Protect from rust

Protect perforated sheet from rust

Shown left: within weeks this will be rusty.

This is a popular design for fixing perforated sheet. However it is a very bad design for avoiding corrosion. The visible area of perforated sheet will be well protected with the Tri-Resin System, however the inner face of the folded edging will start to go rusty in a matter of weeks.

On close observation it can be seen that it is not painted. This is because there is no practical way of getting the paint in there, leaving it with no protection. To compound the problem, water will fill the bottom edging. Within a year, this may need replacing. If this is an obligatory design, stainless steel should be used with drain holes. Once painted introduce oil, or wax oil, this will help protect the un-painted areas.

Distortion when galvanising mesh

Shown left: heat from galvanising causes distortion.

If galvanising is to be used, then for best protection the component should be manufactured and galvanised prior to powder coating.

Distortion of thin material should be considered. Pre-galvanised mesh can be an alternative, but be aware of over lapping areas that are not galvanised and are made in such way that it is impossible to paint between. Powder coating cannot be relied upon to fill gaps, or act as a sealer.

No paint, no protection

Shown left: an inaccessible area for spraying.

It is important to consider corrosion protection during the design stage. Where there is no paint there will be no protection. This area of over lap could have easily been remedied by using the same size channel or removing the bottom web and fully welding.