Learn how to use rust inhibitor to prevent flash rust.
The water in the Dustless process can promote rust, but we can easily prevent this by using the Dustless Blasting Rust Inhibitor.
Not only does proper use of Rust Inhibitor prevent oxidation, but it also leaves a perfect paint or primer ready surface. It does not coat the metal, rather, it completely removes chlorides from the surface. As long as you don't recontaminate the metal, you'll be rust free for up to 72 hours.
How to Use
Blast with Rust Inhibitor Treated WaterAdd Rust Inhibitor to the blast water in a 1/100 ratio.
Rinse with Rust Inhibitor Treated Water
Use a fertilizer sprayer that screws onto a water hose and measures out the selected amount of rust inhibitor per gallon.
Or, with a mobile unit, add the rust inhibitor into the water tank, and use your built-in water pump and a hose to rinse.
Remove Standing Water from the MetalAllow the metal to dry completely. Use a leaf blower or compressed air to quickly remove any standing water from the metal.
Avoid Re-ContaminationDirt, body oil and moisture all cause rust. Be sure to wear clean rubber gloves when handling the metal and keep away from causes of additional moisture (like morning dew) if left out overnight.
Refer to the chart below to find out how much rust inhibitor you should use.
Quick Tip: Should you add Rust Inhibitor to the water storage tank or directly to the blast pot?
If you add inhibitor to the water storage tank, consider if you will use that water on any other jobs. You don't need Rust Inhibitor when you are blasting non-metal surfaces, so it would be a waste to use treated water on them.
Other considerations & tips
Using well water or hard water can affect how well the inhibitor works. You can combat this by adding more rust inhibitor, or filling up your tank elsewhere, with softer water.
Humidity in the environment
You also have to consider what's happening to the steel when you blast it. Angular abrasives, like glass, strip like a champ and leave a great anchor profile for a new finish. But creating those peaks and valleys also opens pores in the metal exposing it to way more oxygen. Then, even the humidity in the air alone can contaminate the surface causing it to flash rust, despite using an inhibitor in your blast water. If the inhibitor isn't enough to stop it at the iron, you can control it by using a round abrasive so you're not exposing the metal to so much oxygen.
If you're working on a larger project, you should rinse it with inhibitor as you go instead of waiting until the very end. The media sitting on the metal can leave spots and flash rust if left too long.
Some of our business owners have had luck using Ospho Rust Treatment to reverse flash rust after it has already set in.