep your gun straight, not angled to far up or too far down. Keep the gun about 5 to 6 inches from the surface the whole time, or you will have heavy painted surfaces and lightly painted surfaces. Practice spray technique on an old fender to determine proper gun adjustment, pass speed, and pass overlap.
 Building a temporary paint booth
See: Building a paint booth.
Painting in a garage lessens the chance of bugs or dust ending up lodged in your paint while it is still in its curing stage. One way to turn your garage into a temporary paint booth is to buy large plastic drop cloths from you local hardware or home improvement store. They are a cheap and effective way to protect your tool boxes and "toys" from overspray.
A good rule of thumb for blower sizing is to try to change the air TWICE every minute. Hence, if you have a 10'x10'x10' paint booth (1000 cubic feet) you want a 2000 cfm blower (2000 cubic feet per minute). Open up your garage door about 1/8 to 1/4 up. This will help with ventilation, since solvents sink to the floor. Place a fan near the opening, facing outside, to help even more with airflow. Opening any side doors and roof vents and placing additional fans will help ventilation. Box fans may work, but at a minimum you should ensure that these fans are the brushless type to reduce the amount of sparking the exhaust stream will be exposed to to lessen the chance of an ignition. Remember, the fewer sparks the paint vapor "sees" the less likely you are to cause an explosion.
An even better solution to box fans would be to use squirrel cage blowers, commonly found in HVAC and exhaust vent systems. Try to get the type where the motor is outside of the squirrel cage to reduce heating the exhaust stream. Place the squirrel cage blower motor outside of your "paint booth" and run ducting into (or out of) your paint booth.
Something that will help keep dust and bugs from coming into your garage is to buy a furnace filter the same size as the window (or build a frame for the filters to go over your door) that you have open. This will collect the dirt and bugs before they become part of your paint job. If there are strict rules in your area, something that will help is to place a filter before your fan so that it filters the air as it is leaving your shop.
 Basic mixing techniques
Paint and related finishing products can be mixed in glass measuring cups, medicine cups, soup cans, or shot glasses. However, E-Z Mix cups are generally preferred for ease of use. Containers with measurements marked on the side are generally most useful. Paper cups are cautioned against because some may have a wax coating. Similarly, plastic cups or containers (medicine cups, yogurt containers, cleaned bottle caps, etc.) are also cautioned against. There are many different kinds of plastic, some of which are inappropriate for storing certain types of finishing products.
When mixing double portions of paint or primer, mix one portion at a time. For example, 8:2:1 easier to keep track of than 16:4:2. Most, if not all, automotive paint has the correct ratio for the paint/thinner/hardener printed on the label. If not, consult your favorite painter or paint store counter person for the correct ratio to use on your paint.
After mixing each individual portion, add the two portions together and mix well again. This also cuts down on wasted material if you make a mistake (too much hardener, wrong reducer, etc.).
 Proper paint clothing
When painting, it is always a good idea to wear some kind of protective clothing. It not only helps keep you from contacting the toxic materials but it also will help keep unwanted materials from getting on your paint job. The first and most important is a respirator made for automotive refinishing. There are a lot of companies that sell these. Get a paint suit or use a lint free pair of coveralls. Tyvek suits are available at many hardware stores for around $10.
The next thing is a pair of gloves. Nitrile gloves hold up well to chemicals (see: Hand cleaner). Additionally, nitrile gloves will block the toxic isocyanates found in the activators of many 2k paints; latex will not block these chemicals. Do not use a set of rubber gloves as they are too clumsy and you need the motion that you get from the latex style gloves.
 Head cover
Get some kind of lint free head cover, this keeps your hair on your head and not on the job you are working on. You can also use a foot cover, which looks like a sock for your shoes.
 Paint mask
The most important item that you need is a paint mask. You can get by with out the other items (with extra buffing when you are done) but the paint mask is the most important.
Before entering the area that you are refinishing your project in take a air nozzle and blow yourself off. This will get rid of any extra surprises that will fall into your job
 Health and Safety
Painting materials can do major harm to your health if you do not closely follow the manufacturers recommendations for skin and lung protection.
Auto paints can contain many dangerous chemicals. It is important to protect yourself properly.
A respirator or fresh air system should be worn at all times when you are working with paints. Even when mixing your paint and getting ready.
 Spray gun tech
With a spray gun, you get what you pay for!
HVLP (High Volume Low Pressure) is the way to go when buying a spray gun although LVLP (Low Volume Low Pressure) can work acceptably with the right paint. The prices have come down to reasonable levels, and the wasted paint by overspray (not to mention the mess) makes a siphon-feed unit a poor choice for the home hobby sprayer.
Remember that high-solid primers like high-build type 2K urethanes require a larger (1.7mm) tip and setup internally than a regular paint gun. Three gun sets are available for as little as $100 that include a primer gun with the larger tip, a paint/clear gun, and a 1.0mm tipped touch-up gun. Cutting (wet sanding) and buffing make up for a lot of shortcomings in inexpensive HVLP guns. So determining which is more valuable, your money or your time, is a determining factor in choosing a paint gun. A cheaper gun will require more time spent cutting and buffing than a top-of-the-line gun that lays paint out more evenly, but at an added price of several hundred dollars. A budget gun can be had for under $30, whereas a SATA 3000 digital runs around $650. You decide which is more important.
 Choosing the right type of paint
If unsure, you can ask other car builders that have done their own paint work, or if you know a painter, ask them. Best of all is to consult with the paint salesperson when you go to buy paint. They are a wealth of information. Utilize them. That's what they are there for.
 Single stage:
One stage, no clear coat. For people looking for a budget paint job. Not as glossy or durable as a 2 stage, although it easily oxidize or fade, it can easily be buffed out.
- Synthetic enamel: dries naturally and leaves a glossy finish. Two parts- paint and reducer.
- Acrylic enamel: just like synthetic, but with a hardener or catalyst. Cures within hours and a little more durable than synthetic enamel.
- Acrylic urethane: the most durable single stage paint. It has more UV and chip resistant over the enamel paint.
 Two stage:
- Base coat/clear coat :modern paint,the most durable of all. Gives the best gloss and longevity. But once the clear coat is gone you will need new paint job.
 Three stage:
Base coat, then pearl or metallic, then a clear coat.
 Two main types of all automotive paint colors
 Solid paint
Solid colors are a little easier than metallic to paint. If you mess up and get a run in them, they can be fixed rather easily by color sanding and buffing.
 Metallic paint
Spraying metallic is a little different then spraying a solid color; they can easily mottle (have blotches of dark and light areas) and/or "tiger stripe" if sprayed incorrectly. The key to spraying metallic paint is to move the "dry spot" around. For example, spray one coat one direction, then the next coat in the direction 90 degrees to the first coat. Overlapping the coats up to 75% is another key to good metallic finishes.
Remember, anytime that the paint moves the metallic does as well, so if they run you will get the metallic all in one spot. With metallic, always use the suggested reducers and mix the entire batch to be sprayed at the same time. DO NOT play mad scientist/chemist. Follow the instructions to the letter. The engineers at the paint companies spend millions on R&D, so they are already sure of the results you will get by mixing the product any given way. Do not re-invent the wheel.
- Always follow the manufacturers' recommendations for every product that you use. This usually means thoroughly reading the associated tech sheets, which are typically available for download from the manufacturer's website. For further detail, see Rules, Rules, Rules, an editorial post by MARTINSR on the Hotrodders Bulletin Board.
- Never soda blast unless you know how to completely remove the residue, and fully understand the complexities associated with soda blasting. See: Soda blasting.
- Autobody101.com forums
- Autobodyonline.com forums
- Autobodystore forums
- Hotrodders.com body and exterior forum
- SPI Users forum
- http://spi.forumup.org/about2379-0-asc-0-spi.html (lots of tips here, needs to be incorporated into article)