The Differences Between Acrylic Enamel and Urethane Auto Paints
Posted: December 21, 2020 By: MattM
Automotive painting has really jumped leaps and bounds over the years. The early days of automobiles they were treated more like a horse and buggy or carriage and many parts were hand painted with a brush. While Ford was the first to really begin mass produce automobiles on an assembly line they began spraying them with liquid paint sprayers; but the “enamels” they used then weren’t anything like what we call enamels today. As years went on manufacturers switched to lacquer paint and then on to Acrylic Enamels and Urethanes of today’s standards. Because of the changes in paints it’s hard to get true lacquer and real early Enamel or “color varnishes” of the old days is impossible to find. For that reason the two most common choices for painting your car are acrylic enamel and urethane paints. So why these paints and what are the pros and cons? We discuss more below.
Acrylic Enamel Paint
- Slow Drying Times- Acrylic Enamel Paint is traditionally a 1-part paint and doesn’t require a hardener or activator. These air-dry much like a stain or varnish would in the woodworking world. So if it’s cold outside or no direct sunlight on the vehicle after paint it could take days for the paint to be workable.
- Chips Easily- Because There is no hardening agents in Acrylic Enamel the paint tends to chip easily so it needs to be handled with care especially until fully dry.
- Life of Paint- While the paint may be easier to prepare and spray to some the longevity of Acrylic Enamel is shorter than modern 2K Urethane paints. If you’re spraying a show-queen that will almost never see weather it may last a lifetime, but most Enamel paintjobs do have a life cycle and need to be resprayed after a number of years. This is why you’ll rarely see an old enamel paintjob that has been out in the weather that doesn’t have fading, cracking, etc.
2K Urethane Paint
- Mixing Ratios- Due to Urethane Paints requiring a minimum of two parts (paint and activator/hardener) there needs to be extra care in mixing ratios, decisions on speed of activator based on your spraying technique and temps outside when spraying. Once you’ve got the basic process down you can even test out adding thinners or additives to your Urethane Paint to really dial in how it sprays and lays out.
- HVLP Gun Required- The old days of spraying with an old school Binks Siphon sprayer are gone when using modern Urethane Paints. The droplet size and pressure required to spray urethane paints really leans towards using a modern HVLP paint gun. While we aren’t saying you can’t use a siphon gun; the results may be lack luster due to the way these types of guns deliver the paint to the surface. ‘
- Matching Sheen- The one downside if you are restoring an old car or trying to match original sheen of enamel paint on a classic car is the natural depth and sheen of a urethane paint is much higher than that of an enamel paint. Therefore it can be hard to match the sheen of an old lacquer or enamel paint job with urethane paints. Luckily there are options to get it close with using flattening agents in the paint and polishing the paint to match the sheen you’re after but it is definitely something that takes some practice and experience.
We think hands-down Urethane paints are the best for a DIY paintjob and tend to be quite user friendly and very affordable. With 100’s of color options you’d be hard pressed not to find what you need for your next project. Find our full line of Urethane Paints HERE.