Difference "Galvanised" and "Primed" Steel

[Fr_303]

Whats the difference between "Galvanised" and "Primed" Steel?
I need to make some brackets that are going to be exposed to the weather. which steel should I use?

[silentC]

Galvanised steel has been treated with a coating of zinc which protects it from rust. Primed steel I can only imagine has a coat of metal primer applied, presumably on the assumption that you will want to paint it. I would go for the galvanised steel - which incidentally can also be painted but it's not necessary. The 'primed steel' might also be galvanised but you'd have to check that with the supplier.

[DJ’s Timber]

Galvanised is fully protected from rusting whilst primed steel needs to be further coated with appropriate coatings to protect it from rusting, most primed steel coatings are porous so it does nothing to protect it from the elements.

So I would used galvanised.

[rod1949]

Depending on the severity of your environmental conditions another option is to make them from plain steel and then have get them Hot dipped galvanized this gives the ultimate protection.

[malb]

Primed means that the tube has a thin coat of paint sprayed over it as it comes out of the forming process to stop rust setting in immediately. Primer is generally a blue colour, but I have seen other colours as well.

Primed or Gal is rather academic if you need to cut, drill or weld the metal as in each case raw metal will be exposed and need some form of treatment for ongoing protection.

Gal gives off nasty fumes if welded or ground, as does the paint on primed steel when welding.

For long term protection, I would consider fabbing from plain or primed, followed by sand/bead blasting, hot dip galvanising, and possibly a coat of epoxy paint to finish if required.

If you are using a tube rather than solid stock, do not seal the tube. Hot dipping involves immersing the component into molten zinc to coat the surface. If a sealed hollow component is dipped, the air trapped within expands considerably and can rupture the tube, blasting molten zinc around the factory. It helps to discuss the project with the gal plant before manufacture to ensure that the units have appropiately sized drain holes. If you submit a sealed tube item, the gal plant will either drill to their requirements without consulting you, or reject the job. Similar conditions normally apply to powdercoating as well.