How to Remove Powder Coating - A Complete Guide (with video)
Anyone who has had to strip a powder coated object knows how stubborn powder coating is In fact the durability of powder coating is one of its greatest pros (more on the pros and cons of powder coating here). You may need to strip powder coating to refinish a part or to repaint a product either way being able to effectively remove powder coating can help you reduce time preparing the products surface for the next step that you will perform. This guide will cover the methods you can use to remove powder coating, the benefits and drawbacks of each type of method, what is required for each method of removing powdering coating, and more.
First Method to Remove Powder Coating Chemical Strippers
The first option you have when it comes to removing powder coating is using a chemical stripper. There are a variety of chemical strippers available that are designed to remove powder coating from a products surface. Different chemical strippers for powder coating are meant for different applications. If you are in a high production setting where you will routinely need to strip a lot of powder coating, for example if you are a repaint job shop for a 64 chevrolet, you may use chemical strippers in a dip tank where a powder coated part is immersed and the chemical removes the powder coat. Or if you will strip powder coating off a part only rarely you may consider a brush on chemical stripper. Either way this company offers chemical strippers for both dip tank uses or brush on.
Pros of Using Chemical Strippers for Powder Coating
Chemical strippers will remove all the powder coating from a surface which means you will be left with a completely uniform surface after the coating is removed. Other methods of removing powder coating can yield slight differences in the extent of how the powder has been removed (for example in a sandblast cabinet). Additionally chemical strippers are well suited for small occasional use or for large products as well. Chemical strippers and the equipment needed are also relatively cheap.
Cons of Using Chemical Strippers for Removing Powder Coating
Chemical strippers can be dangerous to work with especially compared to options like a sandblast cabinet where all the removal of powder coating is isolated by the blast cabinet. Additionally, chemical strippers can have a lot of strict environmental disposal requirements. Finally chemical strippers typically do not leave a profile to apply a new coating, this may not be drawback depending on the reason you are stripping powder coating from a products surface. Profiles of a blasted surface are often important if you plan on applying a paint to the product after you have removed the existing powder coating.
What is Required to use Chemical Strippers
Chemical strippers can require different equipment depending on how you will want to evaluate the project. For example, for a small spot stripping project you may just need a basic bottle to apply the material but with a setup for removing powder coating from large products you may require a full dip tank along with a system to properly dispose of the strippers after they have been used a while.
Second Method to Remove Powder Coating - Heat (Thermal)
If the thought of dealing with chemicals including the risks and headaches associated with chemicals is not appealing, you can consider using heat to remove powder coating. Using heat to remove powder coating can be accomplished through a bake off, burn off, or fluidized bed system. Each system whether its bake off, burn off, or fluidized beds will utilize heat but at different temperatures and can remove powder coating faster or slower depending on which system is chosen. In a bake off system the temperatures achieived will typically be 640 - 750 degree farenheit and parts will take 3 - 6 hours to become clean. The burnt off powder coating then has to be washed away in order to ensure it doesnt stick to the surface. In a burn off system temperatures can reach 1000 - 1200 degrees farenheit and in a matter of minutes have all the powder coating removed from the products surface. This solution is typically used for high production facilities due to its ability to rapidly remove powder coating. A final solution for removing powder coating with heat is a fluidized bed stripping system where a type of abrasive media is heated and then rubs against the surface of a product which strips the surface of any powder. This system operates at around 800 degrees farenheit.
Pros of Removing powder coating with heat
Using a heat system to remove powder coating can offer a fast and efficient way to remove powder coating and reduce potential environmental disposal issues that are a part of using chemical strippers. Additionally using heat can be one of the fastest ways to remove significant volumes of powder coating.
Cons of Removing Powder Coating with Heat
A few main drawbacks of removing powder coating with heat include the cost of equipment which can be thousands of dollars. Additionally ,you will have to have the ability to supply enough electricity or natural gas to provide the energy the oven will need to get hot enough to remove powder coating. Depending on your location finding sufficient gas volume to create high temperatures in an oven can be challenging. An additional drawbacks is you will still typically need some sort of wash phase after removing the powder coating to remove any burnt off powder prior to moving on to the next stage in your process. Finally, like chemical stripping to remove powder coating, their will not be a profile left on the products surface when using heat and you may alter the shape of the underlying part due to the high temperatures that are needed to burn off powder coating.
Third Method to Remove Powder Coating Abrasive Blasting
Another option that is available to remove powder coating is abrasive blasting. Whether it be abrasive blasting in a sandblast room or using a sandblast cabinet, abrasive blasting will involve using an abrasive media propelled at high speeds at a products surface which will strip the powder from the products surface. If you plan on using a full room because you will be removing powder coating from large equipment or something similar that will not fit in a blast cabinet, you will typically need to consider a blast room that can use aggressive blast medias like aluminum oxide or steel grit. However it will depend on how thick of a powder coating layer you will be removing as you may be able to use lighter medias like glass bead, for best results it can be best to have a sample test done on a small piece of product that represents what you will be routinely blasting in your sandblast room. While this article will not cover abrasive blast rooms further, you can review this guide for more information on blast rooms. If your parts you will be removing powder coating from are not that large, you can consider a sandblast cabinet instead of a blast room. For most powder coatings you will need a pressure sandblast cabinet rather than a suction sandblast cabinet because the pressure will help to remove stubborn coatings (like powder coatings) more on pressure vs suction sandblast cabinets here. You will typically also need an aggressive media like aluminum oxide or steel grit.
The Pros of Using Abrasive Blasting to Remove Powder Coating
There are a lot of potential benefits associated with using abrasive blasting to remove powder coating. First is that it is well suited for small parts up to large batch work (though not typically for production line use). A second pro to abrasive blasting for powder coating removal is it can potentially be a portable option. While we primarily mentioned a blast room or blast cabinet, you can also use a standard portable sandblast pot which would provide the possibility (depending on the thickness of powder coating applied to a product) to remove powder coating in the field. A final positive to abrasive blasting for removal of powder coating is that it will leave a profile on the surface which can eliminate the need for this step if you plan on applying a coating that requires a profile on the surface of your part.
The Cons of Using Abrasive Blasting to Remove Powder Coating
While there are a lot of good reasons to consider abrasive blasting to remove powder it also has its challenges. First, compared to the heat and chemical method it will not be as a fast of a method typically which means it may not be well suited for high production removal of powder coating. Second, it can get expensive, especially if a blast room is the idea being considered. A third drawback is that you do need a fair amount of compressed air which can be problematic depending on your situation. More on compressed air and sandblasting here.
Fourth Method for Removing Powder Coating LaserWhile it may seem like science fiction, there is actually lasers that have been designed to remove coatings from a product surface. There are a variety of potential coating removal applications and prior to considering a solution like this you want to ensure it will work on the thickness of powder coating you plan on removing as it can be a large investment to purchase a laser to remove coatings.
Pros of Using a Laser to Remove Powder Coating
A laser for powder coating removal offers the ability to remove powder from a small area up to a large surface. The laser doesn't alter the substrate at all and is a safe option without any environmental considerations that you have to evaluate. It will also not alter the surface of the product as it doesn't heat the product surface in the process of removing the powder coating.
Cons of Using a Laser to Remove Powder Coating
The equipment can be quite expensive to purchase making it prohibitive for a majority of people looking to remove powder coating. A laser doesn't profile the surface after removing the powder which can be a drawback or not depending on the application.
Ultimately removing powder coating can be a lot of work. By considering how often you plan on removing powder coating, the volume of powder coating removal you will do, and the options available discussed above you can decide on the best option for you. For most considering low volume use of removing powder coating on smaller products generally a sandblast cabinet or chemical stripping agent will be a good solution. For batch work a bake off oven, blast room, or chemical stripping tank may make sense. For high volume burn off ovens or fluidized beds may be the right choice. Finally a laser may also work for batch work especially where you do not want to alter the substrate at all in the process of removal of the powder coating.