How To Choose the Best Paint Thinner Author – Andy Potts October 6th 2020 (reading time 3 mins)
(Paint thinners – there are numerous types and brands)
All paint thinners are not made equal. Some are designed for cleaning brushes, guns and equipment; others are for use with oil-based paints, stains and varnishes to provide a superior finish. The key to achieving a top-notch paint job is understanding which type of thinner to use for which situation.
What are paint thinners?
The term’ paint thinner’ refers to a generic group of solvents and solvent blends that can dissolve oil-based coatings and reduce their viscosity. The most commonly used chemicals in thinners include:
- Acetone, Dimethylformamide (DMF)
- Glycol ethers
- Methyl ethyl ketone (MEK)
- Mineral spirits (white spirit)
What’s the difference between thinners for cleaning and thinners for spray application?
Purity is the weapon of a paint thinner – the more pure; the better the finish. Thinners that contain a high volume of particles and recycled solvent content are only suitable for cleaning. The debris will clog your spray gun and contaminate your finish if you try to use these lower quality thinners with paint.
What happens if I don’t use paint thinner?
Thinner is used to allow the paint to atomise through the spray gun correctly and give a fine finish. If you are using a high pressure airless paint system then you may not require thinner as the pump will force the paint through the nozzle at high pressure.
However if you are using a conventional spray gun without thinner, the paint could dry matt, have orange peel effect or a very uneven finish.
Can I use gun wash or standard thinners in my paint? We would never recommend using gun wash or standard thinners in paint. These products are recycled solvent and have varying quantities of water in the solution. When putting this in paint it will likely cause major problems including not drying, blooming, going matt or flaking off the substrate.
Paint Blooming sometimes known as Blushing is explained here:
Can you use too much thinner?
If you put too much thinner into a paint mix it can cause major problems with your finish. Solvent can get trapped in the layers of paint and this causes solvent popping.
Get a view of what solvent popping is here:
If you add too much thinner to your paint mix, the paint can become too thin and you get runs and sags in the finish. Drying times can also be affected with the paint drying too fast and going matt, or too slow and staying soft.
Watch why slow paint drying times can cause various issues apart from the obligatory ‘ watching paint dry’:
What happens if I use the wrong thinners?
Sometimes you are lucky and it has no adverse effect. However mostly it will either react straight away in the tin and separate or will do it later when it has been sprayed onto your substrate.
Uses: DIY and commercial paint stripper.
Rustoleum Green is a powerful, quick-acting paint stripper that makes light work of removing old layers of paint, varnish or glue. It doesn’t contain methylene chloride and can be used at low temperatures, making it safe to use in more vulnerable environments and in the home. Rustoleum Green will remove all types of oil and alkyd-based paints, emulsion, varnish and most two-component products from metal, mineral and wooden substrates.
It’ sowrth noting that you cannot place paint stripper in paint. Paint stripper is a purpose produced chemical to strip paint off a substrate. If you add paint stripper to paint as a thinning fluid then it will result in the paint simply falling off your project.
Check out the video below for paint lifting from surfaces:
Uses: paint stripper
This industrial-strength paint stripper does what it says on the tin. Use it to remove any coating, including two-pack acrylic and polyurethane.
White spirit cuts through oil and oil-based paints with ease.
NOTE: Rustoleum Green, Ultrimax Heavy Duty Paint Stripper and white spirit are too harsh to be used as a cleaning agent or paint thinner.
Uses: metal surface preparation
Panel wipes are designed to lift dirt and particles from metal panels in preparation for painting. This product evaporates quickly to leave a streak-free clean surface.
Uses: specialist degreaser, solvent and thinner for epoxies, resins, adhesives and lacquers
MEK is a strong, slow-drying thinner for epoxies, lacquers, adhesives and polyester resins used in fibreglass repairs. It is also ideally suited to removing these materials from cement, tools and other surfaces.
CAUTION: MEK is a highly volatile and flammable solvent that evaporates quickly. Always use and store this product as specified on the manufacturer’s product data-sheet.
Uses: cleaner for spray equipment and removal of excess paint from spray lines
This aggressive solvent is ideal for cleaning. Don’t be tempted to use it as a paint thinner unless you’re looking for the “rippled finish” effect!
Uses: brush and equipment cleaner, thinner for single-pack primers
Standard cellulose thinner is an excellent brush cleaner and gun wash thinner. It can also be used as a thinner for single-pack primers but isn’t pure enough to be used with topcoats.
Uses: topcoat thinner
If you want to achieve a high-gloss finish, this is the product for you.
The short video below explains the difference between standard and cellulose thinners in detail:
Uses: thinners for Sayerlack wood finishes
Sayerlack thinners have been developed specifically for thinning Sayerlack two-pack paint products. They are not suitable for use on metal surfaces.
Uses: equipment cleaner and thinner for the Jotun acrylic, vinyl and antifouling coatings
NOTE: It is advisable always to use a same-brand paint system as the thinners, primers and topcoats are formulated to withstand and work with each other.
Uses: thinner for single-pack paints
This high-gloss thinner will achieve a premium glossy finish with most single-pack paint systems, including alkyd and acrylic.
Uses: thinner for single-pack and polyurethane paints
A universal thinner for most single-pack synthetic and polyurethane paint products such as Ultrithane. [link to a specific product in the range?]
Uses: cleaner, degreaser and single-pack paint thinner
Xylene is an excellent all-rounder and a top-selling Ultrimax product. It contains very little recycled product, making it a suitable thinner for inks, varnishes and all single-pack paints that will be topcoat finishes. Use it with Ultrimax 1, Ultrimax Gloss, Ultrithane, Ultriprime, & Ultrimax SGX. Xylene can also be used as a cleaner or degreaser on metal surfaces.
Uses: thinner for etch primers
Etch Thinners is a specialist product fur thinning etch primers (used to coat surfaces such as galvanised metal and aluminium that require an etch). Not recommended for thinning topcoats.
Uses: thinner for two-pack paints
A universal slow thinner for most 2K acrylic and polyurethane paint systems.
Uses: thinner and additive for electrostatic paints
Electrostatic thinners helps to get a better wrap round effect on the substrate of paint coverage( a key benefit of electrostatic systems being the reduction in paint usage) but the negative is that it extends the drying time of the paint.
Struggling to get your hands on industrial thinners for your paint shop?
Industrial quantities of thinner are like gold dust these days. Transporting the base chemicals needed for these products is a challenge, and there is a rising supply issue as a result. But don’t worry. Ultrimax has you covered. We have an excellent supply network, allowing us to stock quantities of 5 litres and above.
Need more advice on how to choose a paint thinner?
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