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Metal Prep

Metal Etching Rust Neutralizer

item(s): 40204


POR-15 Metal Prep provides the best adhesion for POR-15 Rust Preventive Coating on any metal surface, including aluminum and shiny polished metal surfaces. Our simple process gently etches metal, creating an ideal anchor pattern for coatings such as POR-15 Rust Preventive Coating, while simultaneously leaving a zinc phosphate coating to insure chemical bonding of paint and steel. Avoid other preps that may leave harmful residues which prevent proper adhesion. After thoroughly degreasing your work piece, apply environmentally safe POR-15 Metal Prep to both neutralize any rust and etch any clean bare metal. This will allow better adhesion of POR-15 Rust Preventive Coating or any other coating. POR-15 Metal Prep is not caustic, corrosive, toxic or flammable.


  • Easy to use – one step process
  • Coats metal with zinc phosphate
  • No harmful residues
  • Insures perfect paint adhesion
  • Is reusable
  • Provides perfect base for all paints
  • Removes surface rust in minutes
  • Improves welding conductivity

POR-15 Metal Prep Technical Data Sheet

Step 2 Prep it with POR-15 Metal Prep
"We located the rustiest car we could find and performed a complete floor pan replacement. The key to the repairs is etching the new metal with Metal Prep and sealing it with POR-15 and paint. This ensures that rust will not be a problem in the future." Muscle Car Review Magazine

Interesting Facts you should know about steel and prepping it before you coat it with POR-15 Rust Preventive Coating:
In every car manufacturing facility, steel in different parts of the car body often comes from different steel mills and different production lots, and the surface texture varies with the condition of the steel mill rolls which cold roll the steel to its final thickness.
Also, surface cleanliness varies with the mills cleaning procedures, especially the procedures used to control carbon smut is actually baked onto the steel during the high temperature annealing process which follows rolling. This carbon smut is impossible to remove except by mechanical abrasion.
Rust varies with the care taken in handling (1) at the steel mill, (2) during transportation and storage, and (3) during fabrication. Steel stored for a long time with rust inhibiting oil will react to form an incomplete oxide known as oil stain. The result of all this is that ordinary steel varies widely in the manner in which it accepts coatings.
Although some commercial steel provides an excellent surface for coatings, you are just as likely to find steel which gives poor adhesion and poor rust resistance, even with good coatings. Often the same mill will produce both very good and very poor surface quality, depending upon a number of uncontrolled factors.
Nearly all the above problems can be overcome by using POR-15 Metal Prep before you coat your steel. POR-15 Metal Prep is an inexpensive insurance policy that guarantees perfect adhesion of POR-15® Rust Preventive Coating to any metallic surface every time. Whether you paint your car or your fence or your outdoor furniture, the problems are always the same, because you don't know anything about the steel you're painting or what mill it came from, and you can't learn anything by just looking at it even if you have perfect vision!

Customer Reviews

Based on 49 reviews
Michael Havis
Great Product

This stuff works very well. Applied to wheel hubs and they looked brand new when finished. Highly recommended.

Peter Gibbons
Absolutely awful product - requires you to wash it all off before applying the paint coat

I bought the whole POR-15 kit. The Degreaser, the surface prep, and the paint. Two of three of these are a poor fit to the entire job I bought them to do for one very specific reason: They require water to wash clean before paint can be applied.

Here's why that's a really bad mix for most chassis work AND has seasonal limitations:

A. Most chassis have a lot of complex details, so washing it all down multiple times is a very seasonally available action for most of the U.S.

B. Getting under a vehicle to wash all of the stuff off is a near impossibility.

C. Putting water (especially pressurized, as seen in car washes) on a rusty chassis that you're trying to treat is like cutting on a wound that you're trying to heal... any water you can't dry will sit on the chassis and rust it.

D. Some chassis have really complex layered materials, so thrusting water into them multiple times to get all of the cleaning and prep materials off is absolutely counter to what many of us are trying to accomplish.

In simplest terms, this product is a total flop for my application -- refinishing and preventing rust on a chassis. In fact, it's so counter, I now do not even see why or how this product has gained popularity.

Needless to say, I'm not happy with the POR-15 product or system. And, now realize that their marketing vastly outstrips their engineering or understanding of customer uses and needs.

John Estill

Very happy with this product

Daniel Amengual
Great Product

Great product, easy to use. Painted my boat trailer axes. After removing surface rust, I gave the axes two coats of Pro-15. Axes look new and surface is hard.

Gary Ramadei
Metal Prep

Great stuff, been using it since it was called Metal Ready. Use it in ventilated areas as it is acid. I use it on blast iron differentials, keep it wet 30 minutes, wash with water, dry, flame dry, apply POR15 black and top coat with paint


Remove loose or flaking rust, paint scale, etc. Surface to be treated should be free of grease, oil, and other foreign substances. Use of POR-15 Cleaner Degreaser is highly recommended. POR-15 Metal Prep works faster at temperatures above 70°F. Apply with brush, roller, spray, or dip rusted metal directly into solution. 

On Bare Or Rusted Metal Surfaces: Keep surface wet for 20 minutes, then rinse thoroughly with water. Remove excess from painted or chrome surfaces as quickly as possible to avoid discoloration. Surface must be bone dry prior to applying POR-15 Rust Preventive Coating. Do not store in metal containers.

* May stain Alloy surfaces. Use Alloy Prep (formerly AP-120 Metal Prep) for Alloys and soft metals like aluminum, and brass when painting with 2k Urethane Clear.