Lacquer Thinner vs Denatured Alcohol

In this article, learn about lacquer thinner and denatured alcohol. After defining each substance I’ll share the similarities, differences and major differentiating factor. Then, I’ll tell you when to use them and which is better. 

What Is Lacquer Thinner?

Lacquer thinner is an imprecise term applied to any amalgamation of strong solvents used to dissolve lacquer. It is also known as cellulose thinner. There is no precise formula for lacquer thinner, and without a chemistry set, it’s difficult to know what your lacquer thinner contains. 

Lacquer thinners traditionally contain harsh solvents such as ketones (like acetone or methyl ethyl ketone), alkyd esters (like butyl and amyl acetate), alcohols, ethers, and aromatic hydrocarbons. 

Lacquer Thinner Properties

These solvents emit volatile organic compounds (VOCs) that vaporize when exposed to air and room temperature conditions. This phenomenon is called ‘off-gassing’. The presence of VOCs lowers the air quality indoors and is linked to a range of short and long-term negative health outcomes. 

Consumers and manufacturers have become aware of these effects and have sought low-VOC alternatives. Regulatory restrictions on the amount of VOCs that household products can contain have furthered the search for low-VOC alternatives to traditional lacquer thinner. 

Today, products labeled low or no VOC lacquer thinner are mostly acetone and aromatic hydrocarbons. Traditional lacquer thinner has a strong and unpleasant odor that tends to linger after use. Low-VOC formulations can be nearly odor-free. 

Lacquer Thinner Uses

Lacquer thinner is used (as the name implies) to thin lacquer. 

Lacquer is a high-gloss film-forming wood or metal finish made from resin dissolved in solvents. The resins used can be natural, as in the case of shellac, or synthetic, as in the case of vibrant acrylic lacquers. It cures to a hard, durable, waterproof finish that is slick, smooth, and easy to wipe clean, making it popular for cabinet fronts in kitchens and bathrooms. 

It is a fast-drying finish that is usually applied via a paint sprayer. On its own, it is too thick to easily move through the hoses and nozzles of a sprayer. Lacquer thinner’s primary use is to reduce the viscosity of lacquer to an acceptable thinness for spray application. 

It can also be used to correct and repair lacquer finishes, although it is a bit aggressive for this purpose. When lacquer finishes eventually degrade, lacquer thinner is the quickest and easiest non-abrasive method of removal. 

What Is Denatured Alcohol?

Denatured alcohol, also called ‘methylated spirits’, is a modified ethanol product. The nature of alcohol is to be consumable. To ‘denature’ it, additives are mixed into the pure ethanol that make it unfit for human consumption. 

Pure alcohol will achieve many of the same results as denatured alcohol, but as a recreational substance it is heavily taxed. Because denatured alcohol is undrinkable, it can be sold in hardware stores, and is available to purchase without age restrictions. In many places, manufacturers are required to add blue or purple coloring to the container to distinguish denatured alcohol from drinkable versions. 

Denatured alcohol is not just unpleasant tasting, it is poisonous if ingested. Methyl, the most common ingredient used to denature alcohol, has a history of causing blindness. Pyridine, gasoline, castor oil, benzyne, and acetone are other common denaturers. 

Denatured Alcohol Characteristics

Denatured alcohol is: 

• Clear
• Watery
• Liquid
• Highly flammable
• Toxic

Denatured Alcohol Uses

Denatured alcohol is used as a degreaser and solvent in a variety of arenas. 

Woodworking

Denatured alcohol combined with lac resin forms a liquid, film-forming wood finish known as shellac. A wipe of denatured alcohol will refresh an old shellac finish and help correct mistakes during the application process. You can remove shellac using denatured alcohol, or simply thin it to your desired concentration.

It can also be used to remove paint from surfaces.

Automotive

When cleaning automotive parts for repair, maintenance, or replacement, denatured alcohol is often the solvent of choice. It quickly and effectively strips away oily or greasy residue from metal. In fact, it is so effective that re-lubrication is usually necessary before the part can be replaced.

Because denatured alcohol evaporates quickly, using it as a degreaser minimizes the metal’s exposure to moisture. This helps prevent the corrosion that causes rust. 

Home

Around the house, denatured alcohol is the solvent of choice for removing stickers, labels, glue and tape from wood, plastic, glass, metal, or tile. When diluted, it cleans glass, windows, and mirrors without leaving unsightly streaks behind. 

Undiluted denatured alcohol can be sprayed on moldy or mildew-y areas to help remove the fungus and discourage it from regrowing. It is usually mixed with a mild detergent for this purpose. It can also remove ink stains from certain types of fabric. 

Garden

Mealybug and red spider mite infested plants can be wiped or spritzed with denatured alcohol to kill the pests. The substance should be diluted with water first. 

Fuel 

Denatured alcohol is used to increase the octane rating of fuels such as gasoline. This supports advanced ignition timing and forced-air induction-powered turbochargers. High-octane fuels generally include denatured alcohol. When added to the tank of small internal combustion engines such as lawnmowers, it significantly reduces emissions. 

Learn more about the similarities and differences in denatured alcohol and mineral spirits.

Lacquer Thinner vs Denatured Alcohol

Denatured alcohol can be an ingredient in lacquer thinner, but it also stands on its own. These two solvent substances have areas of overlap, such as their flammability. They differ in formulation and the availability of no-VOC alternatives. 

Similarities

Both lacquer thinner and denatured alcohol are solvents used to strip metal and wood. 

They are flammable materials that need to be kept away from sources of ignition. 

Both substances emit VOCs and require respiratory protection to apply. 

Differences

Denatured alcohol is a single ingredient solvent. Lacquer thinner is an artful term that doesn’t tell you much about what is inside the can. 

No-VOC formulations of lacquer thinner are available. Denatured alcohol emits VOCs, although not at the rate of traditional lacquer thinner. 

Major Differentiating Factor

Denatured alcohol has a wide variety of applications and uses, and can be used to thin finishes, including lacquer. 

On the other hand, lacquer thinner has only one use – to thin lacquer. 

When to Use Lacquer Thinner

Use lacquer thinner only with lacquer. 

Adding lacquer thinner to lacquer before application will make it easier to apply, whether you’re brushing or spraying it on. Beware, it will also speed the already-quick dry time of lacquer, so you may need to compensate with a lacquer retarder. 

Lacquer is an unforgiving finish. Each layer must be perfect before another layer can be added. Correcting imperfections during the application process can be done with lacquer thinner. 

When you want to remove every trace of lacquer from a wooden or metal surface, lacquer thinner is the best choice. 

When to Use Denatured Alcohol

Use denatured alcohol to make shellac. It can also be used to refresh and revive film-forming wood finishes. 

Around the house, use denatured alcohol to degrease and destick, removing glue, tape residue, stickers, and labels. You can clean glass with denatured alcohol for a streak-free shine. It will remove ink from most fabrics. Denatured alcohol also removes light pencil marks on wood. 

It can also be used to degrease and clean metal, and is particularly effective at removing sap from garden tools. 

Spraying denatured alcohol on house plants is an effective pest control solution for red spider mites and mealybugs. 

Which Is Better, Lacquer Thinner or Denatured Alcohol? 

Lacquer thinner is best for thinning, correcting, and removing lacquer finishes on wood and metal. 

Denatured alcohol is best for working with shellac or removing sticky substances from wood, metal, tile, plastic, and glass.