Why We Recommend Powder Coating
The key objective of any good manufacturing industry is to deliver a high-quality product with a long life. That is why we at Coiling Technologies, Inc. recommend the powder coating of our springs. Powder coating is an important factor in achieving a high-quality, durable finish, allowing for maximum production, and improved efficiency of your spring.
Advantages of Powder Coating
- Protective and Decorative finish
- Limitless range of colors and textures available which enhance the look and feel of the spring
- The ability to apply much thicker coatings than liquid solutions and they produce almost no volatile organic compounds (VOC)
- Improves performance properties
Applying Powder Coating
Our manufacturing equipment is outfitted with a two-staged washer, which applies an iron phosphate base coat then rinse cycle to all coated items. Any piece within a size-range of 36″ H x 24″ W x 60″ L can be coated. Our adjustable speed conveyor has 175 hangers on 16 inch centers, and the two-stage 410+ degree oven can handle both the drying and curing cycle.
Contact us today to find out if a powder coating is right for your project. For more information and tips on powder coating, visit our blog post!
Powder Coating Springs FAQs
Why powder coat a spring?
Carbon and alloy steel springs corrode, and corrosion on a spring is not a cosmetic matter. A pit on a highly stressed coil concentrates stress and gives a fatigue crack somewhere to start, so surface protection is a service life issue. Powder coating delivers a protective and decorative finish in one operation, and Coiling Technologies recommends it as part of achieving a high-quality, durable finish and improved efficiency from your spring. Stainless, nickel and titanium springs generally do not need it, since their corrosion resistance already sits in the alloy chemistry.
Why choose powder coating over liquid paint?
Three practical reasons. Powder applies in much thicker films than liquid solutions, which matters on a spring where the coating has to survive coil-to-coil contact and handling. Powder produces almost no volatile organic compounds, so there is no solvent flash-off to manage. And the range of colors and textures is effectively limitless, which makes powder useful for part identification as well as protection when several similar springs feed the same assembly. Liquid paint still has a place on parts too large or too heat-sensitive for an oven cure, though few springs fall into that category.
How does the powder coating line run?
Coating equipment is outfitted with a two-stage washer that applies an iron phosphate base coat followed by a rinse cycle to every coated item. The phosphate conversion layer is what the powder mechanically keys into, and skipping pretreatment is the usual reason a coating fails early in the field. Parts hang from an adjustable speed conveyor carrying 175 hangers on 16 inch centers, then pass through a two-stage oven rated above 410 degrees that handles both the drying and the curing cycle. Conveyor speed is adjustable, so dwell time can be matched to part mass.
What size springs can be powder coated?
Any piece within a range of 36 inches high by 24 inches wide by 60 inches long can be coated. That is a working limit worth checking early if you are specifying a large compression spring, since cold coiling capacity reaches 80 inches in length, longer than the coating window. A spring that exceeds the coating envelope is still manufacturable, it simply needs a different corrosion strategy or a conversation about handling. Send overall dimensions along with the coating requirement at quote time so this gets settled before the part is coiled.
Does the cure temperature affect my spring's temper?
Cure temperature is a real design input rather than a process detail. The oven runs above 410 degrees for both drying and curing, and any thermal exposure after a spring has been stress relieved or aged has to sit below the temperature that would change its condition. For most carbon steel and stainless spring material a cure in that range stays well under the tempering temperature and nothing shifts. For a spring aged at a low temperature, or one with tight free length and rate tolerances, the cure should be checked against the heat treat schedule. Heat treating and coating both run in house, so that check happens under one quality system.
Does powder coating risk hydrogen embrittlement the way plating does?
No, and the distinction is worth keeping straight. Hydrogen embrittlement is a plating problem. Electroplating and acid pickling charge atomic hydrogen into high-strength steel, and on a spring at high hardness that hydrogen can cause delayed cracking under sustained load, which is why plated springs typically require a post-plate bake. Powder coating involves no plating bath and no cathodic hydrogen generation. The iron phosphate stage is a conversion coating rather than an electrolytic process, and the cure is a dry thermal cycle. If your print currently calls for a plated finish, powder coating removes that failure mode.
How do I handle surfaces that must stay uncoated?
Identify them on the drawing. Coating thickness sits on top of the wire, so a ground end face that has to seat flat, a hook or loop that must fit a mating pin, or a coil surface with a controlled clearance will all measure differently once coated. Film build also tends to run heavier on outside curvature and lighter in tight inside radii, so a closely wound coil does not receive perfectly uniform thickness. Call out which surfaces need to stay bare, and give a thickness range rather than a single number on the surfaces that are coated.
