Our experts will teach you how to remove rust on metal the right way the first time. Typically, a rust remover spray from a auto parts store is not enough. It may require several hours to finish the task.
If you do nothing, then it will continue to grow and possibly become non-repairable. This article will provide information on the reasons, methods, and steps involved in completing a rust repair. Don’t miss our ridiculously long list of everything car detailing for more great articles on all of your interest.
What is rust & why does it happen
Rust is a chemical reaction between an iron atom, an oxygen atom and water. That reaction will only happen if all three of these ingredients are present at the same time. If you prevent any one of these materials from reaching the others, then the reaction will stop. Follow this link to learn more from wiki about rust.
The thing we need to clarify is that within this reaction water is the catalyst. Water molecules force iron and oxygen to combine to form iron oxide, also known as rust. It is important to understand that the reaction does not consume the water molecules.
If you do not remove “all” of the moisture, then the rust reaction will continue even under a touchup paint seal. In this case the water molecules are acting like a battery that is powering the reaction into rust. Remove the rust that you can and dry surface with heat gun to eliminate moisture.
How to remove rust from metal
How to remove rust from metal objects is usually a multi-step process. Performing all the following methods of rust removal will be necessary for deeper rust on the metal. Absolutely do not use a wire brush on car rock chip repairs. Instead learn about how to repair rock chips from our blog.
Surface rust removal
The rust reaction always begins on the outermost surface of the metal that has become exposed to water. The rust stains will always appear as an orange-like color and removing it is simple. Use a fiberglass rust remover pen, folded sandpaper, or a razor blade to scrape the rust area off the surface.
Clean the previously rusted area with isopropyl alcohol and dry the surface completely using a heat gun. To make sure the water in rubbing alcohol is all gone, heat the metal again. For larger areas of exposed metal use acid etching primer and then a single-stage car touchup paint. Otherwise, if no rust is present then skip the primer and apply only car touchup paint instead.
Flaking layers of rust
When flaky layers of rust are showing, you will need a few more tools to overcome this rust problem. You need a wire brush attachment and a power drill, a hammer and a flathead screwdriver to use as a chisel. Chisel the flakes away allowing your strikes to aim slightly into the rusty metal surface. Begin with gentle taps and increase force if needed to remove all the material that can break and come off.
To stay safe, wear a well-fitting mask and glasses to protect yourself from rust dust in the air. Hold the power drill steady wand spin the wire brush on the metal surface. Press hard into the flakes to ensure deep cutting into the rusty metal.
Cross hatch your cutting direction by rotating the drill. Use a file to smooth out high areas, as it helps to get the brush down into lower spots. Continue until the surface is almost completely a silvery color and mostly free of rust.
Rust holes
If there’s a hole, continue to press hard while spinning the wire brush along the edges to remove damaged metal. When the hole stops growing that is when you have reached good metal again. Depending on the severity of the rust, the hole may be big enough for you to access the metal from behind. We sometimes have to separate a seam to remove the rust completely.
Use a flashlight for better visibility and continue to peal apart any seems that still contain rust in the cracks. Do your best to remove as many rust particles as you can. However, it may not be possible to remove all of them from small spaces. Blow compressed air into the cracks to remove even more rust particles.
How to treat rust on car metal
Most rust treatment products like mar-hyde require that you remove as much of the surface rust as possible. These materials will control the surface environment and stop any rust reaction, resulting in a rust repair.
Use a diabetic needle to squirt your rust treatment material into all the tiny places you can’t reach. Use more material than you need so that the excess drips out. Focus on getting the rust remover to cover the entire inside surface. If you miss “any” spots from behind the metal, then it will likely just continue to rust.
Use compressed air to blow rust treatment material into cracks and along the backside of the metal. Repeat this process as many times as needed. When using more rust remover on bare metal, allow at least 30 minutes for each coat to dry. Finally, apply rust treatment material with a paint brush on any visible surface.
Do not apply more than two separate coatings to the visible exterior surfaces. Keep any peeled seams exposed and let the material dry completely for 1-2 hours. Occasionally apply mild heat to speed up the dry time.
How to fix rust on a car
At this stage you have reached the halfway point in how to fix rust on a car. The next steps are pretty straight forward, and you will need a few more materials to move forward. You may need several items for this task. These include panel bonder epoxy, body-filler, primer, sandpaper (320, 600, and 1000 grit), painters’ tape, backing paper, and spray paint.
Using panel bonder resin
Mix or use an extrusion tube to apply the resin to all the affected area. Ensure that you fill in the peeled seams and the hole. Try to fit as much resin as possible into all the exposed openings. Spread the sticky resin with a gloved finger and close the seams using plyers. Take your time and do this step correctly to ensure a proper bonding.
Rust holes with metal backing behind it
If the hole has some metal behind it, then this step will be easy. Fill the rust hole with resin and apply painters’ tape across the surface and tamp it flat and leave to dry. You will file off excess resin at the end of the drying process.
Rust holes with open space behind it
Using body filler on resin
After the resin has cured, use a file to shave the material flat to the surface. It’s ok to go slightly deeper into the dried resin because we’ll use some body filler to make the surface smooth. Clean the area, use body filler, and sand it with 320 grit dry sandpaper for a better repair finish.
Using primer & paint in a small area
Use backing paper and tape to cover the area for repainting. First, apply a thin layer of primer. Next, use 600 grit sandpaper to wet sand the surface. After that, apply thicker coat of primer. Finally, wet sand the surface again, this time using 1000 grit sandpaper and then paint and clear coat or use a spray can texture coating like we did in this example.
If there are also scratches to manage then be sure to level up your knowledge by reading our article on how to buff out scratches from a car.
