Semi-Hard Anodising



Semi-Hard Anodising


Semi-Hard Anodising


Semi-Hard Anodising

The semi-hard anodising process was devised to satisfy the requirements for a hard surface finish combined with good colour options. Semi-hard anodising provides increased hardness, good adhesion, electrical insulation, heat resistance and increased corrosion resistance. Semi-hard anodising will usually result in a slightly lower surface finish to that of the original component but can be more easily dyed than the full hard anodised finish, giving a greater range of available colours.

Maximum Size Criteria

The table below outlines the maximum size criteria for semi-hard anodising:

1829mm (6')
1829mm (6')
910mm (3')
910mm (3')
910mm (3')
910mm (3')

*The maximum sizes for all other colours should be discussed with us in advance as our dye tank sizes vary.

Coating Thickness

Typical surface thicknesses of 20-30µm are achievable through the semi-hard anodising process.


The following sealing options are available for semi-hard anodised components:

Colour Dyes

Colour options are available with semi-hard anodising for an additional charge. We use the selected colours below from the Clariant dye range although other colours are available for large orders:

Aluminium Orange
Aluminium Bronze
Aluminium Fiery Red
Aluminium Bordeaux
Aluminium Violet
Aluminium Green
Aluminium Grey
Deep Black

Please note that these colours are meant as a guide and no guarantee can be made for a match between this online colour swab and the final colour. Also, due to the varying nature of alloys and dyes, we cannot guarantee colour consistency between orders over time or even across large batches.

Metro Engineering and Plating Works Ltd - Unit 3 - Chartridge Development - Eskdale Road - Uxbridge - Middlesex - UB8 2RT - UK
Tel: 01895 254666 - E-mail:
Sulphuric Acid Anodising - Chromic Acid Anodising - Hard Anodising - Chromate Conversion - Alocrom - Stainless Steel Passivating
Middlesex - Berkshire - Hertfordshire - Buckinghamshire - Oxfordshire - Hampshire - Surrey - Bedfordshire - London
Reading - Slough - Heathrow - Staines - Hounslow - Hillingdon - Bracknell - Maidenhead - Northolt - Harrow - Rickmansworth - High Wycombe - Yiewsley - Harlington - Perivale