Guide written by:
Lukas, Constructeur bois passionné, Marne
Rust attacks all untreated iron surfaces. If galvanizing or steel - stainless steel - is the solution against rust, iron paints and anti-rust products can protect a metal from corrosion. Rust remover and fixative are also effective in treating metals against oxidation.
- Primer and anti-rust
- Rustproof paint
- Rust converter
- Rust remover
What is anti-rust?
In contact with atmospheric agents such as air and water, most metals will undergo the process of corrosion that will at first simply change their appearance, but will more importantly deteriorate it in the long run: it is rust!
Very unappealing, rust is especially renowned for weakening metals - especially outdoors, which can prove dangerous when metals are used in supporting structures or parts.
There are two remedies to this problem: the use of stainless steel or simply applying a protective product to avoid any issues!
Anti-rust & Metal primer
A wide variety of rustproofing products are at your disposal to prevent - or at least delay - the corrosion of metals . Several options are available to you, it's up to you to find the product best adapted to each situation.
Aqueous phase or solvent phase
Anti-rust and metal primers are available in two phases. A solvent phase is more durable and efficient, but less environmentally friendly due to its composition and application, which can produce fairly strong odors and the emission of VOCs - Volatile Organic Compounds. An aqueous phase is very easy to apply, but its lifetime is shorter. A solvent product is recommended for outdoors, while the liquid products are geared for more indoor use.
Ferrous and non-ferrous metals
This is a question you need to determine before any purchase. Indeed, anti-rust agents act differently, some only on ferrous metals - cast iron, iron, steel - others on copper, brass, lead. There are however generally compatible products available.
Finally, rustproofing products sell under two different products. First in the form of a primer, that is to say a product applied in the base coat, which is then coated with one or two coats of paint. The second option is to directly apply a rustproof paint, with the finish of your choice - matt, glossy, satiny etc.
The anti-rust paint has two important advantages: a great time save, immediately providing you with the desired finish. It should however be noted that a quality primer is more durable for the protection of metals: it's up to you!
Application of a anti-rust products
Whatever the case, do not hesitate to lay it on all the areas of your rooms - even double the layers of application. The smallest missed spot, even very tiny, will allow for the re-appirition and rapid spread ofrust !
How to restore a rusty metal?
Rust converter for metal
A rust converter is used to neutralize the rust: its role is to cover it and to neutralize its harmful action on the metal. The rust converter is therefore used for metals that have already been attacked, in order to eliminate any further risk. After application, it is unlikely that rust will reappear and you will be able to apply a paint finish or varnish on your metals. Beware, however, your metal's rusty appearance will stick around if you don't precede all of this with a good sanding!
Unlike a converter, metal rust remover is a stripping product, which therefore needs a bit more elbow grease! The application of the rust remover is done with a brush or by soaking after going over it with a metal brush. It then protects the ferrous metals by meas of cold phosphating.
Rust remover is a very effective product for restoring any metal: after its application, you will only have to apply rust preventive primer or rustproof paint and you're set for a few years!Other products for metal
In the form of a gelor paint, metal cleaner is crucial in the restoration of metals that have received many layers of paint. Its use with the brush avoids a long and tedious sanding! Respiratory protection, protective eyewear and gloves are highly recommended!
For lovers of the decorative rusty trend! It is also possible to accelerate the development of rust and produce a very aesthetic rusty effect on your metals. Essentially only for decorative pieces, the rust activator is applied by brush or roller and must be rinsed thoroughly with water after impregnation.
How to paint a rusty metal?
To keep it simple, let’s say there are two main methods of restoring metal:
- The quick and economical solution is to clean and sand the iron, then apply multiple coats of anti-rustpaint. You choose the finishing of your choice and save yourself on the time on the prep;
- The long but durable solution, requiring the application of a rust converter or remover, a primer and then special paint metal. Tedious work but guaranteed to last!
In both cases, painting a rusty metal always requires preparation: at least brushing the loose rust with abrasive paper - of low value type 80 -, a metal brush or even a sander or grinder equipped with an abrasive disc with grooves - especially if you have large surface in need of stripping.
Rustproof paint is applied as a conventional paint, with a roller or a brush. It is crucial to respect the drying time between two layers as recommended by the manufacturer.
4 questions / answers about metal
Why does the metal rust?
First, the metal oxidizes and the iron rust - rust being the technical term for of iron oxide. Corrosion or oxidation is defined as a change in a metal when in contact with certain atmospheric oxidizing agents. It's the modification of a non-stainless steel metal's composotiion when in contact with water, wair oxygen or salt.
The oxidation of a ferrous metal results in rust, in copper it is gray green, and for aluminum; alumina. With this in mind, an larger than normal amount of rusting inside your home may reveal a moisture problem... so watch out! Keep in mind that the rust appears and spreads very quickly: you've surely mistakenly left a tool out in the rain and seen what it's like afterwards!
What metals do not rust?
All metals that are not iron, as rust is the technical term given to the oxidation of iron, just like copper produces a green-grey rust. Some metals have very good resistance to oxidants or a very minimal reaction - alumina, or aluminum oxide, is an visible, non-perforating man-made particle in aluminum.
The oxidation of zinc is comparable to the oxidation of silver, copper and aluminum and presents in the same way, with only a thin layer on the surface which makes the metal more dull, butit does not alter its durability. Stainlesssteel is the name given to a anti-rust steel - this label is due to its composition of less than 1.2% carbon and over 10.5% chromium. Galvanizing can also be used to treat metals against corrosion. Gold is the only metal to be stainless, only one small issue: its price!
How to remove rust from a metal?
Rust is removed with a rustremover, brushed on, or by soaking the ferrous metals once any loose rust has been removed with a metal brush - paired with the use of Personal Protective Equipment (PPE).
Can also be applied the rust converter which unlike the rust remover, does not remove the rust but neutralizes its development. In both cases, the ferrous substrate must be coated with an anti-rust paint and primer.
How to give metal a rusty look?
The rusty look is created thanks to a rust activator which accelerates the oxidation process . It can be sprayed or applied with a brush or a sponge.
As for other products: be sure to use the applicable protection for any application!
For anyone leading the fight against rust, restoring old pieces or simply curious for more DIY-tips, follow the links below for related accessories, advice from our editors and more helpful guides:
- How to choose your brushes?
- How to choose your paint roller?
- How to choose your paint, primer and undercoat?
- How to choose your painting tools?
- How to choose your paint gun?
- How to choose your sander?
- How to choose your sand and abrasive paper?
- How to choose your grinder?
- How to choose your grinder accessories?
- How to choose your decorative paint?
And to work safely:
Guide written by:
Lukas, Constructeur bois passionné, Marne, 36 guides
Après avoir quelques temps roulé ma bosse dans le bâtiment, notamment dans tout ce qui touche à la rénovation – peinture, carrelage, menuiserie, pose de cuisine et de salle de bain – j’ai décidé de passer un diplôme de « Monteur constructeur bois » et j’ai bien fait car rien n’est plus plaisant que de travailler sur une charpente ou de concevoir une maison en bois ! Tout ce qui touche au travail du bois me passionne, et construire ma propre maison dans ce matériau est un de mes buts ! Je suis également un adepte de l’outillage du bâtiment : j’adore m’informer sur les innovations, les méthodes d’utilisation, les astuces ou les performances de chaque nouvel outil du marché, que ce soit en rapport avec le travail du bois ou non ! Je me ferai un plaisir de vous conseiller et de vous aider dans vos choix ! Bon bricolage !