Painting plastic material could be one of the most cumbersome tasks, especially when wrong paint selection and improper procedures are undertaken. Usually, the finish paint coat may peel, fade, or flake with time, thus leading to primary material weakening.
Well, in this article we shall have a discussion on how to paint plastic. To begin, you select the tools and material required, clean the surface, strip the old paint and sand gently, polish the surface, and blow off the dust and dislodged debris.
Select appropriate plastic paint, prepare the paint sufficiently (as per the manufacturer’s instructions), apply the paint (1st coat), and then undertake quality finish before leaving the surface to dry to touch.
DetailHow to Paint Plastic (DIYer’s Guide – Pictures)
Priming is not always needed when painting plastic (unless the surface is under paint restoration), while the 2nd paint coat should only be applied to attain a quality finish if necessary.
Tools and Material Required
Importantly, always wear protective gear when painting plastic for your personal safety.
- Plastic paint and a paintbrush
- Fine grit sandpaper and mineral spirit or thinner
- Polishing machine and Paint sprayer (optional)
- Empty buckets (2) and Piece of cloth
- Painter’s tape and primer – if needed
- Soapy detergent and respirator
- Overall and boots
- Blower and Stirrer
- Paint scraper and stripping chemical
- Vacuum cleaner and sander – optional
- Hand gloves and eye protection – goggles
1. Surface Cleaning
- Wear protective attire – gloves, overall, respirator, boots, and goggles – for personal safety
- Sweep the plastic surface (using a broom) to remove dust and debris. Alternatively, vacuum the surface gently
- Using a wet piece of cloth, mop the surface and leave it for some minutes to dry naturally
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2. Paint Stripping and Sanding
The plastic surface that is previously painted requires paint stripping in order to improve paint stickiness level and boost quality finish. However, freshly made plastic material doesn’t need sanding or stripping.
- Pour the stripping chemical into an empty bucket and thin sufficiently – follow the manufacturer’s instructions
- Apply the stripping chemical (using a paintbrush) over the painted plastic material until the entire surface is covered
- Leave the stripping chemical to cure for 10 minutes or otherwise advised by the manufacturer
- Using a paint scraper, scrape off old quenched paint gently – be careful not to damage primary plastic material
- Repeat the previous step once more until the old paint is completely removed
- Using fine-grit sandpaper, sand the plastic surface to remove paint remnant and rough surface scratches that may have occurred
- Blow off dust and mop the surface before going to the next step
3. Polishing and Blowing
- Connect the polishing machine to the power source and switch on
- Gently, run the polishing machine over the sanded plastic surface – back and forth
- Repeat the previous step until you attain a smooth surface finish
- Connect the blower to the power supply and blow off paint debris and polished material – from the surface
- Dip a piece of cloth in soapy detergent and clean the polished surface – to remove paint debris and remnants of stripping chemical
- Rinse the surface with clean water and leave it to dry to touch
See Also: HVLP Paint Sprayer for Latex Paint
4. Paint Selection and Preparation
When selecting plastic paint for your plastic structure, consider factors such as stickiness level, fast-drying, scratch resistance, fade-resistance, and the extent you want to paint.
Consider spray paint than other paint options. However, you can opt to use a paint sprayer in order to attain an excellent finish coat.
Further, plastic surfaces are best coated using oil-based paint than latex paint – offers better surface adhesion.
In case you consider using a primer, match it with preferred finish paint – oil-based finish paint should be used with an oil-based primer and vice versa
- Pour finish paint into an empty bucket gently and thin appropriately – as per the manufacturer’s instruction
- Using a stirrer, stir the solvent until you attain uniform solvent
- Carry out a drop test experiment over the plastic surface – to ascertain the stickiness level
- Alternatively, load the paintbrush and assess the drain capacity – a well-thinned paint should load on a paintbrush without any drains
5. Actual paint Application
- Dip a paintbrush into thinned paint and load sufficiently
- Cut excess paint – prevent runs or surface drains
- Apply the paint (back and forth) over the plastic item gently
- Repeat the previous step until the entire surface is painted
- Leave the surface to dry naturally
- If necessary, add the second paint coat to improve the finish quality
- Then, leave the wet paint to dry to touch
6. Quality Finish Coat
To attain the best finish coat, it’s advisable to seal the finish paint. To achieve this, line the final coat with light paint solvent.
Then, apply the paint sealer until the entire surface is covered. Leave the sealed plastic material to dry naturally.
Always cover the sealed plastic item with a polyethylene bag in case it’s found in a dusty environment – to prevent it from dust stains.
Major Painting Problems Associated with Plastic?
Wrongly painted plastic items experience some of the following problems:
a. Peeling and Flaking
Peeling is a condition where the paint coat detaches from the surface due to low adhesive contact.
Usually, paint peels or flakes due to insufficient surface preparation, wrong paint selection, and inappropriate paint thinning.
Moreover, the paint may peel due to extreme weather conditions such as dusty or intense solar radiations, which weaken the surface adhesive bonds and hence initiate peeling or flaking action.
Always select paint that’s suited for plastic material and avoid insufficient surface preparation in order to prevent paint peeling or flaking.
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b. Fading and Aging
Fading is a situation where the initial paint color loses its intensiveness and impression with time. Paint fading causes outlook deterioration and kills the aesthetic impression.
Major causes of paint fading include poor paint molecular composition (low-quality paint), extreme weather conditions (UV-rays), excess heat contact (near a furnace), exposure to fading chemicals, and dust/surface debris.
Consider paint that integrates UV-ray blockers and resists fading. Moreover, the selected paint should resist aging and extreme solar insolation – for items found in a sunny environment.
c. Runs and Drains
Drains and runs occur on the painted plastic surfaces due to the use of over diluted paint or wrongly thinned paint.
Besides, drains can occur when excess paint is applied and items tilted before drying has occurred.
Runs and surface drain form streaks and surface marks that are cumbersome to remove once dried.
Indeed, drains destroy outlook impression and eliminate finish smoothness, which is one of the marks of quality.
NB: Always clear drains or runs before they are dried and avoid scratching dried runs – may destroy the paint coat.
Chipping is a common problem that occurs on paint plastic surfaces found in humid or wet environments due to point paint weakening.
The chipping process begins when moisture comes into contact with the painted plastic surface (section) – paint adhesive bond is weakened at that particular point and hence begins to chip or disintegrate.
Chipping may also occur when finish paint is exposed to external agents like lime, acid, excess heat, or even UV-rays exposure. Once the paint begins to chip, it’s advisable to repaint or restore the entire surface.
Maintenance Tips for Painted Plastics
In order to enjoy the improved surface life of your painted plastic items, consider putting into practice some of these maintenance tips:
- Avoid leaving painted plastic items over the direct sun for a very long time
- Dust your painted plastic regularly – dust weakens paint and initiates peeling or chipping
- Never paint over a painted chair (old paint) – paint stripping is required to improve surface stickiness
- Paint your plastic items often – after every 2 or 3 years – in order to maintain an initial outlook impression
- All old plastic item should be taken to a recycling plant instead of throwing them into a dustbin – most plastic items are not biodegradable and hence end up causing environmental pollution
- Industrial Chemical should be eliminated from the painted plastic surface – may react with surface material upon contact
- Always keep your painted plastic item dry to touch (free from moisture) in order to eliminate chances of chipping or scuffing from occurring.
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Precautions to Consider when Painting Plastic
When painting your plastic item, stick to safety measures and precautions highlighted below:
- Always follow manufacturer’s instructions when preparing plastic primer and finish paint
- When sanding and polishing plastic surfaces, be careful not to damage the primary surface material
- Before you begin surface preparation, wear appropriate protective gear – for safety purposes
- Carry out a drop test experiment before actual paint application is carried out – to assess surface stickiness level
- Never inhale thinner, primer, or finish paint – this solvent may contain components that might irritate your nasal cavity when inhaled
- In case you get into contact with thinner or finish paint, clean the section with water and soap
- Cover your painted plastic items if located in the dusty environment – to prevent them from dust stain
- If possible, use a paint sprayer when painting your plastic items in order to attain strong paint adhesion. Alternatively, you can go for spray paint.
You can always omit to prime your plastic structure (unless the surface is under paint restoration), while the 2nd paint coat should only be applied to boost overall quality finish where necessary.
For safety purposes, always wear protective gear when painting plastic and stick to precautions highlighted in this article.
See Also: Using An HVLP Paint Sprayer
On how to paint plastic, you begin by selecting the tools and materials required, then clean the surface, strip old paint and sand gently, polish the surface, and blow off the dust and dislodged debris.
Choose appropriate plastic paint and prepare it sufficiently (follow the manufacturer’s instructions), carry out actual paint application (1st coat), and then line the finish coat before leaving the surface to dry to touch naturally.
Cover painted plastic surface found in the dusty environment to prevent it from dust staining.