Overview
Alkyd coatings are the oldest and still one of the most widely used paint chemistries in the world. They dry by oxidation — the unsaturated oil or fatty acid in the binder reacts with oxygen from the air to form a tough film.
That simple mechanism is also the source of the alkyd's strengths and its limits. Alkyds are easy to brush, roller or spray, they adhere well to properly prepared steel and wood, they level beautifully, and they are inexpensive. Against that, they cure slowly, they need clean air to dry properly, they have limited chemical resistance and they are not suitable for immersion.
Delshine supplies the complete alkyd range — interior and exterior enamels in the standard colour groups, ready-mixed paints, aluminium and graphite finishes for industrial work, red lead and surface-tolerant antirust primers, and ultra fast-dry grades for maintenance painting where a tank must be back in service the same day.
Ultra Fast-Dry Alkyd Antirust Primer: Iron red grey
Product identification
The identifiers below are the ones printed on the drum and quoted on the purchase order. Always order and dispatch by code, because the grade and the zinc or temperature variant cannot be inferred from the trade name alone.
| Product code | RPAH-402 |
|---|---|
| Trade name | Ultra Fast-Dry Alkyd Antirust Primer |
| Category | Alkyd coatings |
| System role | Primer - first coat on the prepared substrate |
| Manufacturer description | Iron red grey |
Where this product is used
- Interior and exterior enamels for steel and wood
- Structural steel maintenance painting in mild environments
- Ship holds, interiors and non-critical areas
- Agricultural and light industrial equipment
- Pipework and process equipment in dry service
- Metal windows, doors, gates and railings
- Plant maintenance where fast recoat is important
- Protective primer systems for general fabrication steel
How it works in the coating system
A primer is the first layer in the coating system, and it decides how well everything that follows will adhere. Its job is to wet out the prepared substrate, key into its surface, and hold the coating together as one film.
Applied thin, a primer wets and anchors. Applied too thick, it becomes brittle, stresses the substrate and can peel as a sheet. The right dry film thickness for a primer is the one that covers the surface completely without building a film that can crack.
Purpose in the system: Applied directly to the prepared substrate, before any intermediate coat or topcoat.
Technical properties
The values below are the typical published range for this product family. The exact figures for your batch are confirmed on the batch certificate and the current technical data sheet.
| Role in the coating system | Alkyd enamel, ready-mixed paint or aluminium / antirust primer |
|---|---|
| Volume solids | 35–60 % |
| Mixing ratio by volume | Single component; stir and thin with the correct reducer |
| Typical dry film thickness | 25–50 µm per coat |
| Theoretical coverage | 10–16 m²/litre per coat |
| Application methods | Brush · roller · conventional spray |
| Application temperature window | 5–40 °C, minimum 3 °C above dew point |
| Suitable substrates | Prepared steel, wood, masonry and previously painted surfaces |
| Finish / appearance | Full RAL colour range; gloss, satin, matt; aluminium silver |
| Principal resistance | General atmospheric protection, corrosion with the antirust grades |
| UV resistance | Good for the exterior enamels; not for immersed service |
| Adhesion to prepared steel | > 2 MPa pull-off on prepared steel |
| Salt spray performance | > 500 h for the antirust grades |
| Chemical resistance | Limited — oils and solvents will soften the film |
| Abrasion resistance | Moderate |
| Flash point | 20–38 °C |
| Shelf life | 12–24 months unopened |
| Density | 0.95–1.45 g/cm³ |
| Pack sizes | 1 kg–20 kg kits; 200 kg drums |
Surface preparation
- Remove all rust, scale, mill scale and old coating. Alkyd will not perform over active rust — this is the single most common cause of failure.
- Prepare steel by mechanical means to at least St 3, or blast to Sa 2½ for the best result.
- Clean all surfaces with solvent degreasing and remove oil, grease and contaminants thoroughly.
- Round edges to at least 2 mm radius and grind welds smooth.
- Ensure good ventilation during application — alkyd dries by oxidation and needs clean air with reasonable movement.
- Avoid painting in damp, cold or enclosed conditions. Alkyd cure needs temperature and fresh air; it will not dry properly in a sealed container.
Application procedure
Apply by brush, roller, conventional air spray or airless spray depending on the product. Primers are usually thin enough to spray well and wet out a blasted surface completely.
Work at a consistent wet film thickness and avoid over-application at edges, welds and connections — sags and runs at these details are the most common primer defect.
Allow the primer to reach the specified state before overcoating. On some systems a primer should be topcoated while it is still slightly tacky for best intercoat adhesion; on others a full cure with an abrasion between coats is required.
Mixing, ratio and induction time
Two-pack primers are mixed in the ratio stated on the data sheet, typically 4:1 or 5:1 by volume for epoxy primers and 3:1 for polyaspartic systems. Allow the full induction time before thinning and application, and observe the pot life strictly — a primer that has begun to gel will not perform.
Cure, recoat window and service readiness
Recoat windows depend on temperature, humidity and film thickness, but a typical epoxy primer is recoatable after 12 to 24 hours at 20-25 °C and needs 7 days for full cure. Polyaspartic primers cure far faster and may be recoatable within 2 to 4 hours. Exceeding the maximum recoat interval requires the surface to be abraded and re-cleaned before the next coat.
Coverage and thickness calculation
Typical dry film thickness is 40-80 µm for a conventional primer and 60-100 µm for a high-build anticorrosive primer. At 60 µm, one litre covers roughly 12-14 m². Always measure the wet film and calculate back from the solids content to confirm the specified DFT is being achieved.
Technical note. Coverage (m²/litre) = (volume solids × 10) / DFT (µm)
Worked example
| Specified DFT | 35 µm |
|---|---|
| Volume solids | 45 % |
| Theoretical coverage | 12.86 m²/litre |
| Total for the area | 100 m² → 1285.7 litres |
Advantages
- Very easy to apply by brush, roller or conventional spray, with excellent wet-edge and levelling properties.
- Good adhesion to properly prepared steel, wood and masonry.
- Wide colour and gloss range with good colour retention in dry interior and mild exterior exposure.
- Economical relative to two-pack systems, with far lower application labour cost.
- Ultra fast-dry grades available for maintenance work where downtime is critical.
- Surface-tolerant antirust grades can be applied over prepared surfaces without full abrasive blasting.
Limitations and precautions
- Slow cure compared with modern two-pack systems, so full handling strength may take 24 hours or more.
- Limited chemical resistance — unsuitable for solvents, fuels, acids and alkalis.
- Not suitable for immersion in water or for submerged service.
- Poor UV and weather resistance relative to acrylic polyurethane; exterior enamels will fade and chalk faster.
- Requires warm, dry conditions with good air movement to cure properly.
Storage and shelf life
- Store in original sealed containers in a cool, dry, ventilated store between 5 °C and 35 °C.
- Keep away from heat and naked flames — alkyd solvents are flammable.
- Do not allow the material to freeze and keep the containers tightly closed.
- Rotate stock first-in-first-out and observe the labelled shelf life.
Safety, PPE and ventilation
- Work in well-ventilated areas and use an organic-vapour cartridge respirator for spray application.
- Wear chemical-resistant gloves, goggles and protective clothing.
- Remove all ignition sources. Alkyd solvents are highly flammable.
- Do not use in confined spaces without proper extraction.
- Dispose of solvent waste through a licensed contractor.
Quality control and inspection
- Check the surface preparation standard and the blast profile before coating begins — this is recorded on the inspection report.
- Verify film thickness by wet film gauge during application and by magnetic induction gauge or dry film readings on the completed coat.
- Holiday test the primer before overcoating, particularly over welds, connections and edges.
Pricing and how to order
Delshine quotes this product per square metre at a specified dry film thickness, or per drum/litre depending on the project. The material cost is usually the smallest part of the installed cost — surface preparation, access and application labour dominate. Send us the substrate, the service conditions and the required DFT and our technical team will return a full system recommendation with a firm price.
Alkyd coatings are priced per square metre at a specified dry film thickness, and the material cost is low. The total installed cost is usually dominated by surface preparation and access, so an alkyd system is often the most economical option for maintenance work on accessible structures.
Frequently asked questions
The questions below are the ones our technical team is asked most often about this product family.
What is alkyd paint used for?
Alkyd paint is used for general protective and decorative coating of steel and wood: structural maintenance, interior and exterior enamels, handrails, doors, gates, pipework and general fabrication. It remains popular because it is easy to apply, levels well, adheres reliably and costs less to purchase and labour than two-pack systems.
How long does alkyd paint take to dry?
Touch dry in 4-8 hours and recoatable in 16-24 hours at 20-25 °C with good ventilation. Full cure takes several days. In cold, damp or poorly ventilated conditions these times extend significantly and the film may remain soft. The ultra fast-dry alkyd primer grades are available where a much shorter turnaround is needed.
Can alkyd paint be applied over rust?
No, not over active rust. Alkyd relies on a dry, clean substrate for adhesion, and painting over rust traps moisture and the rust continues under the film. Use a surface-tolerant antirust primer such as the GDS06-18 on hand-prepared steel where full blasting is not possible, but remove all loose rust first.
Is alkyd paint suitable for outdoor use?
Yes, with the exterior enamel grades, but with expectations managed. Alkyd exterior enamels give good protection in mild environments but fade and chalk faster than acrylic polyurethane or fluorocarbon. For coastal, industrial or high-UV exposure, specify an acrylic polyurethane or fluorocarbon topcoat instead.
Can alkyd be used for immersion in water?
No. Alkyds are not designed for continuous immersion. For tank linings, potable water, ballast tanks or submerged service, specify an epoxy system — for example DSEH-701 for potable water or the epoxy phenolic and epoxy coal tar grades for chemical service.
Can alkyd paint be sprayed?
Yes, with conventional air spray equipment. Alkyd paints commonly need a small amount of thinner to reach a good spraying viscosity — add the correct thinner only in the amount needed, and add it to the paint rather than pouring thinner into the spray pot.
Related products
These products are normally used in the same system as the product described above.
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