Best primer to paint steel

[giddyup]

I want a pergola built at the front of the house and wondering if it might be better to build from steel rather than wood. Wood is expensive here and you also have termite problems. The steel will need to be painted in a colour to match the house, but a good primer will be needed first. Any recommendations?

[Artisi]

Saw some undercoat / primer yesterday in Home Pro, it was labelled  something like 

" Galvanised " or similar - didn't pay all that much attention but could be worth checking out. 

[bankruatsteve]

The red oxide is used a lot but I don't like it.  Have to thin it down or it coagulates making a lumpy surface.  And thinned it doesn't seem to coat very well.

 

Then I started using "Duck" brand with is a silver color and that was good until it too starts to coagulate (after a few weeks) and same problem as above.

 

Last time I went in, Duck was out of stock and the sales guy let me to the cheap one "SaveD".  I was skeptical at first but really like it.  It is a white color, puts down a nice one coat primer (being deft with the brush).  And so far, it hasn't coagulated or even looked like it needs thinning.

 

[jadee]

I like Rust-Oleum, you can get it from Home Pro. There's a spray version that combines primer and undercoat that's pretty good. Covers really well compared with others. 

[bankruatsteve]

17 minutes ago, jadee said:

I like Rust-Oleum, you can get it from Home Pro. There's a spray version that combines primer and undercoat that's pretty good. Covers really well compared with others. 

Agree.  But, if used as a primer for eventual top coats of enamel (or whatever) it is very expensive alternative for that purpose. 

[Yellowtail]

Best in what way? The absolute best primer I have used in my life is TOA RusTech, and I've used hundreds of gallons of it.

 

But it is expensive, has to be mixed pretty precisely  and has only an 80 minute (if I remember correctly) pot life. We mostly sprayed it, but it brushes and rolls well too. 

 

I If you wan to brush or roll on an inexpensive primer and want to re-coat with a decent gloss enamel, I would go with the TOA red oxide primer and finish with their Glipton (Clipton?) enamel. I've had good success with these products on fabricated steel products.

 

I would also recommend using channel and angle rather than tubing and prime the the sticks before you and after you cut them up and weld them together. Ideally, you could use an intermediate gray base coat between the red oxide and the finish coat, particularly if you're going with a light color.

 

 

[CGW]

If you want a lasting primer you need to use a two part epoxy primer, this is all we use for offshore coatings, "Jotafix Epoxy Primer" is available locally.

[bankruatsteve]

6 minutes ago, CGW said:

If you want a lasting primer

What does that mean?  A primer that does not need an overcoat?  Or...?

[shaemus]

Are you going to use Galvanised steel? Its not much more expensive. 

 

Turbo galvanising primer is available in white grey silver and black. Ot quite good. And also in spray cans. 

 

The jotun range (yellow cans) is a very good paint. I used thier oxide primer and a 2 part polyurethane paint then a top coat. 

 

Surface prep is what makes your coatings last. 

 

 

The alkld enamels are synthetic a s very hard wearing and pretty cheap 

[Tarteso]

I am thinking to build a Small Pergola with Aluminium...and try to avoid the oxide, but must to check the price. 3x3 m. Will be enough.

[BritManToo]

I just let my steel rust, the steel is cheaper than the paint and probably lasts as long.

If they rust through, I'll just weld some more together.

These have been up 15 months ....... suspect they'll last at least 5 years.

Don't understand why the paint is so expensive here.

 

Edited September 13, 2020 by BritManToo

[bankruatsteve]

A racial slur and response containing it have been deleted.  I'm told that's rules violation.

[Andrew Dwyer]

I used this :

 

 

 

No problems in rusting in 2 1/2 years on a sala I built:
 

 

 

[transam]

I was in Dohome the other day and saw a new line of metal paint that came in a few colours, can even use on galvanized items, it was 500bht a gallon...

 

My front gate and railings will be seeing the stuff soon...

[Yellowtail]

57 minutes ago, BritManToo said:

I just let my steel rust, the steel is cheaper than the paint and probably lasts as long.

If they rust through, I'll just weld some more together.

These have been up 15 months ....... suspect they'll last at least 5 years.

Don't understand why the paint is so expensive here.

 

Some people like their stuff to look nice.

 

Paint is expensive here compared to where?

[Lacessit]

Use galvanised or Zinc/aluminium coated steel, then you won't need paint.

[transam]

1 minute ago, Lacessit said:

Use galvanised or Zinc/aluminium coated steel, then you won't need paint.

If it gets scratched up on instillation, which it will, rust will get going...

[CGW]

1 hour ago, bankruatsteve said:

What does that mean?  A primer that does not need an overcoat?  Or...?

It ages well!

The most difficult thing to achieve with a paint job is too achieve good adhesion, which is why sand blasting is the "best" surface preparation prior to coating, two part epoxy adheres well & is non porous, which obviously provides good corrosion resistance, top coat provides further protection from UV etc and you get the "finish" you want!

I see you don't like "Red Oxide" in its day, when there was nothing else it was ok, biggest drawback is it is extremely porous.

Edited September 13, 2020 by CGW

[transam]

2 minutes ago, CGW said:

It ages well!

The most difficult thing to achieve with a paint job is too achieve good adhesion, which is why sand blasting is the "best" surface preparation prior to coating, two part epoxy adheres well & is non porous, which obviously provides good corrosion resistance, top coat provides further protection from UV etc and you get the "finish" you want!

https://www.toagroup.com/en/product/product-details?url=toa-rust-tech

[Yellowtail]

1 hour ago, Tarteso said:

I am thinking to build a Small Pergola with Aluminium...and try to avoid the oxide, but must to check the price. 3x3 m. Will be enough.

Mill finish AL should cost about 4-5 times what steel costs 

[Yellowtail]

13 minutes ago, transam said:

If it gets scratched up on instillation, which it will, rust will get going...

 

Galvanized will generally not scratch through, and even if it does, and long as the scratch is less more that about 3mm wide it will not rust. The zinc corrodes galvanically protecting the steel until it is all corroded away.

 

Also, if you're using tubing the inside of the tube is coated as well.

 

Fabricated steel products welded together from hot-dipped galvanized sheet and tubing and welds coated with zinc-rich compound easily last 20 years in extreme summers and winters without significant corrosion. 

[Yellowtail]

24 minutes ago, CGW said:

It ages well!

The most difficult thing to achieve with a paint job is too achieve good adhesion, which is why sand blasting is the "best" surface preparation prior to coating, two part epoxy adheres well & is non porous, which obviously provides good corrosion resistance, top coat provides further protection from UV etc and you get the "finish" you want!

I see you don't like "Red Oxide" in its day, when there was nothing else it was ok, biggest drawback is it is extremely porous.

Red oxide is pretty hard wearing and burns off well when welding which makes it nice when pre-priming structural steel. 

[Susco]

Just use the normal red or grey oxide, but put a course of lacquer over it. Without the lacquer every primer will rust.....if exposed to moist or water

Edited September 13, 2020 by Susco

[CGW]

31 minutes ago, Yellowtail said:

Red oxide is pretty hard wearing and burns off well when welding which makes it nice when pre-priming structural steel. 

Indeed, when I was an apprentice 50+ years ago we used it, it was <deleted> then! now there are much better primers. ???? 

[CGW]

39 minutes ago, Susco said:

Just use the normal red or grey oxide, but put a course of lacquer over it. Without the lacquer every primer will rust.....if exposed to moist or water

How long would the lacquer last in the sun? not unusual for "paint systems" to last 10+ years now if properly applied and they come with a guarantee if your spending enough money!

[Susco]

7 minutes ago, CGW said:

How long would the lacquer last in the sun? not unusual for "paint systems" to last 10+ years now if properly applied and they come with a guarantee if your spending enough money!

There is no sun under a roof, and I was saying lacquer on top of the oxide primer

 

[Lacessit]

1 hour ago, transam said:

If it gets scratched up on instillation, which it will, rust will get going...

Has to be a scratch right through to the underlying steel, even then the sacrificial protection will keep it sound until someone decides to do a touchup with zinc-rich primer in the affected area.

IMO corrosion science is not your area of expertise.

[bankruatsteve]

2 hours ago, CGW said:

I see you don't like "Red Oxide" in its day, when there was nothing else it was ok, biggest drawback is it is extremely porous.

My issue with red oxide primer is mainly that it would coagulate (become gloppy - whatever) within hours after opening the can.  That needed thinning.  But then difficult to lay down a good coat that wasn't full of "glops" or so thin that needed 2nd, 3rd coat.  To me, a metal primer is one that prevents rust and makes a good foundation for the "color" coat(s).  Also, the red oxide primer that I have used will disintegrate over time (turn to a dust) if not applied a cover paint.  My question was if some primers (like maybe Rust-Oleum and the epoxy based) don't need a cover coat?  Which is not to say a cover coat is not needed for a certain color, etc.  Aagh.

[CGW]

3 hours ago, bankruatsteve said:

My question was if some primers (like maybe Rust-Oleum and the epoxy based) don't need a cover coat?  Which is not to say a cover coat is not needed for a certain color, etc.  Aagh.

I get what you mean, products like Rust-Oleum are more of a good quality "Hobbyist" paint? be expensive to cover large areas with, if you had a small gate to paint sure it would be fine - never used it, but for large areas a two part epoxy and a decent top coat would be the more practical, efficient and economic way to go! IMO

 

4 hours ago, Susco said:

There is no sun under a roof, and I was saying lacquer on top of the oxide primer

Why not just use a two part primer then a topcoat? ???? 

Lacquer does like sun or heat and starts to delaminate and crack quickly at the temps it would have to endure in Thailand, be difficult for the OP to match the colour to his house also - as he requested, unless it's "red Oxide".

[Susco]

5 minutes ago, CGW said:

4 hours ago, Susco said:

There is no sun under a roof, and I was saying lacquer on top of the oxide primer

Why not just use a two part primer then a topcoat? ???? 

English is not my native language. To me lacquer is the same as a glossy/shiny top coat.

Edited September 13, 2020 by Susco