Gates, Railing and Wrought Iron Work.

Answering the questions, we get asked

What preparation should I undertake? What can be painted and with what coatings? What paint do I need? How long will it last? What care must I take? What do I need to consider? These are all relevant questions to most paints and protective coatings. In this blog we are aiming to talk in simple laymen’s terms and is directed at anyone and everyone in the hope that it will help you make the right choice in terms of paint.

How do I prepare the surface to be painted? This depends upon what is on the surface of the substrate currently. The following recommendations are fairly uniform whichever items you are looking to paint. It is generally accepted that shotblasting is the best method of paint preparation, “shotblast to SA 2.5” this is recognised shot blasting standard. Shotblasting is an ideal preparation as it removes old paint, rust, grease and other contaminates, it yields the additional benefit of roughening the surface, given any new paint an excellent surface to adhere to. Many customers will not have shotblasting facilities and so mechanical abrasion, using an angle-grinder or mechanical sander will have a similar effect in terms of rust removal and roughening the surface. If shotblasting or mechanical abrasion is not an option, the use of a wire brush and production paper along with a good helping of elbow-grease will certainly be better than nothing. It is good practice to wipe over any surface prior to painting with a degreaser and clean cloth to remove any possible contaminates transferred during the handling of the item to be coated. Ensure the surface is dry before painting.

Typical substrate you may encounter could range from

  1. Freshly manufactured items produced in mild steel.
  2. Previously painted items.
  3. Rusty mild steel or iron.
  4. Aluminium/Alloy.
  5. Galvanised.
  6. Powder coated items.

Surfaces 1, 2, 3 and 4 will be the “most likely” to be encountered by an end customer or refinisher, with items 5 and 6 more likely to be encountered on new or previously un-painted (wet painted) surfaces. Both Galvanising and powder coating are in themselves coatings. They are designed to be the finished coat, giving protection and appearance. It is only when the appearance needs “refreshing” or protection needs attention that an additional coating is sought.

What can be painted with what coatings?

  1. Freshly produced metalwork (new)

If the substrate is bare metal, uncoated and prepared as described above you have a varied amount of options based upon application methods, environment, longevity and of course cost. There are Primer-finish products such as the Manor Zinfos range or the Rustoleum CombiColor range that offer a primer and top-coat in one product. These are very cost effective but will offer compromises in protection and in some instances the availability on gloss level options. The more traditional method would be a protective primer/undercoat (Avenue zinc phosphate primer) followed by a high gloss pigments paint (Manor fast enamel) for that “brand-new” look. If a long coating life expectancy is required then a two-pack system offers greater protection and durability.

  1. Previously painted metalwork

If the item has previously been coated you would need to prepare the surface to ensure there is no rust, grease of contaminants and the existing coating is abraded to aid adhesion of the new paint. Any loose of flaking paint would need to be removed and bought back to a sound base with all surfaces clean and dry. The options then really fall into two categories.
Firstly, you can use a mild solvent-based coating with a fair degree of confidence that there will not be a reaction with the previous coating. This will give the added benefits of being low odour and slower drying, enabling a long “wet-edge” if applying by brush or roller (typical products would be Manor ZP24 primer and Manor single pack polyurethane). The alternative coatings are based upon a stronger solvent (Xylene) and will generally dry quicker but will be more aggressive and could potentially “pickle” or react with an existing coating. A small area should be tested to ensure there is no reaction and full adhesion is evident between the existing and new coating.

  1. Corroded metalwork

Any ferrous metal which has been neglected or poorly maintained will show a degree of corrosion/rust to a lesser of greater degree. The rust can be removed a described previously but an additional option, rather than an alternative would be to remove as much rust as possible, certainly all loose and flaky rust areas and then apply a rust neutraliser, we offer Blue steel and HMG’s ferrozinc. These are treatment that change appearance after application/cure and neutralises the rust. This surface can then be overcoated with a primer-finish or primer and top coat system.

  1. Aluminium or Alloy

The coating of aluminium/alloy is far more likely to be recoating/refinishing rather than new railings/gates/garden furniture. With garden furniture being imported and becoming available more cheaply, the need to maintain the appearance and protection is also growing. Preparation follows a similar path, remove any corrosion (tends to be a white/grey powder oxidisation rather than a red-rust associated with steel), grease and contaminants and abrade any sound existing coating. If there are large areas of exposed metal the use of an etch primer, like Manor’s 1k etch would aid the adhesion of the subsequent paint coatings. The same options are available in terms of paint systems as with mild steel, once the etch primer has been applied and has cured.

5. Galvanised metal.

If repair or a cosmetic change is required there are a number of processes to go through before a primer-finish or primer and top-coat system is used. New “hot-dipped” galvanising requires “aging”.  Mordant T wash is an acid etching solution that “ages” the zinc, turning it from a bright spangled finish to a dull grey-black finish. This process promotes adhesion on to the zinc while still maintaining the corrosion resistant properties. The use of a two pack etch or single pack etch primer gives further build and adhesion and is usually sufficient for use on abraded, aged galvanised products. Once the etch primer has cured the use of a primer-finish, single-pack primer and top-coat or two-pack system can be adopted for the desired protection and appearance. As with the primer-finish products there is a simple one-coat alternative finish that can be applied directly onto galvanised products. Manor have a High Build Vinyl which has excellent adhesion to difficult substrates including galvanised. This can be spray, brush or roller applied and is available in numerous colours. This is an excellent product, however its main weakness being its poor chemical resistance so care should be taken in certain environments.

6. Powder Coated items.

Powder coating is a finished coating and as such has not been designed to be over-coated, even with itself. Powder coating “chips” and can get damaged like any other coating and once the substrate is exposed to the elements corrosion will begin. In terms of repair and recoating, in an ideal world the item would be shot-blasted or stripped so that a completely new coating can be applied. This is not realistic in every scenario and so some basic steps can be followed that should afford you the ability to address the issue. The surface should be sound and any loose coating and/or corrosion should be removed. The surface of the metal and surrounding powder coating should be abraded, cleaned of all contaminates and allowed to dry. We have seen some success with Manor’s high-build vinyl as a finish coating and two-pack epoxies due to their respective adhesive properties. A single pack or two-pack top-coat can then be applied over the two-pack epoxy to give U.V. resistance. Powder is produced in various chemistries, polyester powder coating is softer than a full epoxy powder and so a small area should be coated and after cure, tested for sufficient adhesion.

What paint do I need and how long will it last? These questions have been grouped together as the end location and application methods can dictate the expected performance. If the item is going to be near a coastal location or face a high amount of sunlight, careful consideration will need to be taken in terms of salt-spray and Ultra-violet resistance or the need for constant maintenance should be expected. A two-pack paint system, in terms of primer and top-coat will afford the best performance in terms corrosion and U.V. resistance but will cost more, require PPE and suitable application environment if application were via spraying. In less “hostile” environments brush and roller applied single pack paints perform well in terms of appearance and rust prevention.

What care must I take? Preparation is generally the same, remove corrosion, contaminates, grease, oil etc. Ensure any existing coating is sound and the whole area coated or un-coated is abraded. Ensure all surfaces are clean and dry. Test a small area to ensure adhesion and that there is no adverse reaction with the existing paint with the intended paint.
Some typical products and systems in relation to what we have described above. Following preparation, removing corrosion and containments, surfaces abraded and tested and ready to go.

Primer-finishes (protection and colour in one product)
Manor Zinfos340, White spirit based (mild solvent), available in numerous colours, low odour and suitable for roller or brush application. Only available in a 50% gloss level.
Rustoleum CombiColor white spirit based (mild solvent) low odour suitable for brush, roller or spray application. Available in gloss, satin or matt sheen levels.

Primer and top-coat systems,

1. Manor ZP24 zinc phosphate white spirit based (mild solvent) low odour primer available in red or grey. This can then be over-coated with Manor’s single pack polyurethane white spirit based (mild solvent) low odour gloss top-coat.
2. Avenue Zinc Phosphate primer, xylene based (fast drying) in red or grey. This can then be over-coated with Manor Fast enamel, available in a full array of colours in a full gloss.

High Performance system.

1. Sigma Sigmacover 522 is a two-pack M.I.O. epoxy primer with high corrosion properties in a green/grey metallic finish. Application by brush, roller or spray. Overcoated with Sigma Sigmadur 550H, this is a two-pack polyurethane gloss topcoat Application by brush, roller or spray.

Specialised related products.

  • Avenue Blue steel is a long establish single pack water thin-able rust converter. Milky white in appearance turns black when rust has been neutralised.
  • HMG Ferrozinc is a similar product to the blue steel. Milky white in appearance, turns brown when rust has been neutralised.
  • Ardenbrite is the best-selling metallic paint extensively used on railing finials where the bright gold appearance is desired. This is our best-selling product for railing and gate decoration as it is a true “bright metallic” and not the “bronze-gold-copper” or “pewter silver” as found on more cost-effective products.

Avenue group offer a full range of tools, abrasives, PPE, Sundries and coatings, everything you need to ensure a professional job is done.

 

 

 

 

 

 

 

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