Covering an object with polyester

Covering an object with polyester has a number of important advantages: the object is strengthened, becomes water-resistant and is easy to colorize. Coating with polyester is therefore often applied to various products. This includes:

• Coating the inside of a van to ensure it meets HACCP standards.
• Covering a wooden object or structure so that it can be left outside for a long time.
• Covering works of art such as statues so that they are strong enough to be placed outside.
• Making custom parts of cars (adjusting bumpers, making custom interiors).
• Covering carnival floats, on chicken wire, wood, foam, etc.
• Covering ponds, swimming pools and roofs.

The methods of the above jobs are very similar, but we have created separate information articles about some topics. In this article we will discuss in general how to cover with polyester using a step-by-step plan.

We have also summarized the steps below in a video.

Step 1. Preparation 

Before you start, it is important that you determine which materials you need and/or whether or not an adhesive primer should be used. For Styrofoam coverings you need a special polyester resin. In the table below you can see what preparation you need for each surface.

Raw materials

• Adhesion primer (if necessary)
• Polyester resin (2 times the total weight of the fibreglass mat)
• Fibreglass chopped strand mat (300 gr/m² or 450 gr/m²)
• Acetone

We also have complete laminating sets for the polyester resin, fibreglass mat and hardener.

Tools:

• MEKP dispenser
• De-aeration roller
• Corner roller
• Nylon rollers
• Velour rollers
• Mixing spatulas 
• Flat brushes (40 mm)
• Small bucket (for the acetone)
• Mixing cups 

Personal protection:

• Vapor mask
• Latex gloves
• Disposable overall
• Or a complete safety pack

Step 2. Applying the adhesion primer

In step 1 you read that in certain cases (wood, concrete and stone) you must pre-treat the surface with an adhesion primer. The consumption of G4 adhesion primer is 200-300 grams per m2, depending on the surface. Apply the 1-component primer with a velor roller or brush. After approx. 1 to 2 hours the primer is dry and it can be coated with polyester. The polyester must be applied within 12 hours of applying the primer. So only apply primer if you continue with the polyester the same day.

Step 3. Applying the fibreglass with polyester

Pour the required amount of polyester laminating resin into a mixing cup and add 2% polyester hardener. Mix this together well. Then apply the resin to the surface with a fleece roller (nylon roller). This way, the glass mats that you are now going to apply will stay in place better.

Tear the fibreglass choppend strand into pieces and place them in the resin. Then apply a layer of polyester resin over this with a nylon roller. For more difficult areas, such as corners, you can use a brush. The fiberglass mat must be wetted in its entirety. White spots have too little resin and shiny spots have too much resin.

Once an entire layer has been applied, you can deaerate the layer with a de-aeration roller. Gently roll over the surface with the de-aeration roller so that air bubbles are pushed out from under the laminate. This is an important part of the process.

Once you have properly vented the laminate, you can apply a second layer. Usually 2 layers of coatings are sufficient to completely cover the surface. With 2 layers of 225 gr/m² you have a thickness of approximately 1 mm. With a heavier glass mat, for example 300 gr/m² or 450 gr/m², the surface becomes more stiff.

Step 4. Finish with polyester topcoat

Polyester topcoat, also known as polyester varnish, provides a finish with a light roller structure. Once the polyester resin has hardened, coarsely sand the surface with 60 grit. This will remove raised fibers and small irregularities.

Pour the required amount of topcoat into a mixing cup. Do you work alone? Then do not create more than what you can process in 15 minutes. Now add 2% polyester hardener to the top coat. Mix both components well and pour the mixture into a paint container.You can easily apply the polyester topcoat with a fleece roller. Apply approximately 300-400 grams of topcoat per m2.

In the video below, Kees explains how to finish polyester laminate with polyester topcoat.

Step 5. Smooth finish with DD Paint

Do you want a smooth high-gloss finish of the polyester layer? First sand it until a flat surface is achieved. Then prepare a generous amount of polyester putty and spread it over the polyester. When the filler has hardened, you can sand the whole thing again. Repeat this process until the surface is completely flat and smooth again.

Then apply a layer of Double Coat DD Paint.

More information?

Do you still have questions or need advice after reading this article? Please feel free to contact our customer service team!