Plastisol Vs. Teflon: Which Coating Do You Need?

Specialized polymer coatings can do a lot to add to the utility and durability of a custom wire basket. With the right basket coatings, you can prevent damage to delicate parts during intense parts cleaning processes, minimize the risk of chemical corrosion (by keeping the chemicals from touching the basket itself), and/or prolong the useful life of an expensive precision-engineered custom wire basket.

However, to accomplish these goals, it’s important to choose the right basket coating for the job. Picking the wrong coating can be a waste of time and money—and even make the basket actively worse at whatever task it was built for. So, a lot of Marlin’s customers ask the following question: “Is coating X better than coating Y?”

The answer is: “It depends on what the application is.” For example, two popular coatings that get used in many different manufacturing applications are Plastisol and Teflon® (Teflon® being the brand name of a family of coatings owned by Chemours).

To help you determine which of these two basket coatings is the best for your needs, here’s a quick comparison of Plastisol vs Teflon®:

The Properties of Plastisol

Plastisol can be an interesting material because of how variable its properties are depending on the specific mixture used and how it is applied to a basket. For example, the hardness of Plastisol can vary between a rating of 35A to 95A on the durometer scale (basically, from the hardness of a pencil eraser to the hardness of plastic skateboard wheels).

Even at its hardest, Plastisol coatings aren’t especially hard. This makes Plastisol a popular coating for ultrasonic cleaning processes, where a semi-soft surface can be useful for minimizing the risk of scratching parts.

Likewise, the maximum use temperature of Plastisol can vary. Some formulations of this basket coating have a maximum use temperature of ~200 ˚F (93 ˚C), while others can take up to ~300 ˚F (148 ˚C). If oven-like temperatures are an issue for your manufacturing process, you may want to specify which formulation of Plastisol you need, or even go with a more temperature-tolerant basket coating.

There are two general methods of applying a Plastisol coating to a custom wire basket:

1. Dipping Baskets in Liquid Plastisol. Here, a basket (or other metal form) is dipped in a bath of liquid Plastisol. The Plastisol coating sticks to the item being dipped—forming a thick and soft coating. This is often used for tool handles in home applications. These coatings only cover the parts of the basket that were submerged in the Plastisol, creating a clear “dip line.” This method is not preferred for fine wire mesh, since it can cause webbing and messy drip marks.
   
   
2. Fluid Bed with Powdered Plastisol. Instead of dipping a basket in liquid Plastisol, the fluid bed process takes a heated basket and dips it into powdered Plastisol (or a cloud of ionized Plastisol power, which is called the electrostatic fluidized bed coating process). This method tends to create a much thinner coating than the dipping process (being 15-20 mils, or 0.015” – 0.020”), which minimizes the risk of webbing. Also unlike dipping processes, fluid bed processes tend to coat the entire custom wire form—which is ideal for applications where the basket will be completely immersed in water or other chemicals.

What Are the Properties of Teflon®?

Teflon® is pretty much a household name at this point—famous for being used in home cookware as a nonstick coating. The thing is, the term Teflon® covers several different coatings:

1. Polytetrafluoroethylene (PTFE);
2. Fluorinated Ethylene Propylene (FEP);
3. Perfluoroalkoxy (PFA); and
4. Ethylene-tetrafluoroethylene (ETFE, or Tefzel®).

Each of these polymers under the Teflon® brand name have different characteristics, so generalizing can be a bit difficult. However, some common characteristics of these basket coatings are that they tend to be very porous, have nonstick properties, and are typically applied in very thin layers—around 0.5 – 5 mils (0.005” – 0.050”) thick.

The most common types of Teflon® coatings that are applied to custom wire baskets tend to be PTFE and FEP. Both of these basket coatings have exceptionally high temperature tolerances compared to most other polymers—FEP can take temperatures up to 400 ˚F (204 ˚C) and PTFE can withstand temperatures up to 500 ˚F (260 ˚C). This makes both of these coatings more suitable for high-temp applications than Plastisol.

These coatings also tend to be fairly hard—for example, FEP coatings rank 56 Shore D on the durometer scale (about as hard as a cart’s caster wheels). It should be noted that other formulations of Teflon® (like PFA and ETFE) are harder than this on the durometer scale.

Because Teflon® coatings are so porous, they aren’t generally preferred for total immersion applications, like ultrasonic parts washing, since chemicals can seep into the cracks to attack the basket being coated directly.

So, which is Better, Plastisol or Teflon®?

If your manufacturing process involves high temperatures and some rough treatment of the basket, then Teflon® basket coatings may be your best option. The temperature tolerance and durability of these coatings helps to ensure a long useful life in oven-like conditions.

However, if your application involves total submersion in liquids, or you have extra-delicate parts to protect, then a Plastisol coating may be the better option. These coatings are just a bit softer and better at protecting coated baskets from chemical attack.

Of course, there’s a lot more that goes into choosing a custom wire basket coating than just temperature and whether your basket will be submerged. If you need help picking the right basket coating (or other basket design features), reach out to the Marlin Steel team to get started.