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How Do You Touch Up Powder Coating?

Posted on: October 25th, 2017 by byersbushblog

Powder coating presents many advantages over traditional and equally popular coatings like liquid paint. One of these advantages is the various ways that the coating can be touched up, fine-tuned, or reworked.

Let’s face it, even the most experienced will at one time or another find defects in the final coat. How do you touch up powder coating?

Identifying Defects

identifying defects

Obviously, before any touch up can be done it is necessary to identify the defects that have to be fixed. Properly identifying defects will also give you an idea whether it can be corrected or not. If the cost of touching up will be higher than the scrap value of the product, then you have to simply toss it out.

Is the defect the result of a fabrication mistake or substrate metal flaw? If this is the case, you cannot just repaint it to correct the defect. The material has to be sent back to the fabrication before any touching up can be done. If the defect is due to the coating process, then by all means prepare the surface and recoat it.

It is important to understand that the best time to identify defects will always be prior to curing. This is because the powder can just be blown off using compressed air and reapplied later. This is of course if the defect has nothing to do with the coating process. Keep in mind that each mistake that you catch translates to savings in effort, time, and money.

 

Reasons for Touching Up

reasons for touching up

Aside from fixing defects, there are also other reasons why you should consider touching up powder coating finishes. Some of these reasons include:

  1. Beautiful Finish – one of the reasons for powder coating is to increase the visual appeal of the product. If there are defects on the finish, this would not be acceptable so you need to touch it up.
  2. Performance Requirements – some materials use powder coating as part of its functionality. For example, if the parts require corrosion resistance, then it is powder coated. However, if the finish is defective, this purpose is not met.
  3. Quality Control – professional powder coaters adhere to certain standards for the finished product. Any defect will not pass quality control so it needs to be fixed.

Touching Up Techniques

touching up techniques

How can you touch up powder coating defects effectively? There are actually a number of ways that this can be done. Here are some techniques:

  1. Liquid Paint – this relies on color matching to fix defects on the coat. It requires very little skill, not labor intensive, can be done quickly, and does not cost much. Unfortunately, the resulting coat may not be visually acceptable and not as durable as expected. This technique is ideal for decorative finishes.
  2. Re-coating – it is necessary for this technique to ensure that the surface is free from any contaminants. There will be instances wherein the surface needs to be abraded before it is touched up. This is faster and less expensive than stripping and allows for better corrosion protection. It may pose the problem of film buildup that can cause problems. When using this technique, set the powder gun to re-coat.
  3. Sanding and Buffing – if you are after a mirror like finish that can be buffed faster than paint, then this is the technique to use. But if you have some burn-through you will need to repaint these, which means requiring moderate skills. This technique is often used by the automotive industry. Make sure that you buff the finish immediately after curing because the powder coat can get extremely hard after a day.
  4. Fillers and Putties – products are used to fill the gaps and seal holes before powder coating. This eliminates the need to re-weld smaller areas and makes defects less noticeable. You do run the risk of the powder not clinging to the repaired area or the filler not being compatible with curing temperatures. Make sure that you use two-component fillers that have conductive elements to get the best result from this technique.
  5. Total Strip and Repaint – sometimes you have no choice but to start over. This is the technique that you need to do because it allows you to go back to the bare metal. Normally, this solution is ideal when there are pretreatment failures or cases of underbaking and overbaking. Flaking after curing may also require this technique. The great thing with this solution is that you can still get high quality finish for the product. Unfortunately, having to start over means additional costs and spending more time with the work.
  6. Nail Polish – this technique is not common but it can bring out positive results. This is ideal when dealing with small imperfections. Simply put a small amount of powder in clear lacquer and use it for touching up. The area will match visually with the coat but will not be as durable. To get the same level of durability, a two-component catalyzed topcoat can do the job.

There are a number of ways how to touch up powder coating. But to minimize the possibility of spending more and wasting time, let the experts do the job for you. Contact Byers Bush Powder Coating now!

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