Powder Particle Size
What screen sizes should we consider for determining the percentage of fines, and median and coarse material present in our powder?
Q. We are currently using an epoxy powder and are considering purchasing powder sieves to determine what percentage of fines, and median and coarse material is present in our powder. We have had a company quote the shaker and the screens, but are unsure what size the screens should be. Are 10-, 35- and 55-micron screens sufficient, or do we need to consider other sizes? –M.C.
A. You will have difficulty getting a detailed particle size analysis using a series of screens, as the particles will vary widely from top to bottom. You will have powder ranging from as small as 5 micron to as large as 120 micron. The percentage of small particles will likely be very small, and you may have difficulty getting them to work through the screen.
You could get a laser particle size analysis from the supplier to see the actual full range by percentage, or you could have an independent source do the analysis for you. The resulting graph will tell you far more than a series of screens. However, I understand that owning a machine for your own regular use is not practical.
If you proceed with the screens, you should be looking primarily at the fines, particles below 20 micron and particles below 10 micron. You may also want to see how much coarse powder you have, so something around 60 micron would be useful to determine the material larger than that size. I would have 10-, 20- and 60-micron screens to separate the coarse and fine particles. If you want one additional size in the mix to better determine the mean, I would go with a 35-micron screen.
How can you calculate the cost of powder coating a component if you only know its surface area? Powder coating expert Rodger Talbert has the answer.
Powder coating is one of the most durable finishes that can be applied to industrial manufactured products, and offers excellent corrosion protection and is very safe because of its lack of volatile organic compounds.
Question: I’ve been told that a powder coated part cannot be “touched-up.” I have some patio furniture that I had powder coated and the powder coating shop that did the work for me stripped the threads in holes used to rack the part.