How to Strip Powder Coating?
Powder coating is widely used across industries as protective layering on metal and other substrates because of its durability!
And because powder coating is so durable, it makes it incredibly difficult to remove. However, circumstances may arise when you need to repaint a part. In order to do that, you have to get rid of the powder coating from it first. So how do you do it?
There are multiple ways to remove powder coating for a fresh new paint job. These alternative methods can remove your old layer, being almost equally effective, but choosing the right one depends on several factors.
Let's discuss how to strip powder coating and choose the correct method for your parts.
Methods for Removing Powder Coating
Before we discuss how, let's ask why we need to remove our old coats. After all, when done right, powder coating guarantees long-term durability and function. But the catch here would be 'when done right.
Anyone can make errors during powder coating, or it has already seen a lot of years and needs to be repainted. Whatever the reason, there are three common ways to strip powder coating. They are media blasting, chemical stripper, and burn-off oven.
Although there are other alternatives, let's get to these three in detail and see how they are performed.
Media blasting is also known as sandblasting, which is one of the most common ways to remove powder coating. Ironically, media blasting is also used to prepare a surface before powder coating, ensuring a smooth and textured finish on the part.
Sandblasting is performed by using an air compressor to 'blast' abrasive material (like sand) through a nozzle at high velocities onto the powder-coated surface.
The media used in this process must have abrasive properties. Commonly used media are sand, CO2 pellets, plastic media, garnet, oxide, etc. Whatever the media, they're blasted with high pressure on the media. This process can be either automatic or mechanized as a batch process.
Remember to choose the bright abrasive media for blasting. Sand can be used to remove the toughest of powder coats, but it will leave a rough effect on the surface. Plastic or water can remove mild powder coating while leaving the surface smooth.
Suggestive of the name, this method uses hot or cold chemicals in batches to remove powder from the parts. Hot chemical trippers dissolve the coating, which can then be sprayed off, while coal chemicals are usually solvent-based products that can clean powder from any surface.
You should remember here that chemical strippers are dangerous to use when compared to media blasting and also cumbersome to dispose of properly as per environmental norms. Moreover, chemical strippers aren't ideal for a repainting or recoating job. They'll leave the surface bare.
With all these in mind, there are also a few positives of using chemical strippers. They're a cheaper alternative, leaving a uniform surface after removing old powder coating.
Burn-off ovens are thermal cleaning alternatives to strip old powder coating from a surface. The method utilizes very high temperatures to incinerate the coating. It turns into ash, which is then washed off.
The product is placed inside an oven and subjected to temperatures as high as 650° C, thereby igniting the coating and removing it effectively. However, as this method requires very high temperatures, they're only suitable for parts that are resistant to such an environment.
Burn-off falls under thermal cleaning, which also includes bake-off. Under this method, the parts are inserted inside an oven and subjected to temperatures of 300-400° C. This oven contains control mechanisms to optimize the baking rate, which is useful when you don't want your parts warped or damaged as under the burn-off method.
Other methods for stripping powder coating include thermochemical cleaning, which subjects the surface to chemical cleansers at high temperatures to remove the powder. This is an inline stripping method to remove powder from surfaces in a short span of time.
Another effective way of media blasting that has emerged in recent years is wet abrasive blasting. Wet abrasive blasting includes moistening the surface before being blasted by abrasive material. This method is quite suitable when you want to repaint or recoat the surface, as wet abrasive blasting cleans the surface thoroughly and provides consistency in finishing.
How to Select the Right Stripping Method for Powder Coating?
Now that you know all the methods of stripping away powder coating, you must ask yourself, how to choose the right one?
As we mentioned above, each stripping method is specific for an intended purpose. Here are some considerations that you need to factor in before choosing the right stripping method for powder coating:
Your purpose for removing the coating matters. If you need to repaint it, media blasting would be more suitable. Alternatively, if the coating has to be permanently removed, you may opt for chemical cleansing.
Nature of the Part
This also includes what type of material has to be stripped from the powder. The dimensions and material also play a role in selecting the right method.
Number of Items to be Stripped
Do you need to strip powder from large pieces of machinery or batch products? This will determine the stripping speed of your part or parts.
Safety is of paramount importance here. Chemical strippers pose environmental and health risks. Media blasting and thermal stripping are safer in this regard.
Additionally, you'd also have to factor in the purchasing and operational costs for stripping powder from your products.
Thus, you have four options in front of you when it comes to selecting the suitable method to strip off powder coating. Choosing the right one is a matter of finishing requirements, capital, and stripping time.
Rusty Lions offers sandblasting services that are efficient, clean, and eco-friendly for removing powder coating. We can strip away old powder coating to make your products prime for a new paint job.