DNA Anodising and DNA Machining and Manufacturing


8/2 Industry Place, Capalaba QLD

Ph: (07) 3245 2488     

Est. May 2016

Surface Preparation for Anodising

When an item is anodised, it will show the surface exactly how it is. I.E. If the surface has sand marks or scratches in it, they will be present once anodised. If the surface is polished and in excellent condition, it will show this when finished.

It is for this reason, that we advise you to prepare your products to the finish you require. Our staff do make slight adjustments to a finish such as smoothing out a scratch, but unless it is requested by the customer, it will be anodised "as is".

Please refer to the "types of finishing" page for assistance with the type of finish that meets your requirements. If you require further assistance, please feel free to contact our staff.

Common Issues with Preparation

Alkaline etching

This is caused in one of two ways

1. The item is machined with a coolant that is alkaline. 

Some coolants within machines have a PH between 8 - 9.5.If left on components, this can cause etching that is unseen by the eye. Once the component is etched within our processes, the etching is seen as black spots on the surface. Once the etching has occurred, it can not be removed without further machining.

2. Item is wet from the coolant or an alkaline/acidic substance, and placed on a surface that does not draw the moisture away from the component.

Two of the worst aluminium grades for this are 2xxx and 7xxx series and tends to occur on the machined end grain of the metal. 

There are a number of ways to alleviate this.

A. Use a PH neutral coolant.

B. Wash the component in warm water straight after machining and before storage.

C. Do not leave a wet item on a bench. Place the item on a moisture absorbent surface such as a rag, towel or cardboard.