Guest Blog – Mesh Myths Busted

We are lucky enough to have a guest blogger in Phil Esteban, Manager of Stainless Steel Security for Alspec, who make Invisi-Gard, blogging for us this week. We blogged about the advantages of Invisi-Gard last week, in this blog Phil goes into more detail about the mesh used in their products. You can find out even more about Invisi-Gard at Take it away Phil!

Recently I was asked to comment on some claims made by our competitors, and I thought it would be a good exercise to talk through and explain my response.

The claims were mainly to do with our obsession with only using high tensile GR316 mesh in our InvisiGard product.


Galvanised mesh is heaps cheaper, lasts just as long, and won’t corrode because it gets powdercoated.

The only thing that is true about the claim is that it’s cheaper. A picture tells a thousand words so this photo shows a powdercoated galvanized piece of mesh compared with a sample of Invisi-Gard in frame, and also a small sample of our mesh unframed in the foreground. Both had undergone accelerated ageing in a salt spray booth for a total of 2000 hours. The results are clearly evident.


Marine steel has a higher rust resistance than naked 304 when immersed in salt water.

The answer is that GR316 doesn’t have to be immersed in salt water, it always has a higher resistance to corrosion than 304 and is in fact the main reason people choose it.


The advantage of choosing GR316 over lesser grades disappears when the product is powdercoated, as this treatment forms an impermeable coating which means you get a total corrosion resistant system.

In fact, all powdercoating is porous and allows the ingress of pollutants and contaminants to the base material. It is then up to the quality of the pre-treatment and the base material itself to provide corrosion resistance. Invisi-Gard sources it’s mesh and undergoes the same powdercoating treatment as many of the leading brands, while increasing resistance corrosion by virtue of our choice of only GR316. Finally, if you still believe the powdercoating is impermeable review the photo relating to claim 1 and remember the gal mesh was powdercoated prior to the test being undertaken.


The big advantage that GR304 brings to the table is its strength. It has a higher tensile strength and elongation factor than 316.

The grade difference is mainly due to the chemistry of the steels, not the mechanical properties. In fact, the mesh used in Invisi-Gard has a pre-woven wire tensile strength some 100 megapascals higher than the 304 material. As far as elongation is concerned, a finished Invisi-Gard mesh product will withstand a deflection of 200mm without breaking, more than enough to cope with any security application.


Some competitors claim that they don’t build boats.

Well, neither do we.