Remains of shellac residues in a spray gun can clog its spray nozzle and fluid passageways. That can result in a poor paint job due to disruption of fluid flow and atomization (reduction of paint to tiny droplets) in the spray gun.
On that note, it is important to clean your spray gun right after spraying shellac or before spraying another finish with it. This article will cover how to clean shellac out of a sprayer and brush. But first, let us look at what shellac is.
What is Shellac?
Shellac is a natural finisher – a secretion of a female lac bug that feeds special trees in Thailand and India. The resin is then taken to a factory to process and remove contaminants such as insect larvae. You can use it to enhance the wood’s natural grain and come up with a fine and mellow finish.
It’s also edible and can be found on coatings, medicine, or candy. Shellac can be used as a primer, sealer coat, and high gloss varnish. It also has blocking properties such as blocking odor, silicone contaminants (causes fish eye effect) and seeping through of oils from exotic woods.
Shellac is available in many colors, making it a versatile finisher. The most common ones are orange and white. Orange shellac produces an amber color on dark woods. It creates a nice finish with mahogany, teak, and walnut. You can use white shellac on lighter wood.
Pros of Shellac:
- It dries fast.
- It’s easy to apply.
- It’s easy to repair.
- It’s UV resistant.
- It doesn’t darken or become yellowish with age.
- You can apply it over fillers and stains (except alcohol-based ones) and under top coats such as lacquer, polyurethane, or varnish.
- It’s non-toxic
Cons of Shellac:
- It’s prone to damage.
- It can lead to the hardening of your brush to a point where you can’t reuse it.
How to Clean Your Spray Gun after Running Shellac Through It
It would be best to clean a sprayer with shellac immediately after use. Cleaning brushes in the kit with a spray gun come in handy when cleaning a spray gun. Cleaning shellac out of a sprayer, brush, or roller involves removing the shellac but not thinning it. That’s why using alcohol alone won’t cut it. Alcohol and ammonia are the go-to solvents when you want to clean shellac from the brush or sprayer you’ve used to apply – cleaning with water alone results in clogging of the sprayer since the shellac solidifies inside and leads to the formation of chunks.
Alcohol dilutes the cut of the shellac present in the sprayer. Ammonia, on the other hand, breaks down the shellac for easy removal with warm water. Remove the fluid cup, air, fluid nozzles, and other removable components from the spray gun and soak them in denatured alcohol while washing them with the cleaning brushes.
Soaking the gun in alcohol can lead to problems such as damage to seals and packing in the spray gun. The contaminated alcohol may also flow into the sprayer’s air passages and clog them.
Run the alcohol repeatedly through the gun. You can also use alcohol to dissolve hardened shellac in the spray gun. Use a mixture of ammonia and water (with a ratio of 1:1) to clean up faster and thoroughly.
It’s the best and most effective way of cleaning up your spray gun and brushes you use with shellac unless you’re planning to reuse them within the next few days. In that case, denatured alcohol is convenient if you want to use it within a day or two.
Mix ammonia and a little water and cycle the mixture through the sprayer to eliminate any clogs. Soak the spray gun in 5 gallons of ammonia and water mixture to remove any traces of shellac left in the spray gun.
The clean-up works even if the shellac has hardened in the spray gun. You can also use a solvent called MEK (Methyl Ethyl Ketone) to dissolve and remove any hardened shellac in the spray gun. Rinse the spray gun with warm water after cleaning.
Using a Spray Gun Cup Liner to Speed Up and Make Your Cleaning Easier
A spray gun cup liner is placed inside a paint cup of a spray gun. Its main function is to create a barrier between the paint cup and the paint you’re using, which in this case is shellac. You can therefore use it to make clean-up and switching of colors faster and easier.
If you prefer using a brush to apply shellac since it takes a shorter time to build film thickness, here’s how you can clean it after use:
How to Clean Your Brush after Using Shellac
You can also use denatured alcohol and ammonia to clean and store the brush once you use it to apply shellac. If you want to use the brush within a day or two, hang the brush in denatured alcohol, ensuring the bristles are not bent at the bottom. Don’t cover the bristles completely with alcohol, as it will wick up the bristles.
If you’re not planning on using the brush any time soon, dip it in ammonia and water mixture (ratio of 1:1). Firmly press it a couple of times to the bottom of the container. This is to remove most of the shellac present on the brush.
The mixture works by emulsifying (blending with) shellac to allow removal with water and detergent. After soaking it in the mixture for about an hour, remove and wash it with mild detergent and warm water. Rinse the brush afterward with water.
The final step in the cleaning process involves spinning. Using a spinner helps prolong the life of the brush by removing any loose traces of shellac and water on the brush’s bristles.
The spinner works by centrifugal force and also aids in keeping the bristles soft. You can also manually shake out excess liquid by whisking the brush. Once you’re done, wrap it in its holder and store it. You can dispose of the ammonia you’ve used on the lawn since it’s environmentally friendly.
Procedure for Using a Single Spray Gun to Switch Between Water-based Finish, Lacquer, and Shellac
You don’t have to purchase different spray guns for use with shellac, lacquer, or water-based finish. A single spray gun works just fine. All it takes is following the right cleaning procedure if you want to switch between the different finishes. This avoids mixups that can occur to ruin your paint job.
If you want to use your spray gun to spray shellac, first flush it with alcohol before spraying. After spraying, clean by flushing with alcohol. Switching to a solvent-based lacquer requires you to flush with lacquer thinner before spraying.
If you want to switch to a water-based finish, preflush it with lacquer thinner after using the solvent-based lacquer, then flush it with acetone or alcohol. Finally, rinse with water to prepare the spray gun for use with a water-based finish.
Do the reverse if you want to switch back to a solvent-based finish. Acetone and alcohol are miscible in solvent and water and aid in removing the residue left from the previous flush.
Tips on Thinning and Spraying Shellac
Spraying shellac is easier and faster than using a brush. However, it takes longer to build up a film thickness. It’s also convenient in that it produces an even smooth finish reducing the time required for sanding since it only needs a little sanding.
Mixing shellac fresh from flakes has advantages over buying premixed shellac, such as:
- Better moisture resistance.
- It’s easy to thin to the required best results.
- It gives you a wider choice of grades.
- It dries quickly.
Shellac flakes require dissolving with denatured alcohol. They are available by the pound and in different colors and grades. Dissolve using one pound cut. That means dissolving and mixing a pound of flakes into a gallon of alcohol.
Just like lacquer, shellac finish requires spraying thin layers. Shellac creates a high gloss finish. You can control the gloss level by the number of coats you spray on the surface. Three coats give you a matt finish. To get a satin-level gloss, you can stop at four coats. You can scuff down and add some coats to achieve a higher shine.
The first coat of shellac tends to raise the wood grain because of the alcohol. That’s why you need to sand the surface with 220 grit sandpaper. You can then use 320-400 grit sandpaper to lightly sand between the coats. Sanding removes the flaws so that they don’t compound over time and prevent the appearance of blemishes on the final finish. After spraying the required coats, you can reinforce the end product with 0000 steel wool.
You can use a shellac retarder when shellac dries fast. This can be due to low humidity or high temperatures. It also aids in easy flow-out and prevents the formation of an orange peel and over spraying.
There you have it: how to clean shellac out of your spray gun and brush. You can’t go wrong with using denatured alcohol and ammonia. For proper spray gun maintenance, the best practice would be to always clean your spray gun after using shellac instead of leaving it to harden.
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