5.4.1 Grinding of metals
Objective:
Grinding is a mechanical surface treatment method for removing the uppermost layer of the substrate (e. g. rust) and exposing the actual base substrate.
Suitability:
Grinding can be carried out on all metals with the exception of coated metals (galvanised or metals coated with other materials). In these cases the layer that has been applied could be damaged by grinding. Take care with very thin substrates!
Procedure:
- Prior to grinding the surface must always be thoroughly cleaned and degreased, to prevent “incorporation” of the contaminants into the surface and making them thereafter very difficult or impossible to remove.
- Manually with an abrasive block or using grinding machines
- Grain size from K 120 to 180 is best for adhesive bonding applications
- After grinding remove all grinding dust, etc. from the surface (e. g. using a disposable, white cloth soaked with cleaning agent)
Points to heed:
- Regularly change the abrasive paper
- Ensure the substrates are cleaned beforehand
- Ensure the surface has a uniform finish
- Remove all residues and dust from the surface after grinding
