How to Care for Your Metal Sign

How to Care for Your Metal Sign

Caring for your metal sign will depend on the top coat on it. Here are a few options you'll want to understand.

1. If your sign is raw metal, unpainted steel or iron, hot rolled, cold rolled, mill scale, or even rusted:

  - The easiest trick is to spray with WD-40 and wipe with a microfiber rag. The metal is pourous and will absorb the penetrant over a period of up to 1 year. The hotter the weather, the faster it will absorb. If your sign is in direct sunlight it may also absorb more quickly. If your raw metal sign is outdoors, the WD-40 does surprisingly last quite a while and you can reapply as often as you'd like.

  - Following directions in the note above, WD-40 can also be substituted with 3-2-1 oil easily found in your local craft or home supply store. Otherwise, a quick checkout on Amazon will surely land the product right to your door within a few days. 

  - There are many oils that can be used; however, some lubricating metal penetrants have a nasty odor so if you are at the auto parts store trying to select one (there are a lot of options) just choose one within your budget, and make sure it doesn't have a strong odor. 

mill scale metal sign - raw metal - gather

2. If your sign is sign is painted or powdercoated:

  - Great news, the metal is protected for the most part, barring any imperfections like deep scratches or chips in paint or powder coat which expose bare metal. For simple cleaning applications, you'll want to wipe lightly with a microfiber rag. If there is a lot of dust, be careful to not push the rag into the metal too hard as it could scratch the paint or powder. 



3. If your painted or powdercoated sign is faded:

  Often times, if the sign fades in the sunlight, it lacks a proper UV top coat or enough time has passed (many years) where the top coat has weakened in the direct sunlight. The trick here is to scuff up the paint or powder until it is not shiny, being careful not to scuff the paint completely off in any one spot. You don't want to see bare metal, just get the shine off and give it a consistently sanded matte look. 220 grit is usually safe for this process. You can use a clear enamel spray paint that has UV protection from any big box store and give it a few coats, 15 min apart and following the manufacturers instructions on the can. 

    * Pro Tip: did you know that auto paint found at an auto parts store is usually higher quality? Check out the selection there and you can find paints that will dry harder and are made to last longer in the direct sunlight. Also available on Amazon too of course. 


4. If your sign is very rusted

   There are many ways to clean the rust off of a sign but there is one thing in particular that you should know. Rusting causes pitting, so even if you clean every last ounce of rust off of a sign, it may not clean up perfectly. This may be ok, just something to note based on your goals with the metal sign. 
    * Pro tip: if you want to make your sign look perfect again and plan to paint, you can use a heavy build-up sandable primer and sand between coats. This will fill in the pitting with some extra sanding work. 


  How to remove rust:
    Step 1. There are many products available that will remove rust from metal, and again, the product you select will depend on what your final goal is. 
    Step 2. Please consider protecting your health from the dust caused from removing the rust. It is not good to breath, and it gets in your eyes if removing a lot of it. Wear the proper face mask, eye protection, and leather gloves to protect your hands from spinning abrasive wheels. 
    Step 3. What tool to use. An orbital sander is better than doing it by hand, but slower than a 4.5" angle grinder. Depending on the tool you are using, you'll select the abrasives that fit that tool based on the selection available. 
    Step 4. Abrasives. Sandpaper will work, albeit slowly. The faster the sandpaper can rub across the rust the faster the rust will come off. Also, the sandpaper will wear down quickly, but not as quickly as a paint removal abrasive, which looks like a scotch brite pad dipped in purple paint. The paint removal bristles are soft and are great for removing paint and rust on metal but they wear out the quickest. If you have an angle grinder, the best way to remove rust is with a wire wheel. There are two wire types and many styles of wire configurations available that could be its own blog post: however, I will cover the most basic here. Get yourself a cup brush (fine wire) for flat spots, and a straight wire wheel for corners or harder to reach areas. This will make the quickest work and the wire wheel will last longer than the sandpaper or paint removal tool. Once the rust is removed, you can add an oil coating or paint the sign again. 

5. Painting a metal sign

  Painting any metal object you will want to follow these beginner steps. Metal should be free and clear of any dirt, oil, residue, or lint fragments before painting. Protect your hands with some disposable chemical resistant gloves and get a bottle or can of acetone (mineral spirits or paint thinner will also work). With a microfiber rag, spray or pour the chemical onto the rag and clean the raw metal. Even microfiber rags may leave a little lint on the sign, so it is ideal to burn the lint off with a small propane torch. Using a fresh (clean) set of disposable gloves to handle the clean sign, make sure it is completely dry before spraying a self-etching primer as a base. Take the time to read and follow the manufacturers instructions on the can for best results. This will tell you how far away the can should be when you spray and how long to wait between coats. 
  Apply your top coat to the fully cured prime coat. Emphasis on letting the prime coat fully cure. The top coat will seal the base coat and add additional protection to the sign as well as the color of your choice. Ensure the paint you choose is compatible with the base coat used as some top coats are known to actually disolve base coats. If you have questions, someone in the paint section will surely be able to help. 

Was this post helpful? What other questions came up while reading this? I'd love to answer them for you.


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