How to Protect Paint and your machine from Contamination On-Site

When you’re working on a busy site or an industrial setting, your paint is constantly at risk. Dust, dirt, rubble, and airborne debris are everywhere. Add in the chaos of trades moving around on site, vehicles driving past, and doors/windows left open, and it’s no surprise that open paint tins become contamination magnets.

But contaminated paint isn’t just an inconvenience it can seriously damage your spray equipment, ruin your finish, and waste valuable time on site. Protecting your paint is one of the simplest and most important steps you can take to ensure optimum productivity and profitability.

No matter the kind of site or industrial environment, paint contamination risks are everywhere.

Let’s look at potential problems it can cause, and how to prevent it.

Paint Contaminate On-Site:

On a live site, anything airborne or loose on the floor is a potential contaminant. Common culprits include:

1. Dust and Powder

Building sites are dusty by nature: plaster dust, sawdust, cement powder, sanding residue. These particles easily drift into open tins or buckets.

2. Dirt and Rubble

Foot traffic and moving equipment kick up dirt, gravel, brick fragments, and grit. Even small particles can cause major issues in spray machines.

3. Rust, Metal Shavings, and Paint Flakes

Renovation sites may have peeling surfaces, grinder residue, or corroded materials.

4. Organic Debris

Leaves, insects, fibres, plastic scraps, anything light enough to fall into an uncovered container.

5. Water Contamination

Rain, condensation, or accidental splashes can dilute or chemically interfere with coatings.

For more about protecting paint against extreme temperatures, read at our blog about storing paint correctly.

Why Contaminated Paint is a Big Problem for Paint Spray Machines:

Graco spray machines are designed for high performance, but they rely on clean, consistent paint. Even tiny foreign objects can create serious faults.

1. Loss of Prime

Contaminants can block filters, valves, or passages inside the pump, causing it to:

• lose prime
• stop pumping
• surge or pulse

Once this happens, you may need to flush the system or even strip it down completely.

2. Pump Damage

Grit or hard particles can:

• score the pump rod
• damage packings
• wear out the pump cylinder
• create internal leaks

This shortens machine life and leads to costly repairs.

3. Blocked Tips and Gun Filters

Anything bigger than a grain of sand can:

• clog your spray tip
• restrict flow
• cause spits and uneven spray patterns

Blocked tips are one of the most common symptoms of dirty paint.

4. Increased Maintenance Time

When paint is contaminated, you often have to:

• remove paint and debris from the hopper/bucket
• clean strainers
• flush the machine repeatedly
• remove lines, guns, and filters for cleaning

All preventable by simply covering the paint.

How Contaminated Paint Ruins your Final Finish:

Even if your machine survives, your finish may not.

1. Grit in the Paint Film

Particles leave:

• speckles
• bumps
• rough texture
• drag lines when rolling back

This is especially noticeable on walls in good lighting or on trim finishes.

2. Inconsistent Spray Pattern

Contamination can affect atomisation, causing:

• tails (thick edges)
• spitting
• patchiness
• banding

3. Colour and Sheen Issues

Water or chemical contamination can:

• alter colour
• flatten sheen
• cause patchiness after drying

4. Rework and Wasted Product

If contamination affects the finish, you may need to:

• sand back
• respray or repaint
• buy more paint

How to Protect Paint From Contamination On-Site:

You only need simple, inexpensive habits and tools.

1. Cover Your Paint

No exceptions. Any time you’re not actively pouring or spraying, keep it covered.

What can you use to cover paint?

• Lids (if you can this is the best option)
• Plastic sheeting secured with tape
• Stretch wrap / cling film
• Bucket lids
• Purpose-made elastic paint bucket covers
• A piece of card or board as a temporary barrier

2. Check Your Environment Before Setting Up

Ask yourself:

• Am I near a dusty cut station?
• Are trades kicking up debris close by?
• Is the ground covered in dirt or rubble?
• Are vehicles driving past?
• Is wind blowing through open doors or windows?

If yes, move your setup to a cleaner zone or protect it accordingly.

3. Strain Your Paint

Use a paint strainer before filling your hopper or suction tube. This will catch:

• dust
• grit
• dried skin from old paint
• flakes

It’s cheap insurance.

4. Keep Your Equipment Off the Ground

Place buckets, lids, guns, nozzles on a clean surface, not directly on the dusty floor.

5. Practice Good On-Site Paint Hygiene

• Seal tins during breaks.
• Don’t leave paint in high-traffic areas.
• Keep water buckets covered.
• Clean the rim of tins to ensure lids seal properly.

Good habits ensure clean paint, a productive sprayer and a high-quality finish.

Protect your Paint, Protect your Machine, Protect your Finish.

Contamination is one of the most common causes of:

• machine faults
• lost prime
• blocked tips
• damaged pumps
• poor finishes

And nearly all of it is preventable.

A simple habit like covering your paint can save hours of downtime and hundreds of pounds in repairs. If you do require service and maintenance of your machines, get in touch with the Spray Plant UK team.