Please find information below and frequently asked questions related to both galvanizing and powder coating.
What is the size of your galvanizing bath?
|7.2m long||1.7m wide||2.75m high|
Contact sales team for any technical queries.
How long does it take to galvanize steel?
Is there an express service?
What life span can I expect from galvanized material?
Why is some galvanized material shiny and some dull?
Protection is equal - and often better - with dark grey coatings than with light grey coatings.
When rimmed or aluminium killed steels are hot dip galvanized, compact zinc-iron alloy layers are formed and covered by zinc, which has a light bluish grey lustre. In some cases the zinc can form randomly oriented crystals to give a 'spangle' finish but this is not a sign of either good or poor hot tip galvanizing, nor does spangle affect the corrosion resistance of the zinc coating. Silicon, which is sometimes added to steel as a deoxidant during its production, speeds up the reaction between the steel and molten zinc. When the steel part is removed from the galvanizing bath but still remains hot, the reaction may continue and convert all or part of the surface zinc layers to zinc-iron alloys.
Zinc iron alloys are dark-grey compared with the light grey of zinc and are more abrasion resistant.
Usually zinc-iron alloy coatings form more thickly and hence give longer life than the coatings on rimmed or aluminium killed steels. The zinc-iron alloys in any case have at least as good corrosion resistance as zinc, thickness for thickness can have better intrinsic corrosion resistance in acid industrial environments. These thick coatings can be more susceptible to mechanical damage particularly if handled roughly, and appropriate care must be taken.
The dark grey coating surface may develop iron oxide staining on atmosphere exposure, even in mild conditions when moist. This is only a surface effect and does not develop into nodular or flaking rust: the galvanized coating remains intact to protect the steel.
I have material that has been galvanized, its appears to look rusty, why?
1. Direct contact of galvanized parts with unprotected or inadequately steel (e.g. galvanized steel sections fastened with unprotected, electroplated or painted steel bolts).
2. Deposits of iron dust and swarf from other operations or sources onto the galvanized surface.
3. Water draining from unprotected or poorly protected steelwork, e.g. from damaged areas on painted steelwork.
4. During pickling, hydrochloric acid may penetrate into the weld area via pin holes or if the welding is intermittent. Residual salts can sometimes pick up water and cause 'weeping' from the weld areas. This effect is normally limited to a small area, ceases after a short time and is not detrimental to the coating.
5. Rusting of areas welded after galvanizing and subsequently left unprotected or inadequately protected.
6. Staining of galvanizing can occur when water runs off other materials notably metals such as copper, certain hardwoods, e.g. oak, an indeed whenever water can dissolve materials from one surface and redeposit on the galvanized steel.
How can I avoid this?
Welds should be continuous and slag-free wherever possible to minimise the retention of pickle residues.
Design structures to avoid run -off water from other metals on to galvanized steel. In particular avoid run-off from inadequately protected steel and from copper.
Where welding after galvanizing is necessary, welded areas should be thoroughly cleaned and the zinc coating restored either with an appropriate thickness of zinc rich paint or with a proprietary repair compound, in accordance with section 6.3 of BS/IS EN ISO 1461.
What is Remedial Treatment
How do you repair damaged areas?
a) Thoroughly wire brush the affected areas and apply several coats of zinc rich paint to give a coating thickness at least equivalent to the original galvanizing.
b) Thoroughly wire brush, heat the bare area with a blow torch to 300C and apply a special zinc alloy rod.
Painting with zinc rich paint is usually simplest but if a colour match is important, the zinc alloy rods are usually most suitable.
Contact the sales team for technical queries.
Powder Coating FAQs
How long does it take to powder coat material?
Contact us at the early stage in the planning process so that we can advise you on suitable methods of design and fabrication. Many delays are caused by inappropriate design and a lack of understanding of the powder coating process.
Is there an express service
Contact our sales team for more information
Why should I powder coat material instead of wet paint?
This modern surface coating system is a high quality finish application that is extremely decorative and more resistant to chemicals, chipping, peeling and wearing than other finishes.
The quality systems in our powder coating division have enabled us to obtain Qualicoat Approvalship - the highest European standard in powder application.
We are an approved applicator of Akzo Nobel - interpon d and Dupont powder - a proven powder finish system that has been tried and tested throughout the industry for over 10 years.
We can pass on our confidence in the outstanding quality of product and service through our unique extended guarantees. Contact our sales team for further information.
Generally powder coating life expectancy is approximately 25 - 15 years, depending on the material. Though in areas where the coating may come in contact with concentrated atmospheric pollutants [marine, chemical], the life expectancy would be shorter due to the environment. Please contact the sales team for technical information.
What colours can I powder coat?
Can you repair damaged areas?
Cleaning and Maintenance of powder coating.
Regular cleaning, on a maximum 3 month interval or to a mutually agreed timescale, using warm water and mild detergent. Abrasive cleaners including strong solvent must not be used to remove any heavy soiling. Where spirit should only be considered if the mild detergent is not strong enough.
In areas where the coating may come in contact with concentrated atmospheric pollutants [marine, chemical] it would be prudent to clean more frequently, E.G monthly.
Full documentation of the cleaning schedule must be maintained.
If damage occurs to the coating, repairs must be carried out immediately, contact N.K. Coatings Limited.
What size can you powder coat?
|6.8m long||0.850 wide||2.8 high|
|6.6m long||0.800m wide||2.7m high|
What colours can you offer?