When working with Automotive Industrial Basecoats, there are a lot exciting applications in the form of pros and cons, aka these basecoasts can be a Beauty or a Beast.
The Beauty of Industrial Basecoats
1) Automotive refinish basecoats are phenomenal – Thousands of different hues; color matches for present vehicles and some going back as far as 20 years; reds, blues, greens, yellows, blacks, whites, greys, beiges, metallics, micas, fluorescents, candies, chameleons, etc. The possibilities are endless and eye-catching. The color of any vehicle is probably the number one selling point for consumers.
2)The best automotive basecoats are formulated to dry fast, hide/cover in the minimum number of coats, orientate metallic flakes perfectly, and handle easily.
However, behind every basecoat beauty, there lurks a beast, waiting to raise it’s less-than-beautiful head!
The Basecoat Beast
For all their beauty and positive attributes, the fact of the matter is that all 1K basecoats are lacquers. There is no “chemistry” as far as crosslinking that takes place in basecoats.
ortunately, the basecoat is sandwiched between two chemically crosslinked layers; the 2K polyurethane or epoxy primer and the 2K polyurethane clearcoat.
In fact, the 2K polyurethane clearcoat chemistry is so strong that it compensates for the basecoat’s weakness underneath it and protects the basecoat from sunlight (UV), moisture (rain, humidity, etc.) and physical damage (scratches, rock chips, etc.).
However, the 2K polyurethane clearcoat can only do so much! The problem arises when too much basecoat is applied. This is especially possible with poor-hiding, semi-transparent colors, like bright reds, yellows, and greens.
The so-called “candy colors” are perfect examples of this. If the dry film thickness of the basecoat exceeds 3-4 mils, there is a danger of peeling or delamination of the clearcoat. This problem can be compounded if the multiple coats of basecoat have not been allowed to dry properly between coats.
What Can You Do to “Tame the Automotive Basecoat Beast”?
A trick which has been used by people in the RV/motorhome industry for years is to add a small amount of hardener to colors which are poor in hiding to impart a chemical link to the clearcoat and also ensure good adhesion to the primer or substrate.
Usually, 5% of the same hardener that’s used in the clearcoat to reduced gallon of basecoat can provide a safety net against peeling or delamination.
This “activated basecoat” will remain fluid – without gelling – since the hardener level is so low. But the activation will lose its effectiveness in 24-48 hours. It’s a small price to pay to tame the beast!