Powder coating is the process of coating metal with a plastic in the form of a powder brought to a liquid state to bond to the metal surface. Powder coating has several advantages over traditional liquid paint: it pollutes less, it is applied in thicker layers without the need to spread and it is easy to style it. While some aspects of powder coating can be intricate, it certainly isn't difficult, especially for an enterprising soul. A good cleaning and the right tools can make the difference between a good job and one done as a beginner.
Steps
Method 1 of 2: Apply the Powder Coating
Step 1. Determine the type of material you are going to paint and then choose a suitable powder
The powder coating is done with thermosetting or thermoplastic polymer powder, materials that are designed to bond to different types of metals for best results.
Read the next section for a broader discussion of the differences between thermoplastic and thermoset coatings. What is good for a car may not be good for small accessories or decorations
Step 2. Disassemble all threaded or lubricated parts before starting, including anything you don't want to paint
It sounds easy but many forget this step. The powder coating will stick to anything (if done right) making all welded parts, bearings, clamps, bolts, nuts and so on useless after blasting.
Step 3. Clean the metal thoroughly
Using sandpaper or other abrasive materials on metal, such as cast iron or steel will remove rust, dirt, and other debris. The chemical solvents will eliminate traces of grease, oil or paint, passing a little fine sandpaper will clean the surface and prepare it. Aluminum, magnesium and other light alloys can be cleaned with sandpaper, chemical solvents, and more.
- For example, you could use a sandblaster to clean a surface to be powder coated until the metal is bare. This is the first stage of the process. If you don't have a sandblaster you can always use sandpaper, a spoked wheel or a grinder as long as only the metal remains.
- The next step is to clean the metal of any remaining dirt. You can soak it in acetone (if the object is small enough) or wipe it with a rag soaked in acetone.
Step 4. Apply the powder to the object to be painted
You can use a "pistol" or a compressed air sprayer which will electrostatic charge the powder thus making it stick to the metal that will be painted. These guns can be found in normal shops and cost less than € 100. For experimental purposes, you can apply the powder by dusting it directly onto a flat metal surface and spreading it with a thin, even layer.
- Make sure the surface to be treated has an electrostatic charge or the dust you use will not stick properly.
- After putting the cover on but before it solidifies, be careful not to sweep or blow on the dust otherwise you will drop some of it with the result of having a less precise cover.
Step 5. Allow the metal to dry at the temperature suitable for the powder you are using
A normal oven is fine if the object is small enough, otherwise an infrared lamp or other flameless heat source may be fine. Usually the temperature used is between 175 ° and 190 ° C for 10 to 15 minutes, then let it cool down.
You can use a regular oven for smaller items. Just make sure you don't cook in the oven you used with the powder paint. Once used with paint absolutely must not be used for cooking.
Method 2 of 2: Thermoset vs Thermoplastic
Step 1. Use a thermoplastic cover on objects that you could possibly remodel, and thermoset covers for objects that essentially will stay that way
The main difference between thermoplastic and thermoset is the reversibility of the covering. As the name says in part, thermosetting covers are irreversible processes due to the chemical reactions that take place. On the contrary, thermoplastics can be remodeled precisely because certain chemical processes do not take place.
Thermoset covers are good for electronic products or appliances because they have to withstand high temperatures that could cause the thermoplastic covers to melt
Step 2. Choose according to the characteristics
Thermosets and thermoplastics have different chemical properties that make them ideal for different uses. Knowing some of these properties will help you choose:
- Thermosetting they strengthen the structural integrity of an object making it particularly suitable for severe wear. They also provide the object with superior chemical and heat resistance as mentioned above.
- Thermoplastics offer a mix of strength and flexibility. Used for common items such as plastic bags and mechanical parts.
Step 3. Learn the advantages and disadvantages of thermosets
They are often used for household appliances because they can withstand heat.
- Advantages: excellent aesthetic appearance; economic; they add strength and stability; resistant to extreme temperatures.
- Disadvantages: being an irreversible process they cannot be recycled; more difficult to finish; they cannot be remodeled.
Step 4. Learn the advantages and disadvantages of thermoplastics
They are used for various objects, such as benches that need plasticity and durability.
- Advantages: high lubricity or adhesion; recyclable; they can be remodeled and / or redefined; higher impact resistance.
- Disadvantages: (usually) more expensive; they can melt if overheated.
Advice
- Thoroughly clean and rinse all metal surfaces, as well as all paint covers.
- Powder paint is a type of finish that does not harm the environment, resistant to corrosion and ultraviolet light. While it is best applied with precision industrial equipment, it can also be placed indoors.
- Stay in a clean, well-ventilated area.
- There are several tools for doing powder coating, such as guns, which are found online.
- Preheat each part to be treated beforehand before covering it. This will eliminate any traces of grease or oil left on the surface. If the part is not preheated, oil and grease will remain on the surface releasing gas and forming bubbles on the finish as it hardens.
- Remember that you will have to heat the treated piece in an oven to fix the cover, so you will have to have an oven large enough to hold the object, or have a heat source such as an infrared lamp to hold the object for long enough.
- Collect all excess dust for future reuse.
Warnings
- Do not use a gas oven.
- Do not touch the object removed from the oven after drying until it has cooled down.
- It is not recommended to heat the cover in an oven used for cooking.
- Do not breathe the powder when you apply it.
- Use respirator, gloves, and goggles when using abrasives to clean metal.
- Do not swallow!
