Restoring iron railings; primer+paint or Hammerite(etc) directly on metal?

[MrJof]

Hello again.

I've not seen a good answer to this question online. Most of the DIY videos on restoring iron railings suggest removing the paint and rust, applying a primer and only after that a couple of top coats. But for small tasks over the years I've been using Hammerite directly on the metal with no problems l so I'm wondering if that's a wise route to take and save me some time. I tried to find a comparison (especially regarding longevity) but not seen much.

What are your experiences or recommendations? I'm happy to go the extra mile with primer if it means I'll not need to redo the job again in the next 10 years; there's about 20 meters of railings to refurb!!

Many thanks
Jof

 

[opps]

10 years sounds rather optimistic.

Hammerite has a life span of 8 years.

https://www.hammerite.co.uk/product/direct-to-rust-metal-paint-smooth-finish/

I would guess that the longest lasting on site finish would be achieved using an electrostatic spray gun, but they are super expensive.

 

[MrJof]

Thanks. Well, 8 years I suppose will have to do Either way if I can avoid completely re-doing it every 5 that would be nice.

In terms of primer versus direct-to-rust how do you rate the relative performance?

 

[sparkwright]

Sandblasting is the best way to prepare, but I appreciate this may not be practical.

Be sure the remove as much rust as you can, and sand the surface including old paint.

Two coats of Hammerite will ensure a longer lasting job - 4 hours minimum between coats. I prefer to get the second coat within 24 hours, to ensure it sticks, but that's just me.

 

[MrJof]

That's good advice, thanks. Sandblasting would but great, but as a substitute I was thinking of hitting most of it with an angle grinder with a cup brush and the details with files and a steel brush.

I have a vague feeling I read somewhere that Hammerite shouldn't be applied directly to bare metal though. Or was that someone being overly cautious?

 

[sparkwright]

You mean clean, unrusty metal?

 

[MrJof]

Yep, I remember someone saying shiny bare metal needs a primer first.

 

[sparkwright]

I had assumed this ironwork would be mostly rust!

If you can get back a lot of clean bare metal, then it would make sense to use an appropriate primer for iron on the clean bits yes.