UNDERSTANDING SEMI-PRECIOUS METAL

How do you know whether or not a bronze floor really is bronze, a pewter floor really is pewter, a brass floor really is brass, a yellow or white nickel-silver floor really is nickel-silver (German silver), or a stainless-steel floor really is stainless steel? Quite often you don’t.

For centuries, cheaper metals have been cleverly mixed and treated to resemble more expensive ones: the expression ‘fool’s gold’ springs to mind. Caution therefore needs to be exercised if you are buying uncertified semi-precious metals. It is not uncommon for some unregulated foundries to use scrap metal in their crucibles. If the foundry has the requisite colouring expertise, convincing results can be achieved.

Another key factor is the grade of metal specified. As any yachtsman will tell you, a stainless-steel anchor with rust spots is made from a lower grade of stainless steel than one without. All alloys are available in different grades. Only top-grade metals are used in the fabrication of an Element7 semi-precious metal floor.

As you would expect, Element7’s semi-precious metal floors are properly certified. Our metal is sourced from European BS EN and ISO accredited mills, it is fully traceable to its source.

Pricing a commodity

Copper, tin, nickel, zinc and antimony are all metals used in the composition of the various alloys available in the Element7 range of semi-precious metal floors. These metals are, of course, commodities and as such their price fluctuates daily. Any quote given for an E7 semi-precious metal floor is therefore only indicative. The final price has to be determined and agreed at the time of order, since that is when we reserve the metal for your floor.

Engineered backing board

In order to ensure ultimate dependability from your floor, the metal needs to be correctly bonded to an engineered backing board. The stability guaranteed by the backing board is essential.

The bonding processes required to glue the metal to the backing board can only be successfully carried out in a controlled factory environment; bonding the metal directly to the sub-floor on site is not an option. Only a specialist manufacturer can be relied upon to achieve a dependable result.

Metal adhesion

A recently constructed European museum, widely hailed as an architectural triumph when it was unveiled a few years ago, had some of its elevations clad in copper as part of its avowedly ‘modern’ look. Not long after completion, however, the copper cladding started to peel away – it was literally coming unstuck. The explanation for this is simple: copper and copper alloys oxidise. This characteristic causes manufacturers of industrial adhesives a major challenge: the higher the copper content of the metal, the worse the potential problem. Good bronze has a copper content of 95.5% and naval brass 67%. Likewise, metals that oxidise far less, such as nickel alloys or stainless steel, also have adhesion issues: being far less porous, they make it extremely difficult for glue molecules to achieve a reliable bond.

Another problem is ‘canning’. All sheet metal, including semi-precious sheet metal, is passed through rollers as part of the production process. A very slight curve – ‘canning’ – is unavoidably left in it as a result. Consequently, when sheet metal is glued to a flat surface, the adhesive used has to be strong enough to resist the constant spring-like pressure exerted by the sheet as it attempts to revert (re-curve) to its original molecular shape.

The etching primers and adhesives used by Element7 to bond the metal to its backing boards employ aerospace adhesive technology. The advantage of this is not only functional but aesthetic too. Crucially, not only is our adhesive completely reliable, it also negates the need to use fasteners (nails, screws or rivets) to secure the metal to the backing board.