When should I use primer when spray painting?
I am one of those who doesn't use primer very often, but there are times when primer is practical before spray painting.
09/07/2019
When I am doing projects where I'm going to be spray painting, I don't always use a primer before applying spray paint. But there are times when a primer not only helps the painted finish to look better, it also extends the life of the painted finish.
Most primers are specially formulated to stick to metal, plastic or other material. The primer bonds with the substrate to provide better adhesion for the spray paint finish. When I'm spray painting on wood I rarely use a primer, but painting on metal, and especially metal that is rusty, is a different story.
A good example of when to use primer is this project by Michael Alm. This rusty steel cabinet was bought on the cheap and he turned it into a storage organiser for his DIY workshop. You can see that the original cabinet didn't look like much and was covered in rust, but after some cleaning up and applying a spray paint finish, the storage organiser looks almost brand new.
Prep for a lasting finish
As with most projects in and around the home, preparation is the key to a long-lasting and perfect finish. All the individual pieces in the steel cabinet were scraped and sanded to remove rust. It is essential to remove this, as leaving it will only cause the spray paint finish to fail, which means you have wasted time and money on the project.
Prime before painting
After sanding and removing as much of the rust as possible, you only need to apply a single coat of primer. However, do make sure to completely cover all the areas where rust had started to form. Let the primer serve its purpose, which is to seal the finish and prevent rust from reoccurring.
Another benefit of using a primer is that it cuts down on the number of coats of spray paint you need to paint the entire item. After applying primer you will immediately notice that less spray paint colour is needed. So, while you have to buy a can of primer it cuts down on how much spray paint colour is required. And you can keep what's left in the can for other future projects.
Apply spray paint evenly
For a perfect spray paint finish, hold the can about 30cm away from the surface and spray from side to side, slightly overlapping each row for perfect coverage.
Once the paint was dry, new hardware was added to the drawers.
Michael also built a mobile unit that would house the steel cabinet and also provide additional storage.
Just goes to show... you don't need to spend a fortune to have storage!
