Surface Treatments

Trislot can make different surface treatments on the grille, adapted to the application or for aesthetic reasons.
As it is almost impossible to illustrate the treatments with a picture, we advise to contact Trislot for further information.

Pickled and passivated

Our standard finish is pickling and passivating.

The corrosion resistance of stainless steels is primarily based upon the presence of at least 13% chromium in the alloy. In combination with oxygen, the chromium forms a dense chemically resistance passive layer of chromic oxide which protects the surface against corrosion.

Unfortunately, every mechanical treatment will damage the surface layer by contamination with ferritic matter, changes to the microstructure, development of stresses and a reduction of chromium content. In addition, any heat treatment, such as welding, will lead to scaling and discolouration. These aspects not only diminish the visual appearance of the component, but in particular reduce its corrosion resistance. A dense passive layer of chromium oxide can only form on a metallically pure surface.

Pickling and passivating cleans and restores the corrosion resistance of the stainless steel and thus considerably influences their service life and usefulness.

Pickled stainless steel profiles and welding seams are metallically pure, free of scale and discolouration, have full corrosion resistance and have a decorative satin metallic appearance.

Glass bead blasted

Glass bead blasting gives a very uniform satin finish to the stainless steel grilles.

Glass beads that are used for this treatment are just spherical pieces of glass sieve sized from about 50 microns (micro blasting).

Mechanically polished

Mechanically polishing happens with a 100~180 mesh abrasive. The polishing direction can be in the direction of the surface profiles, but can also be perpendicular to that direction.


Electropolishing is, in principle a reversal of the electroplating process. Metal is removed by applying a dc current to the anodically connected work piece submerged in a special acid electrolyte. Removal takes place without inducing stress and preferentially affects the surface micro-roughness. The surface becomes smooth and bright, and the edges of the profiles are smoothened.

This can be an expensive treatment especially for large pieces.

Copper plated

To change the appearance of the stainless steel grille to copper, copper-plating is used. First a nickel primer is used, before the copper is electrolytically plated on the stainless steel. Copper plate thickness is about 10 microns.This copper plating combines the strength of the steel with the copper appearance and is relatively not expensive.