Bondall Ranex Rustbuster

[Tonyz]

Ranex Rustbuster converts rust from a detrimental oxide to a beneficial phosphate of iron.

Have been asked to help clean up old widows place and the deck & step rails have rust problems, not just surface but has not eaten its way through.

Is this stuff any good? or what other things should I try?
Money to spend is short in all directions.

[Beardy]

It works very well to clean it up before doing some form of protective finish. The surface will rust again if you don’t protect it

[BobL]

The active ingredient in Ranex is Phosphoric acid (PA) and Ranex only contains between 10 and 30% PA.

Ranex costs $30/L but for $22 at Bunnings you can also purchase a litre of Chemtech rust converter that contains between 30 and 60% PA

I personally don't like either all that much as they also contain too much detergent (OK that does help wet the surface) that unfortunately also produces a residue when it dries - OK it can be washed off but then the steel starts rusting again.

In your application a detergent residue might not matter that much but if you want a really smooth finish then for $28/L I use the 85% PA (for food grade hydroponic use) from ebay see Phosphoric Acid 1L Food Grade Hydroponics,swimming Pool, Rust Removal | eBay (https://www.ebay.com.au/itm/Phosphoric-Acid-1L-Food-Grade-Hydroponics-swimming-Pool-Rust-Removal/383391875982?hash=item5943efc38e:g:7AsAAOSwHfxeF8xI) This has no detergent in it but if needed you can always transfer some to a temporary container and add a couple of drops of dishwashing liquid. Just watch out, as 85% is pretty strong and will make a mess of any terrazzo etc. Also don't wash it off - let it dry and paint straight over the top.

[Tonyz]

thanks guys very helpful advice, looks like the Ranex as she has that already...lazy SIL bought it but got no further.

[aldav]

thanks guys very helpful advice, looks like the Ranex as she has that already...lazy SIL bought it but got no further.

Luckily she has a self starting dynamo of a B-I-L to rely on then. :D

[Chief Tiff]

Make sure you chip or scrape of off any scale; PA loves a light coating of rust but can’t work its magic through layers of it. My preferred method is to hit it with a carbide scraper and some elbow grease.