Pretreatments
Parts Cleaning: The Basics of Bases and Acids
Small changes in the pH of a cleaning bath can make the difference in achieving effective cleaning.
Read MorePowder Coating Clinic: Avoiding Rust on Parts
Q. We apply lighter colors of powder to our ticket machines for parking lots.
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Powder Coating Clinic: Masking for Logo Design
Q. We are powder coating stainless steel water bottles for our company. For our logo, we would like to use a vinyl sticker or decal before powder coating. After the coating is applied, we want to peel the vinyl off to achieve a stainless steel logo effect, so we need some kind of temperature-resistant vinyl. Any suggestions?
Read MorePowder Coating Clinic: Discoloration of Metal-Flake in Powder
Q. We have a metal-flake silver powder color that we use regularly. If the surface is abraded with a Taber wheel—or even a pencil eraser—it darkens significantly in the abraded area. We even have this problem when our parts scrape against cardboard packaging. Our supplier suggested we switch from an unbonded leafing aluminum to a more expensive bonded product. We tried the bonded leafing aluminum, but we still have the same problem. Certain types of friction create this effect, seemingly those that perhaps have a higher coefficient of friction. Do they remove the aluminum flake from the surface? Can you explain this problem and tell us why it happens with some abrasives and not with others? What can we do to stop this?
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Powder Coating Clinic: Measuring Film Thickness before Cure
Q. How can I tell if the powder film build is thick enough before I cure the powder coating? We coat a lot of square footage and we need to control our cost. We often put on too much powder to avoid light coating. I need to know what my uncured film thickness is.
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Powder Coating Clinic: Sanding for Repair
Q. We sand aluminum die-cast parts that have minor defects in the powder coating before recoating them. The small areas of dirt, metal blemishes, fibers or similar particles are sanded using 120-grit sandpaper on an orbital sander. After recoating the parts, we often find more little specks and other defects and lines from the sanding disk in the coating. My question is, does this happen because of the sandpaper we are using, or because we sand all the way to the aluminum, exposing the surface and causing it to outgas?
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Parts Cleaning Clinic: Cleaning of Inconel
Q. What cleaning methods are recommended for finishing Inconel 718?
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Parts Cleaning Clinic: Phosphate Coating Problems
Q. We electrocoat sheet metal, iron castings (machined and non-machined) and aluminum castings (machined and non-machined surfaces) and are having problems with poor phosphating on aluminum substrates. We maintain the free acid at 0.7-1.1 points and total acid at 20-24 points, and the total fluoride at 1,500 ppm. Bath temperature is 40°C to 45°C. Any suggestions?
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Parts Cleaning Clinic: Pretreatment Equipment Suppliers
Q. I am researching manufacturers of aqueous part washers and phosphate pretreatment systems for powder coating, looking for companies that build conveyor systems, washers and treatment systems; not parts washers. The parts to be cleaned are various sizes of steel, stainless and aluminum fabrications from stampings, cut to length steel tubing, and sheet metal fabrications up to 6 feet long and 3 feet wide. What are my options?
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