Double powder coating vs. Powder coating vs. Hot deep galvanizing

Posted by Pedro L. Sanchez on Apr 26th 2021

For corrosion protection, hot deep galvanizing is considered the best option, no questions asked.

The galvanization process attracts zinc ions by electrolysis and pastes them onto the steel.

Zinc oxidizes much faster than steel, but its oxidation is a resistant layer that protects the steel from the elements.

The zinc layer is more robust than powder coating and even some epoxy paints and can easily overpaint.

But not too fast!

Hot deep galvanization has some significant disadvantages that made us choose powder coating as the best option for steel protection, especially for the Decorative Iron Business.

We sent our production a couple of times to get it galvanized, but we faced the following problems:

Cost

It is not efficient to send small quantities to the galvanizer. Galvanization plants have a high setup cost.

Quality

Scrolly pieces get lots of imperfections due to material accumulation and forced us to sand them down to make them look acceptable. We realized that there was no point in galvanizing if we had to remove the protective layer and then prime and paint.

Not only scrolly pieces present that problem but also smooth surfaces to a certain point.

The option was light galvanizing, but that will not do us any favor either because the layer is so thin that steel will not last much longer.

When you see fences that advertise galvanization, that is what you are getting. They offer you a five or even ten years warranty, but why? Because warranties are a commercial game, we know that most claims happen within the first year, and after five years, people have already forgotten whom they bought the product from or have lost the paperwork.

The environment

Although substantial efforts have been made in the last decades by the galvanization industry, galvanizing is aggressive against the environment, especially drinking water.

Powder coating

Powder coating is also an electrical process. The powder sticks to the steel until it is baked and cured, producing a solid protection layer.

To clean up the steel is of paramount importance to ensure proper adhesion.

Powder coating is robust and reliable if appropriately applied.

However, if the application is defective, it is no better than a bad paint job.

We preferred paint over powder coating for a long time because of bad experiences with powder-coated railings.

The fact is that numerous parameters can go wrong during the powder coating process.

For instance, if the gun settings are inadequate, the tight spots of the scroll work will not get powder; one powder particle will go to the left and another on to the right, leaving the in-between unprotected.

If the oven's settings are wrong (temperature and time), the piece will look good but soon enough will peel off like a boiled egg.

Now, given that the settings are all good if the powder layer is too thin, the powder gets toasted and becomes brittle, making it useless.

For that reason, powder coating needs to be done by a reputable professional that includes a good quality control step to the process.

That is why we do double powder coating, meaning two layers of powder, prime, and finish.

We use a zinc-rich primer before the finish coat that gives the color. We use the powder coating brand PPG, and the PPG primer's name is ENVIROCRON, tested for 4000 hours on salty water.

Our powder coating provider is great; they do an excellent job along with great service.

Double powder coating is expensive but worth the money.

In addition to the above-described benefits, powder coating generates negligible VOCs and virtually no air pollution, and it produces much less hazardous waste since it does not utilize solvents.

Moreover, it complies with environmental regulations and can be recycled. For these reasons, it is considered nontoxic and environmentally friendly.

We offer a one-year warranty on this finish, and we could quickly provide 5 or 10 years, but we prefer to be realistic; one year is enough time to know if we did the job did the job correctly or not.

If someone calls in 10 years, who knows what could have happened or what kind of use the iron balcony has had to endure.

We strongly believe that the finish we apply to our products is the best available in the market.

And the winner is... Double Powder Coating!

Written by

Pedro Luis Sanchez.

04/26/2021