Which Paint To Use On New Galvanize Rail

What is hot dipped galvanized metal and why do people apply it?

Before nosotros get into how to paint over galvanized metal, permit's give a really quick background into what hot dipped galvanizing is and why people would do it.

Stair parts being lowered into a bath of molten zinc

Hot dipped galvanizing is a process that involves dipping steel into a bathroom of molten zinc. This process creates a blanket that is metallurgically bonded to the steel, in essence becoming the outer layer and part of the steel itself.

Stair components coming out of the zinc bath

The galvanized coating adheres to the steel at effectually 3600 psi, where other coatings, like zinc rich painting and zinc plating, adhere to the steel at a rate of 300-600 psi at all-time. The hot dipped coating has a hardness of between 170-250 DPH (Diamond Pyramid Hardness) every bit compared to the soft not-abrasion resistant coating of zinc rich paint or a 75 DPH hardness of zinc plating. This is important as it shows why hot dipped galvanizing is such a popular means of corrosion resistance equally opposed to other coating options out there.

How do I pigment over hot dipped galvanized steel?

If you are looking for a end other than the shiny or dull galvanization finishes (there are corrective differences between each in luster, but no corrosion difference between the two), you would need to exercise a duplex, or two part, end to your production: a hot dipped galvanized base layer and a painted top layer.

In order to pigment galvanized metal you will need to outset know whether the steel is:

newly galvanized (nether 48hrs exposed, no zinc compounds built up on outside of steel),
partially weathered (day 2 to one yr, some zinc compounds built up on outside of steel also as possible dirt, grease, grit, etc.)
fully weathered (one yr on, zinc compounds roofing the entire surface.)

If the galvanizing is new y'all volition need to profile the surface to give the paint something to adhere to. You will as well need to grind down whatever bumps or drips that may exist present from the galvanizing process equally these volition show through the paint. Call back: Have care not to grind away the entire galvanized coating; using a hand grinder may be all-time practise to control pressure and grinding depth. For a partially weathered galvanized surface you lot will too demand to remove any drips or runs, also as the congenital upward zinc compounds on the surface. For fully weathered surfaces you lot can skip those steps as the built-up zinc compounds are proficient for helping the paint adhere.

After you accept profiled and/or prepped the surface yous will need to make clean the oil, dirt and other compounds from the steel. You lot can wipe downwards the handrails using a production like "simple light-green" to ensure there is no oil or other buildup on the textile. Then yous will need to utilize clean h2o to rinse the surface and dry it. Dry time to paint time should be kept to a minimum (under 12 hrs.) in society to avert allowing whatsoever other contamination or build-ups to occur.

paint galvanized metal stair crossover

Stair crossover with yellow paint over galvanized steel handrails and stringers

What are some paints that are available for utilise over galvanized steel?

After the surface is clean and profiled you lot are ready to pigment. A primer such as Sherwin Williams "pro-cryl" tin can exist used. This primer dries fast and is corrosion resistant. Y'all can summit coat shortly after that with an acrylic coating paint like "DTM". Check with your local pigment supplier for additional options, as well as to get re-coat and cure times based on your temperature, humidity and paint thickness.