The authoritative public forum
  for Metal Finishing since 1989
-----

Durability of Flash Gold Plating on Brass

March 5, 2010

Dear sir-
I'm writing you on behalf of a charitable Trust. We are a religious body and seek your advise on gold plating. We have a meditation hall wherein the interior is designed in shape of 18 gauge half hard brass sheets in the shape of leaves. There are about 2000 different brass leaves covering an area of 3000 sq ft. we are going to do a 24 carat gold plating on these leaves and below are the suggested process by the plater.

1) Brass leaves will be buffed first
2) Copper plating on leaves
3) Nickel plating on leaves
4) Gold plating on leaves (Flash dip in a GPC bath)
5) Electrophoretic lacquer coating

As per platter using above process the durability of the gold plating would be more than 10 years. The environmental conditions of the interior would be:

1) Centrally air conditioned hall
2) Not open to public
3) Dust free
4) leaves are over 10 ft ground height and are placed on ceiling. there is no scope where these are touched.

Would request if you could advise if the above claim of 10 years or more is correct on platters part keeping in view above conditions and processes.

This is extremely urgent and we would appreciate an immediate advise on this.

Thank YOU.. Jai

Jai Gogia
Buyer - Delhi, India

---

Dear Mr Gogia,

Normally Gold metal sheets/leafs of 50 to 100 microns thick stuck on with Gold paint onto the brass will last much longer than Gold plating. You can spray on a lacquer if you like.

Gold Plating will look brighter but will not last as long as the pure gold sheets. For the process described by you a maximum of 5 years is all you can expect. Staining and discolouration will start in two years/ peel off and corrosion spots within 5 years and total failure of the coating in 10 years positively.

Khozem Vahaanwala
Saify Ind

Bengaluru, Karnataka, India

March 10, 2010

---

March 13, 2010

At first glance, the plater's proposed cycle seems adequate to me. If the plating is done correctly, the only things that would cause degradation of the coatings would be the atmosphere in the room and a poor longevity of the particular clear coat. The electrophoretic clear coat would be the most important thing - it is what must last 10 years. I know little about clear coats, so maybe someone who does could comment. I don't know what the effect of incense would be on the clear coat.

Even with flash gold plating (I am assuming from .12 - .17 microns, the gold costs would be from $20,000 - $30,000, if my math is right. You could consider thicker gold but I don't if it would improve the situation.

Concerning the other post, I know of no gold leaf 50-100 microns thick. Gold leaf is typically 0.1 microns thick. Even at 0.1 microns, it would take about $60,000 - $90,000, or more, worth of leaf, assuming 1 to 1.5 sq.ft./25 sheets, and a lot of labor to apply it. If you do use leaf, I think it would be a mistake to clear coat it. As a hobby, I make hand-carved gold-leafed signs, with no clear coat. An outside sign I made 20 years ago still has 100% of the shiny gold intact, although the sign itself is falling apart.

Chris Owen
- Nevada, Missouri, USA