Measuring E-coat Throwpower
Throwpower has become a very popular and powerful word in the cathodic epoxy electrocoat industry.
So-called high-throw electrocoat is designed to improve the effectiveness and productivity of e-coat application; material consumption decreases, higher line speeds and greater rack density are some of the claims attributed to the technology.
Are these claims true? What is throwpower, and why has it vaulted to the top of electrocoat attributes?
The conventional definition of throwpower is electrocoat’s ability to be deposited in recessed areas. In fact, this is electrocoat’s main advantage over other coatings since it provides corrosion protection in difficult-to-coat areas.
Conventional electrocoat throwpower is measured using a two-panel throw box, which determines the distance electrocoat “throws.” The box panels are set a distance apart, sealed on the sides and open on the bottom. The box is then coated in an electrocoat bath in the laboratory under defined conditions. The result is that the exterior of the box is fully coated and the interior is only partially coated. The distance of the interior coating is measured, and this is the e-coat’s throw.