Sometimes, making a custom metal basket perfect for your parts washing or finishing application takes more than just a well-chosen basket metal and sound design. In some cases, parts and even baskets may need the extra protection that a coating of another material can provide.
“What are the different coatings that can be applied to custom baskets? What are they useful for? Which one is best for my parts washing or finishing application?” These are the questions that many clients have when they come to Marlin Steel for custom baskets to hold their expensive parts through a specialized wash or finish process.
Coating Types
There are countless different types of coatings that can be applied to a custom metal form. Each year, companies work to create new coating types and even modify their application processes. In the interest of brevity, only a few common coating examples will be covered here.
Polyester TGIC Powder Coat
Polyester TGIC (triglycidyl isocyanurate) powder coats are, according to linetech.com, “the most used of all powder coatings in the U.S. market.” It’s easy to see why. Among powder coatings, polyester TGIC possesses a high pencil hardness (2h-3H), excellent resistance to marring, chipping, and UV radiation, as well as an impressive resistance to salt spray exposure (roughly 33% higher than Urethane powder coat’s resistance).
This coating is useful for protecting baskets from exposure to a number of harsh chemicals, so long as the process’ temperature doesn’t exceed 300 °F.
Epoxy High Solid Coat
With an even higher pencil hardness than polyester TGIC (3H-5H) and excellent stain, mar, chip, humidity, and solvent resistance, epoxy coatings are tough protection for a custom wire form basket. This coating is ideal for reinforcing a basket and improving its useful life.
However, epoxy coatings are not ideal for outdoor applications, as they have a poor UV resistance factor compared to other coating materials.
Plastisol (PVC)
As a coating material, Plastisol is pretty flexible, with properties that change somewhat based on the plasticizer and the process used to apply it.
For example, dipping processes generally produce a thick, soft layer of PVC over the material being dipped. Dipped Plastisol is not ideal for fine wire mesh, as the dipping process tends to leave messy webbing on thin wires that needs to be manually cleaned up. However, the semisoft nature of the dipped coating makes it great for baskets meant to hold parts that absolutely cannot be scratched.
Plastisol applied using the fluid bed process, on the other hand, tends to be thinner, making it better for wire basket applications, but also reducing its value as a cushion for delicate parts.
Beyond supplying extra padding for a wire form, Plastisol provides excellent chemical resistance, particularly when applied via the fluidized bed process, which provides a basket with a complete, even coating of material.
Fluoropolymer Coatings (AKA Teflon)
Many consumers are familiar with the product name of Teflon, primarily as a non-stick coating for cookware products. This brand name coating applies to a small family of fluoropolymer coatings:
- Polytetraflouroethylene (PTFE)
- Fluorinated ethylene propylene (FEP)
- Perfluoroalkoxy (PFA)
- Ehthylene-tetrafluoroethylene (ETFE, or Tefzel)
Common strengths of these coatings include good chemical resistance, the aforementioned non-stick nature of the coatings (particularly PTFE and FEP), and high temperature resistance compared to many other coating materials (FEP can take up to 400 °F and PTFE can withstand up to 500 °F).
However, the application methods for these coatings tend to leave a very thin layer of material, somewhere between 0.5 and 5 mils (thousandths of an inch) thick. Also, while these fluoropolymers are highly chemical resistant, they also tend to be porous, so they are not suitable for immersion applications.
When are Coatings a Good Idea for Your Basket?
Sometimes, having the right coating material can help to make a basket design more durable or useful for a particular process.
For example, a thick coating of PVC material can be useful for preventing a part from getting scratched by contact with the metal of a basket. On the other hand, polyester TGIC coatings can increase a base basket’s chemical resistance to prevent corrosion and prolong useful life.
When selecting a coating for a basket to improve corrosion resistance, it is important to consider whether it is more cost effective to use a coating, or to use a different alloy for the basket. If using a coating to act as padding, it is important that the coating is able to take the punishment involved with the parts washing or finishing process that the basket is to be used for.
A coating is a good idea when:
- It enhances the utility of your basket significantly.
- It is cost-effective compared to simply using a different base material.
- It significantly prolongs the useful life of your basket.
Want to know more about whether a given coating is suitable for your custom metal basket needs? Contact Marlin Steel to get answers to your parts washing/finishing basket questions!
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