Proper corrosion protection can help guard your clients' vehicles. Winter brine—the mixture of magnesium and calcium chloride used on the roads in colder climates—can be particularly damaging and harsh on a vehicle. Even if you don’t live in a cold climate, inadequate use of corrosion protection measures can contribute to the development of rust. During collision repair, incorporating corrosion protection measures like using weld-through primer, epoxy primer, seam sealer and cavity wax is an important part of helping to protect against the elements and ensure the long life of the vehicle you are working on.
WELD-THROUGH PRIMER
Weld-through primers are an important corrosion protection measure. When using weld through primers, keep in mind that zinc-based primers are a more suitable material to use on Toyota, Lexus and Scion vehicles than copper based primers. This is because these vehicles are manufactured using a zinc galvanizing process, and zinc primer bonds to the metal of the vehicles better. Zinc also seems more resistant to corrosion than other types of weld-through primers, such as those made with copper. To properly use weld-through primer, thoroughly clean surfaces with a suitable wax and grease remover. Then, coat any bare metal areas that are going to be joined together but won’t be accessible after welding with weld through primer.
ADDITIONAL WELD-THROUGH PRIMER TIPS
- Ensure there is a thin, even coating of weld-through primer and that it is not clumpy or overly thick in some areas.
- Allow the weld-through primer to completely dry before you begin the welding process. This gives the zinc the opportunity to properly bond to the material.
- Some weld-through primers aren’t solvent resistant and can be washed away during the cleaning process as the vehicle is prepped for primer and paint coatings. Test products beforehand to make sure they are compatible.
CORROSION PROTECTION TIPS
- Electro-deposition primer—also referred to as e-coat—is an excellent corrosion protection material and should be left intact whenever possible.
- Vehicle-specific seam sealer specifications are given in the Repair Manuals for Collision Damage.
- Clean the heat-affected zones around welds to remove burned or loose material and coat with epoxy primer and cavity wax if applicable. For additional information about corrosion protection, see Collision Repair Information Bulletin (CRIB) #186, Corrosion Prevention for Collision Repair.
