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Step by Step Tutorial in Preparing Powder Coating Metal

Posted on: June 11th, 2018 by byersbushblog No Comments

In case you did not know it, there are some specific steps you need to do to prepare metal for powder coating. Why is it important? Well, if you do the steps properly, you can be sure that about 99% of potential problems can be eliminated. So how do you do it?

How to Prep Powder Coating Metal

Step 1:  Disassembly

It is important to point out that in coating processes, disassembly may not always be necessary. This step would depend on the actual material that you will be coating. For products that have rubber, plastic, wiring, gaskets, or anything similar, you need to disassemble it so that you can removed these parts that can be damaged by the baking process. The same goes for bearings and magnets even if these are made from metal. To ensure that you can bring everything back together, take pictures before the disassembly. Take this opportunity to replace old and worn out parts as well.

Step 2: Cleaning

This step is intended to remove all impurities like oil, dirt, grime, and grease from all of the parts that will go through powder coating. It does not matter if you will be using powder coating kits or a production type process, removing these impurities will help ensure a better quality finish. Rust and paint residue can be taken care of later, at this point all you want to achieve is to be able to sit the material on a white cloth without creating stain.

What can you use? Normally a general degreaser works fine. Take note that the type of cleaner you will be using will depend on the material you will be coating. This means that there are different cleaning products for steel, aluminum, and other types of materials. Scrub brushes seem to work best in combination with an electric pressure washer when dealing with larger materials.

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Step 3: Stripping

Once the material has been thoroughly cleaned and dried, you can now take time to remove the previous coating. It does not matter if it was powder coated, painted, or whatever finishing it had before, it has to go. This can take time depending on the amount of coating there is to work with. Stripping can prove to be a time saver when dealing with previous coatings.

Step 4: Outgassing

Powder coating metal processes require you to do outgassing. Why? This is because some materials like cast aluminum or cast iron have the tendency to absorb oils. This means that these oils, unless outgassed, can go to the surface during the coating process and ruin the finish. Now, it is vital to understand that not all materials needs to be outgassed so you can consider this as an optional process.

When working with material that has been in a greasy environment for a long time, make sure to outgas it. This is a pretty simple procedure, just pre-bake the material in the oven at a temperature that is higher than what you would need during curing. You also have to leave it in the oven at a longer time. It is normal to see smoke during outgassing, this is from the oil that is burning up. Ideal temperature would be around 440 degrees for about 30 minutes. The bigger the material, the higher the temperature and the longer the time you need to outgas.

Step 5: Sandblasting or Phosphate Coating or Both

You are now ready to sandblast away. What will this do? Basically, it will continue to clean the material up to the point where only the bare metal is left. Sandblasting will also create a texture to allow the powder to stick to it better. You need a clean media to go through the material completely to achieve the best result. However, it should be pointed out that some materials are not made for sandblasting like cylinder bores or brake calipers for example. Make sure that the media is always clean because any dirt or oil will destroy the finish on the material. After you have completed sandblasting you can never touch the material with your bare hands again.

Step 6: Post-Sandblast Cleaning

The material is now cleared of all contaminates, but, there will still be sandblasting dust all over it.  You need to put a pair of clean gloves and remove the material from the cabinet. Use the air compressor to spray off the dust. It is important to use clean air by installing a moisture removal filter on the air line. This is to prevent any contamination on the already cleaned part. Scrub the part completely using a stiff bristled brush and then subject it to the air compressor again. Put denatured alcohol on a clean towel and gently move along the surface of the material. Using a lint-free cloth is also desired. Finishing off with the air compressor removes any lint residue and allows the denatured alcohol to completely evaporate.

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Step 7: Masking

This process depends on the part that will be powder coated, which means this can be optional. If you do need to mask some parts, make sure that you are still wearing clean gloves. You do not want any sweat or oil from your fingers to be transferred to the material. Make sure that the workbench is clean as well.

Step 8: Hanging

After you have gone through all the steps, the last thing to do is to hang the material. There are a variety of hooks that you can use depending on the size of the material to be powder coated. Naturally, bigger materials require bigger and stronger hooks. You do not want your material to touch anything else before it is powder coated, especially the floor. When you are using a grounded rack, ensure that the hook is clean bare metal so it can effectively conduct the ground to the material.

If you follow these steps closely and properly, there is no doubt that you will be able to successfully achieve the right powder coating finish. Keep in mind that preparation is about 90% of the job, so if done properly, there is less likelihood for mistakes.

However, if you find yourself unprepared, need help, or want expert powder coating metal service, simply call Byers Bush Powder Coating Inc. today.

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