Coatings for Custom Parts Washing Wire Baskets Part 1: Plastisol

In Custom Wire Baskets, Coatings for Baskets & Racks, Steel Wire Products

Drew Greenblatt on May 23, 2014

Plastinal - Parts Washing Wire Basket Marlin SteelHere at Marlin Steel, we get many questions about the properties of different coating materials. Recently, a client asked about a coating material called Plastisol. More specifically, the client wanted to know how well this coating would hold up to sliding down a ramp.

The answer to this question is: it depends.

There are a number of factors that can influence how well a Plastisol coating will survive sliding down a ramp, such as:

  • The smoothness of the ramp.
  • The specific hardness of that sample of Plastisol. Plastisol’s hardness can range from 35A on the durometer scale (about as hard as a pencil eraser) to 95A (about as hard as a skateboard’s wheels).
  • The length and angle of the ramp.
  • The weight of the parts being held in the basket.
  • The surface area of the basket.

In order to maximize the life of a Plastisol coating, it is advisable to make the ramps as smooth as possible, either by using rolled cold metal or a series of rollers for the ramp. Furthermore, the transition at the bottom of the ramp should be gentle and smooth.

If abrasion wear from sliding down a ramp is going to be an issue, there are other coatings that are harder than Plastisol which would work better in that situation.

How Plastisol is Applied to an Item

When used as a coating, Plastisol can be applied to an object through two different processes: dipping and the fluid bed process.

DIPPING. The dipping process for Plastisol is the one that most consumers are familiar with. In this process, an object is partially submerged in liquid Plastisol and then removed. This process is commonly used for objects that are much thicker than a wire form, such as pliers and baby spoons.

Dipped Plastisol coatings tend to be very thick and are commonly soft, perfect for tool handles that need to be easy to grip, but gentle on the hands. A telltale characteristic of an object that has been dipped in plastisol is the presence of a clean, flat “dip line.” Total immersion is not common in the dipping process.

For fine wire mesh, the dipping process is not the preferred method of applying Plastisol. Dipping typically results in “webbing” in the mesh and messy drip marks that may require manually stripping the excess material.

FLUID BED. The other process for applying Plastisol is known as the fluid bed process. Instead of dipping an object in liquid, this process starts with powdered Plastisol. A part is either heated and dipped directly into the powder or is passed through an ionized cloud of powder (sometimes referred to as electrostatic fluidized bed coating).

The advantage of the fluidized bed coating application process is that it allows for an exceptionally thin, even coat of Plastisol over an object. Typically speaking, this method creates a coating that is between 15 and 20 mils (0.015” and 0.020”) thick.

Unlike the dipping process, the fluid bed process does not do a “partial” coating. This process coats the whole of the item. Naturally, it can be trimmed afterwards, but it will not have a clean “dip line”, as the other process produces.

The fluid bed process is generally better for wire forms, as it can be applied to objects with a small surface area with great consistency and much less wasted Plastisol material than dipping. This process is much less messy on fine wire mesh than dipping, and generally will not require as much stripping.

Unless you need an especially thick coating for your wire basket, the dipping application is not recommended.

Properties of Plastisol

Once the Plastisol has been applied to an item, either by dipping or by using the fluid bed process, it becomes a form of polyvinyl chloride (PVC) when it is finished curing. The specific properties of the material can change depending on the plasticizer and the process used to apply it, however.

For example, this form of PVC has a wide hardness range, as was mentioned earlier. The form of the coating that we use, however, is typically around 80A, give or take a couple of points on the Shore durometer hardness scale. This means that the Plastisol we use is harder than a common car tire, but less hard than a hard plastic skateboard wheel.

Most forms of Plastisol have a maximum use temperature of 200 °F, although some formulas can take temperatures in excess of 300 °F. If temperature extremes are an issue, be sure to specify the proper formulation for your application. This coating can be made in very nearly any color you want. While gloss coatings are the most common, matte versions of the coating are also available.

For more information about using Plastisol on your material handling baskets, contact us today. Our engineers can answer your questions and make recommendations about alternative coatings that can meet your needs.

Author: Drew Greenblatt
Drew Greenblatt
Drew Greenblatt bought Marlin Steel Wire Products in 1998 when it was a small maker of a commodity product. Since then, it has grown revenue seven-fold. In the face of challenges to the global economy, Marlin Steel has invested more than $3.5 million in robotics in a quest for quality and speed.

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