Oil-based versus Water-based Paints

September 01, 2018

Categories: Coating Solutions, News, Paint Knowledge

The distinction between oil-based versus water-based paints was established when latex house paints were introduced in the 60’s. Until that time, architectural and industrial paints and equipment could not be thinned or cleaned up with water, but instead required a solvent-based thinner. Most of these thinners are derived from petroleum products and the paints that contained these thinners are known as “oil-based”.

Latex paints made a huge change in the market because they could be thinned with water, and equipment clean-up became much easier and faster.

All paints contain some thinner that is added at the factory. The thinner, either an oil-based solvent or ordinary water, is added to thin, or reduce the factory mixture so the paint can be brushed, rolled, or sprayed.

There are other differences between oil and water-based paints besides their obvious chemical makeup:

  • Ambient temperature conditions differ on how or when they can be applied and stored, with water-based paints being more restrictive.
  • Water-based paints are generally more environmentally friendly and are a consideration when dealing with regulatory requirements, waste management, air quality, or worker safety.
Table comparing oil-based and water-based paint features

Table comparing oil-based and water-based paint features

Carbit Paint produces both oil-based and water-based paints for a wide range of industrial uses. For more information when comparing your options, call 312-280-2300 and ask for Dave Westerman Jr. (ext 312) or Bob Lyons (ext 344).


PREDICT THE THICKNESS OF PAINT

November 21, 2014

Categories: Coating Solutions, News, Paint Audit, Paint Knowledge

It is easy to predict the thickness of paint after it dries. All that is required is that you know the “percentage of volume-solids” of the paint and that you have a “wet-film-thickness gauge”. The paint’s volume-solids (not to be confused with “weight-solids”) is listed on the Product Data Sheet, which can be found on the paint manufacturer’s website. A “wet-film-thickness” (WFT) can be purchased at professional paint stores or online, or obtained Free from Carbit.

Free WFT gauge In previous articles I discussed “paint volume solids”, which I described as “what’s left after the paint dries”. In that article I explained that as paint dries it shrinks in direct proportion to its volume solids. For example, a paint with 50% volume solids will lose one-half of its volume as it dries. If it is 4 mils when wet it will be 2 mils thick (4 x 50%) when dry.  Paint Volume Solids Wet Film Thickness Fortunately, the

Wet-Film-Thickness (WFT) of a coating can be easily measured with a Wet-Film-Thickness Gauge.

To use a WFT Gauge you depress the graduated edge of the gauge into the layer of wet paint immediately after it has been applied. Withdraw vertically and note deepest tooth having paint on it and the next higher tooth that is not coated with paint. The true wet film thickness lies between these two readings.

 

In the U.S. the thickness of paint is expressed in mils (one mil equals 1/1000 of inch). The rest of the world expresses coating thickness in microns (1 micron = 1 millionth of a meter and 25.4 microns = .001” inch or 1 mil). The table below compares the thickness of common materials in mils and microns. table of comm mtrls

Being able to predict the thickness of paint has many practical benefits:

  • It ensures that you are applying the correct amount of paint to achieve the performance properties of the coating.
  • Coating thickness correlates to dry-time, recoat time and appearance.
  • And, the ability to predict the thickness of paint helps you control cost.

For more information or help to predict the thickness of paint that you are applying complete our “get-in-touch” form below or call us at 312-280-2300. Bob Lyons – Carbit Paint Company, LLC – November 2004


Understanding Paint Volume Solids

September 29, 2014

Categories: News, Paint Knowledge

Understanding paint volume solids provides many benefits:

  • It allows you to compare the true cost of different paints.
  • It allows you to predict how much paint must be applied to obtain adequate coverage.
  • It allows you to control the quality of the paint job.
  • It allows you to avoid production delays because thick layers of paint dry more slowly.

Understanding paint volume solids begins by recognizing that as paint dries some components evaporate while other components are deposited on the surface. What evaporates is mostly the thinner, either water or a solvent which has been added to the paint so that it can be applied.   In the simplest terms, the volume solids are “what’s left after the paint dries.”

VOL SOLIDS smV2

Paint manufacturers express “volume solids”* as a percentage of the total volume. This information can be found on the paint’s technical data sheet and sometimes on its label.

For liquid coatings the “paint volume solids” can vary widely depending on the type of paint and its purpose. For example:

Paint Type Vol. Solids %
Sealers 10-25%
Architectural Paints ** 35-45%
Industrial Enamels 25%-45%
2K Epoxies 40%-80%
2K Polyurethanes 30%-45%

By understanding paint volume solids you can calculate how much of each gallon of paint remains on the surface to perform its function. Higher volume solids are not necessarily better than lower volume solids, it really depends on the type and purpose of the coating, and higher volume solids usually means a higher price per gallon.

There are many benefits in understanding volume solids of coatings. In future articles I’ll discuss how to convert volume solids to spread rate and dry-film-thickness, but for now it’s worth remembering that volume solids differ between coatings and knowing the difference can provide many benefits.

 *Don’t confuse “volume solids” with “weight solids”. Volume solids predicts how much area a paint will cover and weight solids indicates the weight of the non-volatile ingredients.

**Low VOC paints may have higher “volume solids”

By Bob Lyons, CARBIT Paint Co., LLC.