July 19, 2022
On occasion, you’ll need to either reapply your chosen ZRC solution or apply it for the first time to a metal structure that has already been exposed to the elements. Both of these instances require the surface to be properly prepared first.
Knowing this is only the first step, though. Here at ZRC, we take pride in not only selling zinc-rich coatings but also educating our community and industry. That's why we're the go-to experts in the industry for all things relating to preventing rust. We’re regularly asked questions about this process from people just like you. Let’s dig deeper into the questions our team is commonly asked.
How to Properly Prep the Surface Before Applying ZRC
Proper preparation is key in many areas of life. You wouldn’t face a hurricane without pulling in your deck furniture and stocking up on candles. You wouldn’t go for a run without drinking water and stretching your muscles. You wouldn’t dream of cooking Thanksgiving dinner without washing your hands and de-thawing the turkey first.
Just like these and countless other examples, you want to take the necessary preparations before you get started applying a new coat of ZRC. A few of the most common questions we hear quite often include:
Why Would I Need to Prep the Surface to Apply ZRC?
When we say applying ZRC keeps your metal structure rust-free and in good condition for longer, we mean it. That being said, it doesn’t last forever. If you applied ZRC 15 or 20 years ago and begin to see red rust, you’ll need to clean it up and apply it again. Perhaps in your case, you have new steel put into the field that has not yet had ZRC applied to it yet. A third occasion where you would need to prep the surface would be if the steel has been in place for years that was only painted with regular paint.
In short, wherever you want to protect metal from further corrosion, especially in a corrosive environment, you’re going to want to properly prepare the surface and then apply ZRC.
Does My Specific Substrate Need to be Prepped First?
Yes! You may think this would require a long answer filled with specifics, but it actually does not. No matter what type of surface you're painting, it has to be prepared first.
Is This Going to Take a Long Time?
The answer to this really depends on your unique situation. Properly preparing your surface can range anywhere from a very minimal amount of time and effort to a fairly substantial degree of effort. It all depends what on the initial substrate/metal is like. If it is clean, cold rolled steel, you probably just need to make sure there’s no grease or oil. If it’s badly rusted, however, you will need to get rid of all the loosely adherent rust and get down to bare metal. You possibly even need to sandblast it.
You need to do the procedure, get the surface dry, then apply the ZRC as soon as possible. Keep in mind that applying ZRC to wet or damp surfaces will result in poor adhesion and ultimate coating failure.
Water jetting requires drying before putting on ZRC. If you’re in a time crunch, sandblasting instead of water jetting means you don’t need to wait for it to dry. The very last step is to wipe it down with a mineral spirits solvent. It can all be done rather quickly. For additional information on specs, read this document.
What Is My Goal in Doing This?
You want the surface metal you’re going to apply the ZRC solution to to be:
CLEAN
DRY
BARE
These are the most important things! All loose salt corrosion needs to be removed. The reason you need to take all of the salts off is to get it as clean as possible. This will allow the zinc to be in contact with the metal, allowing it to bond.
Why Is Proper Surface Preparation so Important?
This is real galvanizing, not paint - it is just applied like paint. The fewer impurities on the surface, the more effective the ZRC product will be. Anything in between is going to act as a barrier and reduce the effectiveness of your application.
What Needs to be Removed?
When you’re preparing the surface of the metal, you want to be sure you remove:
- Paint chips
- Oil
- Grease
- Dirt
- Mildew
This list is a starting point. It is important to note that if it has been previously painted, all of it needs to be removed, not just chips. If you have rust that is tightly-adherent and unable to be removed, ZRC will work when applied over that because it is electrically conductive.
Is There Any Difference Between Prepping the Surface for ZRC and Regular Paint?
The big difference is with regular paint you don’t need to get down to bare metal. You can remove what’s loose and paint over the other paint with new paint. This is not the case for ZRC products. ZRC needs to be applied to bare metal. Anything else is going to be a barrier, even paint that still looks okay.
Anything other than the bare metal itself is in the way of the cohesion of the zinc-rich solution. Remember, you’re getting it galvanized and not just painted. This is a lot better rust protection!
What is Used to do the Cleaning?
You may wonder if just high-powered water will do the trick or if chemicals and soap are needed too. You don’t need to treat the steel with detergent of any kind. Do not use a rust converter, cleaning solutions, etc. These stay as a barrier and may leave a residue.
This process is incompatible with ZRC and therefore we do not recommend this. It could leave a barrier that stops the galvanizing. We suggest using a solvent wipe with paint thinner or power tool cleaning.
You can always check with the Association for Materials Protection and Performance for exact specifications.
Do You Need to Remove Zinc on Previously-Galvanized Sheet Steel?
In this case, no. This is a form of galvanizing on sheet metal and so you don't. It still has electrical conductivity, and will not act as a barrier that reduces the effectiveness of ZRC products
Contact the Industry Experts at ZRC
While zinc corrodes differently in different environments, blasting it clean and then applying a new coat means your application will always last longer. This is because you’ve increased the surface area by making little “hills” so to speak. The zinc is in contact with all of that extra space. More zinc means more protection, and that’s precisely what you’re looking for.
With any additional questions or concerns, we’re here for you. Reach out to our team of experts and let us point you in the right direction of your best ZRC solution, how to prepare your specific surface metal, and more.
