metal paints

[Drago]

I know no i'm being stupid to be considering something other than galvanise!!
For those in the know what is the best type of paint for RSJ metal work?
Why couldn't a polyurethane type paint be used for metal work? Would it actually bond to it even if it was primed. It works well on rough surfaces like concrete and but it says not suitable for smooth surfaces.
Tia

 

[MD @Minshall Buildings]

Successful painting is all about the preparation, as without a good key to the substrate( the steel) the paint will lift off eventually. If you can blast clean the area to be painted that is best but at worst use a wire brush to clean any rust or scale from the surface and ensure no surface grease before painting.
Next a good coat of zinc phosphate primer followed by another in your required top coat colour.

Paint is porous, so you will always need to re-coat over the years if you want to retain protection.................this is why galvanizing works so well in farming as its fit and forget ( unless you leave it in contact with acidic materials !)

 

[upnortheast]

The steel work in our silage pit was starting to show rust after about 6 years. We got some lads in with some serious grit blasting kit. They reckoned it needed the red oxide undercoat applied within 10 minutes of blasting.
When they were finished we gave it 2 coats of green paint by hand. That was 15 years ago & it still looks reasonable.
Moral of the story (as said in the previous post ) is to get it properly clean before you start with paint

 

[Drago]

thanks for the replies, I'll have to check with the fabricator for quality control r.e. painting make sure its done correctly.
Would hand painting allow for a thinker application or is preparation the overall key to longevity?
Its the extra cost of the galvinise - an extra 27%. Which making me consider paint .

 

[Deutzdx3]

Galvanise then epoxy prime then polyurethane topcoat. Company local to me paint wind turbines in that way, blast, prime, topcoat, they painted the Westminster bridge with a 25year warranty so done properly lasts as long as galvanise.

 

[Cowcalf]

If you know anyone who paints bridges that is usually top quality

 

[Shavings man]

Red oxide any good these days ?

 

[MD @Minshall Buildings]

thanks for the replies, I'll have to check with the fabricator for quality control r.e. painting make sure its done correctly.
Would hand painting allow for a thinker application or is preparation the overall key to longevity?
Its the extra cost of the galvinise - an extra 27%. Which making me consider paint .

Hand paiting would definately buil

thanks for the replies, I'll have to check with the fabricator for quality control r.e. painting make sure its done correctly.
Would hand painting allow for a thinker application or is preparation the overall key to longevity?
Its the extra cost of the galvinise - an extra 27%. Which making me consider paint .

hand painting will definitely build a thicker coating, but the key to longevity is the preparation of the steel. I'd suggest you need to weigh the up front cost of galvanizing with the probable ongoing maintenance of a paint coating over say 10-20 years?.............27% initial cost doesn't seem too bad then IMO?

 

[roscoe erf]

Successful painting is all about the preparation, as without a good key to the substrate( the steel) the paint will lift off eventually. If you can blast clean the area to be painted that is best but at worst use a wire brush to clean any rust or scale from the surface and ensure no surface grease before painting.
Next a good coat of zinc phosphate primer followed by another in your required top coat colour.

Paint is porous, so you will always need to re-coat over the years if you want to retain protection.................this is why galvanizing works so well in farming as its fit and forget ( unless you leave it in contact with acidic materials !)

bull shite

 

[MD @Minshall Buildings]

Red oxide any good these days ?

modern paints are all water based and the old red oxide was solvent based which folk claim were always better? The latest ones are pretty good actually.
I'd go for a good quality zinc phosphate primer/top coat and ensure at least a couple of good coats on a well prepared steel.

Red oxide any good these days ?

Red oxide any good these days ?

 

[MD @Minshall Buildings]

bull shite

apologies for trying to be helpful !

 

[Tonym]

If hand painting use a roller instead of a brush. Gives a much more even cover and is easy to get into the corners of the H section. It is also much faster than a brush.
For smaller sections use a mini roller.

 

[Deutzdx3]

Red oxide any good these days ?

Wouldn’t touch if if I were given it.

 

[Deutzdx3]

With hydraulic painting, it can be laid down thicker than hand painting, for instant, epoxy primer 1.5mm of paint from 3 coats. 1.5mm of topcoat polyurethane from 3 coats. Beever commercial who paint mammoth items use hydraulic pressure and the paint it applies is unreal,

Not all paint is water based.

We use epoxy which is the resin, polyurethane again that’s the resin, water in water based paint is just the carrier liquid that it uses to transfer the pigment to where you’re applying it.
Red oxide is my along the line of synthetic as it can be thinned with petrol not recommended though as it has to much water in it. If you want real advice, call up some one like international paints, they are one of our supplies or ppg. [emoji106]

 

[SilliamWhale]

I'm a big fan of linseed oil paint nowadays. Probably too pricey for RSJ's but its good stuff and goes a long way