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Powder Coating Removal: How to Get the Coating Off

Posted on: February 19th, 2018 by byersbushblog

Powder Coating Removal: How to Get the Coating Off

The technology behind powder coating is straightforward and effective.  Electrostatic charge ensures that every inch of the item you are coating gets covered.  The curing process is so effective that it can be hard to remove the powder coating, should you choose to do so in the future.  Industrial paints and coatings are a challenge to remove. Powder coating removal can be even harder.  How do you remove powder coatings?  Let’s discuss a few points.

remove powder coating

Source: Pinkbike

Mechanical Solutions

Powder coatings can be removed with a sandblasting machine.  This works good for steel parts as they can withstand the erosive effect of the sandblasting.  If the parts are small enough you can perform this operation in a sandblasting booth.  For larger pieces you may need to set up a tent and use a blasting wand.  There different media that can be utilized for the blasting.  Fine grit sand is the most common, but glass beads can also be used.  You can vary the size of the media and increase the pressure until you achieve the desired results.  Either way powder coatings are hard to get off.  Plan on working at it for a while.

Chemical Solutions

Another option is to melt off the powder coating using chemicals.  Powder coatings are polymer based and like any plastic or acrylic they can be dissolved.  If you are trying to remove a powder coating from a strong substratum like steel, the power of a sandblasting machine shouldn’t damage the unit.  Softer structures like aluminum are not so forgiving.  In that case try using chemicals to dissolve the powder coating.  These are referred to as paint or epoxy strippers and can be purchased in most hardware stores.

chemical coating removal

There are some stripper products that utilize citrus acid as their base.  These are more environmentally friendly but hardly scratch the surface of powder coatings.  Powder coatings were designed and carefully developed to withstand tough environments.  It would be best to purchase the highest strength paint and epoxy stripper on the market.  Some have found the virus based strippers to be useful as a final step.  As they are not as harsh as their industrial counterparts, you can spray them in the morning then leave them out all day.

TIP: read and follow the instructions on the labels of the stripper you purchase.  The manufacturer has an in depth understanding of the chemical composition.

Removing Powder Coating from Aluminum: The Step By Step Process

First Step: Stripper Application

To begin, apply the first coating of chemical stripper.  You will need to administer multiple coats of stripper.  Pour some of the stripper into an aluminum can for easy brush dipping access.  Apply the first coat then wait for the chemical reaction to soften the top layer of powder coating.  After about 15 minutes return and apply another generous coating of paint and epoxy stripper.  After an additional 15 minutes, you can use a plastic scraper and bristled brushes to begin removing the top layer.  There are also brass scrub brushes available.  If you are concerned about damaging the original texture, avoid hard wire brushes and metal scrapers.

TIP: Use a smooth bristled brush and apply the stripper carefully to avoid splattering the chemical.

Another helpful practice is to soak the unit overnight in industrial strength carburetor cleaner. This will start the process of etching the powder coating and make the stripping easier.

Paint and epoxy strippers are powerful chemicals.  Read the safety recommendations on the label of the product carefully.  Wear your safety glasses and gloves.  Just a little bit on your skin will burn you.  If you get it in your eyes it can cause irreversible damage.  Wear long sleeves and be sure to establish good ventilation in the place you are working.

TIP: Purchase a box of disposable latex gloves and throw each pair away when you take them off.

Second Step: Stripping The Under Layers

Now that you have removed the top layers of powder coating, the hard part is done.  Soak the unit over night again in the carburetor cleaner.  Next continue administering stripper coats.  Be sure to keep the unit moist in stripper.  Do not allow it to dry out.  You will now find the powder coating very reactive.  It will bubble and blister.  As this occurs, gently scrape it off.  Some prefer not to brush or scrape at this point.  They just keep applying coats of stripper until the powder coating falls away.  It’s faster if you use a scraper and brush to remove the loosened coating.  The chemical stripper is a liquid and will find its way into abrasions in the powder coating and underneath.  These are the areas you will first notice falling away.  Bare aluminum should begin to show through after approximately four stripping coats.

TIP: Flat smooth areas are pretty easy to strip down.  The creases and crevasses are not so cooperative.  Utilizing a plastic scraping tool helps, but they tend to get worn down quickly.  Regularly take the scraper to a sanding belt and give it a new edge.

Continue this process until all the bulky parts of the powder coating have cleared off.  Now only a slight stain will be present in the texture of your aluminum.  This is where the bristled brushes come in, keep scrubbing until all the powder coating residue is gone.

Third Step: Use Carburetor Cleaner and a Wire Brush

For a car’s engine to operate correctly, the carburetor sucks air into the combustion chamber.  The cleaners they have formulated to care for this part of the engine are powerful and leave little to no residue.  This makes Carburetor Cleaner perfect for our next step.  Generally people seem to agree that Carburetor Cleaner is the most effective for removing the final stages of a powder coating.

wire brush

TIP: Some have had success using acetone as a cleaning agent, others prefer brake cleaner.  Experiment and see which method works best for you.

When it comes to this final stage in the process, exercise the caution.  You don’t want to scratch the texture of your aluminum part.  Use plastic or brass wire brushes to gently scrub the left over powder coating out.  If you plan on re-coating the unit, then don’t worry so much about scratching the surface.  It may save time to use a steel wire brush instead of brass or plastic.

Carburetor cleaners usually come in spray cans as you need to squirt it into the carburetor.  Spray the unit with the cleaner.  Brushing in gentle circles, wipe the residual off with a clean towel.  This enables you to view clearly where you have made progress and focus your cleaning efforts.  Repeat the process and you will see the aluminum gradually begin to shine.

Fourth Step: Back to Pure Aluminum

So you’ve been working at this for days now what are the results?  Pure clean aluminum.  Even though it’s a lot of effort to remove the powder coating, its well worth it when you see the final product. If the unit is brushed aluminum it will have a soft dull texture.  Polished aluminum shines.  You may need to polish the finished product.

Iron and Steel

How can one strip powder coating from iron and steel?  The process is the same as for aluminum.  Because the substrate is stronger you can use steel wire brushes and scrapers to aid in the powder coating removal.  Something to consider about steel and iron, is rust.  Once the powder coating has been removed the item will begin to rust.  Try to keep it in a dry place.  If rusting does occurs, no sweat.  You can remove the rust with a media blaster or sandblasting setup.

If your looking for a less toxic stripper for powder coating then research the citrus based strippers.  These take longer to work, but with a bit of patience you can do it.

Some have suggested using boiling hot caustic.  This is acceptable for steel and iron but not for aluminum.  The caustic will react with the aluminum, damaging the parts.  Methylene chloride is sometimes used in the aerospace industry for stripping metals.  This chemical doesn’t react with the aluminum, but it is very dangerous.  If you choose to go this route, make safety a primary consideration.

iron and steel

Strippers with a high concentration of methylene chloride work the fastest.  Smaller parts can simply be dipped into the chemical.  Stop by and inspect the parts every five to ten minutes.  When you notice the powder coating starting to separate, pull the item out.  Then you can rinse it in water mixed with tri-sodium phosphate to neutralize the stripper.  To get rid of any stripper residue left over, put the item in an oven for ten minutes or so.  This will evaporate the residual chemical.

TIP: if the item is too large, soak a cloth in the chemical and wrap the unit.

Safe Storage of Powder Coating Stripper

These toxic and potentially dangerous chemicals need to be stored in HDPE containers with a sealable top.  Use a container that is the same size as your oven.  You won’t need to dip items larger than the oven you use.  The larger items will be stripped using rags soaked in the chemical stripper.  These rags need to be stored properly as well.  If you keep them in an appropriate sealable container, they can even be reused.

It is also important to keep these chemical paint and epoxy strippers out of the reach of children.  Always wear the appropriate safety glasses and protective equipment.  Make use of thick neoprene gloves and even a face shield.

Some choose the purchase Overpack Drums.  These drums are specifically designed for storing powder coating stripping chemicals.  Overpack Drums work great for  methylene chloride based strippers.  In fact many professional powder coating and prepping shops utilize these drums for storing stripper.  The design provides a sealing lid that secures tightly and secure.  This is one of the most important aspects of a stripper storage container.  You want to keep the stripper form evaporating and prevent the odor.  The down side is that these Overpack Drums tend to be a bit expensive, but safety is worth investing in.

Often professional shops will purchase at least two of these drums.  They have one they use to store their powder coating stripper chemical.  The other one is used as a rinsing drum.  High quality drums like these used in conjunction with appropriate safety equipment is a good idea.  Safety equipment includes such things as ventilating fans, chemical gloves, and a chemical apron.

Stripping powder coating is not an easy job.  There are many different strippers for powder coating.  Couple these with sand blasting and paint removal becomes possible. Byers Bush encourages you to give stripping powder coating a try.  Of course if you need any help we are happy to assist.  Give us a call!

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