I think over the years the terms Acrylic, Enamel, Polyurethane, Cellulose etc., have all been bastardized (sorry)
When learning about paints and their make ups as an apprentice, it was easy to remember which could be thinned or extended, and what was the correct medium to do this, and which could be applied over which safely
For example, the history of 'ACRYLIC' paints used on (mainly) American domestic vehicles in the late 40's through to 70's, was of interest to us aviation fans.
The acrylic used to manufacture aircraft canopies/windows etc,. was at an abundance immediately post war, and going to waste.
Someone (whose name I now forget) worked out that mixed with certain pigments and other chemicals, this medium could be used as a coating capable of protecting the surface it was applied to, at the same time as having a pleasing appearance, then known as 'ACRYLIC COATING' or 'LACQUER'
The American automotive industry was starting to accelerate post war, and saw this as the perfect medium to coat their huge, gas guzzling motors.
We here in the UK during the 40's, were still using oil based paints (ENAMELS) also known as (COACH PAINT) on our vehicles, gradually moving over to CELLULOSE based products, (who remembers BRUSHING BELCO)
.
Here was where the fun began for us automotive painters, and where we learnt the hard way, the incompatibility of coatings.
You could apply ACRYLIC over CELLULOSE (no reaction) You could apply ENAMEL over CELLULOSE (no reaction) You could apply ENAMEL over ACRYLIC (no reaction)
Apply CELLULOSE over ACRYLIC, ( stand back and watch the fun) not. Immediate reaction, pickling/cracking/crazing or reaction as the CELLULOSE coating dried.
Apply CELLULOSE over ENAMEL, exactly same reaction as CELLULOSE over ACRYLIC.
POLYURETHANE was a term we used for plastic based coatings, that gave a very high gloss (but some would say it looked too plasticky) and was found to be a problem to repair, if the surface was damaged. Second coating was a no no, it would react with itself if not recoated in a certain time period,(cracking/crazing) It also required to be baked to fully cure it, or left for 24 hrs.
We then moved onto 2 COMPONENT (2K) paint systems during the late 70's early 80's. Excellent gloss from the gun with minimal post paint buffing/polishing required.
However these were full of isocyanates and other Cancer/Asthma producing products, that were killing off us painters.
Now we come to modern vehicle Paint Coatings, which because of so called environmental reasoning, have to be 'WATER BASED'
The fact that most of the mediums used prior to applying the (water based colour) and the finish Clear Top Coat, now called 'LACQUER,' are still full of undesirable products seem to have been missed somewhere.
Now getting back to my original point, the messing about with the names for the different paints/mediums.
LACQUER is now a clear medium, ACRYLIC is now a water based medium, ENAMEL seems to be the only one that has retained it's original medium.
However some oil based 'GLOSS' paints will react when over coated with ENAMEL.!!!!!!!!!!!
I haven't included the specialist paints such as POWDER COATING, HAMMERITE, CRACKLE, VREEBLE, COBWEB, and too many more to mention.
Most people just see paint as, well paint!
Gregg
