Can Anodising Be Refurbished?
When items with anodised coatings are subjected to normal wear-and-tear or accidental damage it may be necessary to consider their refurbishment.
It is possible to locally protect bare patches (damage, jigging points) with chromate conversion coating or RoHS compliant alternative. This will not restore the appearance but will provide corrosion protection and can be painted.
For restoration of coating performance with good cosmetic finish then items can be re-anodised. Because of the need for electrical contact for anodising, any existing coating must be removed before items can be re-anodised (we do not offer ‘brush anodising’). Paint or lacquer that has been applied over the original anodised coating must be mechanically or chemically removed before anodising can be stripped. Removal of paint without damage to underlying material is a separate specialist service and not something we are able to undertake at MF. We may be able to advise on companies who provide this service, please contact us.
Anodising is removed using an etchant, which can result in a duller finish on stripped and re-anodised items. This can be avoided by re-polishing, linishing or otherwise mechanically finishing the surface after coating has been stripped and before re-anodising.
Any scratches, imperfections or pitting present on the material surface before anodising will likely be visible after anodising so mechanical finishing may be required to eliminate this. Any pitting will likely be a corrosion site even if the parts re-anodised. In general, anodised aluminium that has started to corrode cannot be restored by reworking to its original corrosion resistance. Although with significant material removal it may be possible.
Areas of bare metal respond differently when anodising is stripped. It is therefore best practice to have coating stripped first, then dress out scratches/dents.
Anodised coatings develop both inwards and outwards from the original material surface, this means stripping and re-anodising will result in dimensional changes. This may be a matter of tens of microns (growth on inside diameters, reduction on outside diameters) and will need to be taken into account where tolerances are tight. Depending on the geometry of the part it may be possible to mask areas with tight tolerances (such as bores) before stripping and re-anodising other surfaces. We can advise on all aspects of the stripping and re-anodising process – please contact us.
This page is provided for information only, it should not be considered advice and we cannot accept any responsibility or liability for your use of the information on this page. The information on this page is used and relied on at your own risk and you bear the sole responsibility for any outcomes. E&OE.