Buyers Guide: When to Use Rust Encapsulator VS. Rust Converter

Our tech team answers a lot of technical calls and emails each day and there are a lot of common questions asked and advice given. Many of them are about when and where to use our different coatings and paints. Rust products might be the most confusing as far as when to use them and which one is correct for your rust situation. I decided to put together this quick article to help you decide when you should use Rust Encapsulator vs. Rust Converter.


Rust Encapsulator

Rust Encapsulator is one of our oldest and most well known products we sell. We’ve been an innovator in rust treatments and this product has stood the test of time. Encapsulator is probably the safest and most universal of our rust products as it doesn’t much care what it is applied over. Below are some examples of situations where Rust Encapsulator is ideal and where another product may be better.

Ideal Encapsulator Uses

1. Surface Rust- Encapsulator will easily go over areas of surface rust and stop the rust from spreading. One medium coat usually covers light surface rust.

Photo Sep 18, 2 38 50 PM

2. Medium Rust- This is rust that is more than just surface or flash rust, it may have started to lightly pit the metal, but hasn’t started to affect the rigidity of the metal. Start by wire wheeling or mechanically removing any loose rust and apply 2-3 medium coats to get complete penetration into the rust.

3. Bare Metal- Rust Encapsulator can be used over bare metal, but I wouldn’t suggest it over an epoxy or etch primer if you ONLY have bare metal to deal with. It can be used to quickly seal bare metal in a pinch to avoid flash rusting as well.

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4. Mixed Surfaces- Rust Encapsulator is the best rust product to apply over surfaces that might vary in grades of rust, have bare metal or old paint present. If you have an area that you cleaned to bare metal or repaired and there’s still rust around that area, I’d suggest Rust Encapsulator.

Poor Uses

While Rust Encapsulator can be applied to almost any surface, it isn’t always the best option. Below are instances where we’d suggest a different product for the best results.

1. Over rubberized undercoating or heavy duty anti-rust– Undercoating and Anti-Rust are great products for undercarriage, or hidden areas on a vehicle but using Rust Encapsulator over them is unnecessary and isn’t using the product to it’s full potential. I absolutely prefer to use it as a base under rubberized undercoating for piece of mind.

2. In hidden, boxed, or hard to reach areas- Rust Encapsulator needs some basic prep before application (wire brush loose rust and degrease with PRE). It also needs complete coverage to properly stop the rust and it can be tough to get it to cover properly on an area that hasn’t been prepared completely. For hidden, boxed, and hard to reach areas we suggest our Internal Frame Coating.

Rust Converter

Rust Converter is a coating that will convert heavy rusted areas into a protective polymeric coating with little prep. This product works well when used as directed, but doesn’t have room for error when it comes to using it on the incorrect surfaces. Rust Converter NEEDS 100% rust present in order for it to work correctly and to fully cure. The surface does need to be top coated after cured. For the best protection we suggest to apply Rust Encapsulator over the Converter and then top coat.

Ideal Uses

-Medium Rust- Areas that are completely covered in substantial rust are ok to use Rust Converter on as long as it isn’t mixed with bare metal or other coatings around it.


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-Heavy, Flaky Rust- Rust Converter works best on rust that is HEAVY. This would be scaly rust that has begun pitting the surface and has covered all of the metal. We still suggest to knock off (wire brush/wheel) the loose, flaking rust before applying the product. The goal is for the entire surface that is rust to turn a purplish-black once the converter has finished curing. It may take 2-4 coats to fully convert a surface.

Poor Uses

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-Bare Metal- DO NOT EVER apply Rust Converter over bare metal. This product needs 100% rust present for it to work. In fact virgin, clean metal could actually flash rust if Rust Converter is applied and left on it.

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-Mixed Surfaces- Rust Converter needs 100% rust present in order for it to fully cure. This means it won’t work completely on areas that are a mix of rust and bare metal, or a mix of original paint and rust. If you’re trying to treat small rust spots that have paint surrounding them (that we assume you don’t want to damage) you can use Fast Etch to saturate the area and get into those small rust spots. Then touch up with paint as needed.

-Painted or coated surfaces- This product won’t work on bare metal areas to protect or prevent from rust. If applied to areas that are painted or used to coat for prevention the Rust Converter won’t fully cure and the surface will stay sticky.

If you follow these quick guidelines you can quickly determine if you need Rust Encapsulator or Rust Converter. Feel free to drop us a comment if you’d like to see a buyers guide for any other product.


90 thoughts on Buyers Guide: When to Use Rust Encapsulator VS. Rust Converter

  • I hammered off what I think is paint over undercoating on my 15 passenger 2000 Dodge Van. It was on the frame and body. It flaked right off heavy flakes when hammered leaving a rusty surface. I also wire brushed it. I have a little frame extension rusted through in the far front and a little rust though of the floor by the rear wheels. I want to stop the rust. I drive on salty winter roads. I do have a HVLP spray gun/compressor. Also, what about brushing on bed liner after treating the rust? What would you recommend?

  • Hi We would definitely suggest cutting out and welding in new metal in the areas that are actually rotted out and missing metal. For the other areas you can wire brush like you mentioned and hit it with our Rust Encapsulator and then follow it up with our Chassis Black or a bed liner like you mentioned for durability.

  • How does your “internal frame coating” and “anti-rust in Amber” compare for treating enclosed box sections in a 35 year old car?

  • When I have cleaned entire body down to bare steel and all rust is gone, what should I put on to protect from flash rust. Is ‘after blast” acceptable?

  • I have a set of wheels that are about 80 years old, manufactured in England and used there until about 1972 when the car was shipped to USA. Wheels are wire spoked bolt-on with rims like a bicycle rim – edges are folded over (where the tire bead seats). This creates an inaccessible pocket around the circumferance of the rim. I hear loose rust flakes (possibly metal flakes from the vent hole that was drilled at manufacturing) within the voids. I have injected Evapo-Rust “rust remover” into the void of each wheel. Evapo-Rust “removes rust to bare metal” and “a rust eliminator” is their claim. I have never been sure if this is a “remover”, “encapsulator” or “converter”. What can you tell me about what I have done and what I should do to prevent further rusting of the wheel rims? Thanks.

  • I have a replacement windshield frame for my ’69 Blazer. The inside of the frame is showing signs of rusting on the bare metal.
    I cant see a good way to get down into the frame to brush on anything to deal with the rust short of pouring something in and sloshing it around. Any suggestions and help are greatly appreciated.


  • Very informative information about the various types of rust as well as products that work the best.
    Thanks for this

  • Two questions.I have some pitted area around the back glass of my car. Some area are probably half way through the metal. What is the best thing to do to stop it? #2. I have some rust hole in the quarter panel. I was wanting to know if I crimp the panel and use panel bonding glue to attach the new metal. Then cover it with fiberglass and body filler. later down the road would it crack? Thanks

  • The only correct way to repair those areas is to cut the metal out and replace it. Panel adhesive is good to use if you prepare the panel correctly. We’d suggest using good primer and body filler over fiberglass. A good repair will outlast the rest of the car.

  • Hi Robert, you should be able to change your page view in the print preview feature when printing the page out. Hope that helps.

  • Our internal frame coating works well for etching and sealing the metal, leaving a phosphoric coating. The Anti-Rust works best in areas that are already fairly clean. It does seal out moisture and will slow down pre-existing rust. I like to use the internal frame coating first to stop the rust and then the Anti-Rust as an extra barrier.

  • The methods you have used is about the best you can do, that is a tough one without exposing the rust fully it is hard to completely remove it since it is so hidden.

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