Demystify rustproofing

Demystifying rustproofing

Démystifier les antirouilles

Every rustproofing treatment as the same goal : prevents metallic components from rusting.  The way they work is simple.  Rust needs water (or humidity), air and metallic components.  Salt can accelerate the reaction.  The rustproofing coating separates the metal from the water and the air.  There are multiple types of treatment today depending on the needs of the customer. 

Rustproofing treatment types

Here are the 3 main category of rustproofing products : 

  • Annual;
  • Semi-Permanent;
  • Permanent.

ANNUAL : The annual treatment aims to protect for one year. It is base from oil, a thickener and anti-rust additives. It the best rustproofing for equipment or vehicles that already show rusting signs.  It will penetrate the rust and stop its progression. 

SEMI-PERMANENT : This category of rustproofing will aim to protect for up to 3 years. The main difference is the addition of an anti-rust wax and a solvent. It will create a flexible wax coating with higher durability than the annual rustproofing. It is the best rustproofing to use on equipment and vehicles without traces of rust and who are not brand new.

PERMANENT : This category of rustproofing aim to protect for more than 3 years, usually 5.  Its mainly composed  of anti-rust wax and once applied it becomes totally dry. It is important to use this type of product only on brand new equipment or vehicles without any traces of rust. The coating is not made to stop existing rust but to prevent it from ever forming on the metallic surfaces it protects. 


Generally, the rustproofing treatments are black or amber colored.  Some types of black rustproofing contain bitumen related component which help to stay in place longer and can give higher esthetic look.  Using a black undercoating will provide a "new paint" kind of feeling. Bottom line, the color does not provide advice on the overall quality of the product. 


There are more and more ecological rustproofing products offered on the market. Here are the two main types : 

  • Waterbased rustproofing.  Without any type of oil and solvent, this type of rustproofing has a high ecological value. The overall efficacity is mitigated, the application is more complex and the drying time much longer. 
  • Biodegradable oil based.  This category of rustproofing can also be divided based on the composition and efficacity of the product. As for the conventional rustproofing, they can be annual or semi-permanent if they use solvent and wax coating or not.  We believe it is the best environmental rustproofing product for the customer as it gives an equal and sometime even higher protection than conventional rustproofing. 


Many car dealership offer this type of product. The equipment is installed directly under the hood and create an electrical field to protect the metallic elements from rusting. This process is mainly used in the marine industry.  It is easier to create an efficient and complete electric field with the water around the boat and because there are fewer types of metallic components. In the case of a car, the multiple components coming to the frame and without the water surrounding makes the efficacity les probable. The Federal Trade Commission and other organization have imposed fine to some manufacturer. 



The rustproofing equipment are very similar to paint equipment. The rustproofing "gun" is different and adapted to higher viscosity products. There are smaller equipments (Gun on 1L Can) and higher volume equipments (gun on 205L or on tank) depending on the needs of the applicator. We recommend systems with an independent air hose and product hose connected to the gun. They are a little heavier but you can adjust the shooting of the product much more precisely with set-up.  A precise spay pattern makes a more thorough coating and less fume in the application area. 

Different types of nozzle are mane depending on the area to treat. For example, a 360° hose and nozzle will be used in the rocker panel, a 180° in the bottom of the door panel, a large spray nozzle for the frame under the car, etc. 


The quality of application depends mainly on the person applying the product.  Even with the best quality of rustproofing product, if the product is poorly applied the protection will suffer.  We give training every year to the people applying our products. A good treatment doesn't happen in 15 min... 

Before proceeding, the technician must verify under that car that everything is clean and dry.  If not, he will clean and wait for it to dry because rustproofing cannot reach every inch of every metallic component if it's too dirty and the water can prevent it from sticking to the metal. 

During the application, every vulnerable metallic piece must be cover with the rustproofing product. The ideal quantity may vary from the size of the equipment/car and from the type of the product. We recommend about 0.002'' thick coating which gives about 3 to 4 liters for a car and 4 to 6 liters for a pickup or truck. Too much rustproofing doesn't mean better protection.  The quality of the spray pattern, the overall coating of every parts and the quality of the product are the 3 main ingredient to a well-protected vehicle or equipment. 

Daniel Laflamme, Ing. Chimique Expert en lubrification SINTO

Sinto Depuis 25 ans