A paint spray in a RAL colour is the tool of choice in workshops, industry and trade whenever components, housings, railings or machine parts need a defined shade or require touching up. The advantage over a mixed colour lies in its reliability: a RAL shade is unambiguously defined and can be reordered at any time. For the result on the component to match the intended shade, however, substrate, primer, paint and clear coat must all work together. This guide shows what matters when selecting and applying the product.

What a RAL shade means for a paint spray

The RAL colour system assigns a four-digit number to every shade. The first digit indicates the colour group: 1000 series shades are yellows and beiges, 2000 series oranges, 3000 series reds, 5000 series blues, 6000 series greens, 7000 series greys and 9000 series whites and blacks. Anyone painting a component in RAL 7035 light grey obtains the same shade that a control cabinet manufacturer or a metal fabricator uses under this number.

Three points matter in practice:

The RAL number describes only the shade, not the gloss level. Whether a surface appears matt, satin or gloss is determined by the paint formulation.
The colour impression depends on the substrate. A light RAL shade on a dark substrate needs more coats or a light primer to reach the target shade.
The binding reference is a comparison with a RAL colour sample in daylight, not the rendering on a screen.

The Aerosols Germany range includes, for example, paint spray RAL 1013, paint spray RAL 1015, paint spray RAL 2011 municipal orange, paint spray RAL 3000, paint spray RAL 6018, paint spray RAL 7032 and paint spray RAL 7035 as acrylic-based universal paints. Further shades are available on request.

Selecting the right shade

Touching up existing parts

For touch-ups, the original colour sets the shade. If the RAL shade is known, for instance from the drawing, the type plate or the manufacturer's specification, exactly this shade is ordered. If it is unknown, a RAL fan deck helps: the sample is held directly against a clean area that is as unweathered as possible. Bear in mind that older paintwork can fade through UV light and weathering. The repainted area will then look fresher than its surroundings even though the shade is correct.

Coating new parts

For new parts, the shade can be chosen freely. In industry, typical shades have become established for certain applications, such as greys for control cabinets and machine frames, signal colours for barriers and hazard points, or municipal orange for vehicles and equipment in the public sector. Anyone coating visible parts in several batches should document the shade including the gloss level so that later deliveries match existing stock.

Primer and adhesion primer: the basis for adhesion and coverage

A top coat adheres only as well as the layer beneath it. The primer has two tasks: it bonds the substrate to the top coat and creates an even, absorbent surface on which the shade builds up homogeneously.

Substrate	Preparation	Recommended primer
Bare metal, steel	Degrease, remove rust, sand	Primer grey or primer red-brown
Rusted metal	Remove loose rust, degrease	Rust-Stop long-term primer red-brown
Plastic	Clean, degrease, lightly roughen	Plastic primer
Wood	Sand, remove dust	Primer, several coats on absorbent woods
Old, intact paintwork	Clean, sand, degrease	Primer only if the old coating is uncertain

The primer grey from the range is intended for plastic and acrylic paints and, according to the product description, improves both adhesion and corrosion protection. For plastic parts, the plastic primer is the right choice because it adheres to common plastics and fills small scratches and grooves.

Coverage: how to build up the shade evenly

Coverage describes the ability of a paint to hide the substrate completely at a given film thickness. Light and pure shades such as yellow, orange or red generally cover less well than grey, black or dark blue because their pigments absorb less light. For these shades, the following applies:

Choose a light primer. A grey or white primer reduces the number of top coats required.
Apply several thin coats rather than one thick coat. Thin coats dry evenly and do not form runs.
Observe the flash-off time between coats as stated on the label.
Spray in a criss-cross pattern: first horizontally, then vertically. This prevents streaks.
Shake the can before every use for as long as the label specifies so that pigments and binders are evenly distributed.

The spraying distance and the working temperature are also stated on the label. Too short a distance leads to runs, too great a distance to a rough, matt surface because the paint starts to dry in the air.

Clear coat for protection and gloss

A clear coat is not mandatory with universal paints, but it offers advantages in three situations: with metallic and effect paints, which look dull without a top layer; on surfaces subject to high mechanical stress; and on outdoor parts exposed to UV radiation. The acrylic-based clear coat spray from the range is intended as a top coat for common paints, is lightfast and abrasion-resistant and protects the colour layer from fading. The clear coat is applied only once the colour coat is recoatable according to the label. Check on a concealed area whether the clear coat is compatible with the colour coat, especially on paintwork from other suppliers.

Substrates in detail

Metal

Steel and aluminium must be free of grease, scale, rust and loose old coatings. After degreasing, the surface must no longer be touched with bare hands. Where rust is present, a rust-converting primer is advisable. On galvanised parts, a suitable primer is particularly important because acrylic paints adhere less well to a smooth zinc surface without an intermediate layer.

Plastic

Plastics vary in how well they can be painted. Hard, polar plastics such as ABS or PC accept paint well, while polyolefins such as PE and PP can hardly be painted without a special primer. Use the plastic primer and, for permanently flexible results, a plastic paint that does not crack under slight deformation.

Wood

Wood is absorbent and releases moisture. It is sanded, dusted off and primed until the surface is evenly saturated. Resinous woods can discolour the paint; an isolating primer helps here.

Typical mistakes and how to avoid them

Not degreased. Fingerprints and release agent residues cause craters and flaking. Always clean with a degreaser before painting.
Wrong primer. A metal primer will not hold on plastic. Choose a primer to suit the substrate.
Applied too thickly. Runs, sags and long drying times. Spray several thin coats.
Flash-off time not observed. The next coat softens the one beneath it and wrinkling occurs. Wait for the times stated on the label.
Working too cold or too humid. The paint dries milky or matt. Observe the working temperature on the label and avoid draughts.
Shade judged on a screen. Only a RAL sample in daylight is binding.
Can not shaken enough. Shade and coverage vary within one surface.

Paint spray in RAL colours for industry, trade and own brands

Aerosols Germany supplies paint sprays in RAL colours, primer and clear coat, produced in Europe and quality-checked in Iserlohn. In addition to the standard shades in the range, further RAL shades, gloss levels and can sizes are possible, including under your own label. Tell us the shade, substrate and area of use and you will receive a suitable quotation.

Are you planning a paint spray programme in RAL colours for your range or looking for a specific shade for series touch-up work? Then send your enquiry to Aerosols Germany and we will advise you on shade, primer and filling.

Choosing a paint spray in a RAL colour and applying it correctly