Canvas varnish – Spray coating

The Star-Lac varnish can be used in several ways for coating the prints, as followed: spraying through air gun, a roller or through a liquid varnishing machine with heating system.

I recommend doing the spraying in a room and not outside a building or in the open air, since the canvas print’s wet varnish layer might be exposed to dust, dirt or flying insects.

Also, make sure the place is being ventilated by placing a fan that pumps the air from the room to the outdoors.

Take a cardboard surface on which the print canvas be glued with masking tape.

Also, one must use a gas mask. I recommend purchasing a professional good gas mask, and the only thing left to do is to replace the filters every few months.

Before using the Star-Lac varnish, mix the liquid inside the gallon and for that purpose turn over the gallon from side to side several times.

After pouring the Star-Lac varnish into the spray gun container, place the cardboard surface on a pedestal higher from the floor with a little backward gradient.

It is important that the canvas print would not be close to the floor, so that dust would not rise and fly as a result to the air pressure.

Before spraying, I recommend to learn how to use your spray gun and aim the amount of liquid coming out of the spray guns and the air pressure, through aiming the gun’s valves  I recommend using a high air pressure in the spray gun and the spray opening angle to be as broad as possible, also one has to aim the amount of liquid outgoing from the nozzle to be little one and the flow not to be strong, in order for the spray gun not to emit some kind of “spittings” or drops all over the canvas print.

If you are not sure with your experience, you can use colored water over the canvas surface at your first attempt and when you feel you are ready, you can use the varnish liquid.

The spraying is done using the wrap and weft weaving method. The first direction is from right to left and the second one is from top to bottom. It is preferable not to move too fast allowing the liquid to be absorbed across the canvas, however moving too slowly is not recommended, since leaks might be created.

Basically, the speed and technique of the spraying shall be shaped after accumulating the required skill.

Pay attention to the fact that at each the spraying direction, one must change the spraying head’s direction in the air gun, so that no strips and leaks would be created.

Hold the spraying gun in about 8 inches distance from the canvas print and do it during making overlap of fifty percent between the heights degrees.

You might not notice the coating layer in certain situations such as, very hot weather, a situation in which the canvas quickly absorbs the lacquer or one in which the liquid amount coming out of the nozzle is too little, so it is doable to spray in an additional direction, that is to spray in the wrap and weft weaving method three times.

After finishing the first layer, wait for the varnish to dry, the drying duration depends on the air humidity and the heat, more heat would dry the varnish, while coldness would cause the varnish dry slower.

(I personally love the hot summer days, since in this season the lacquer immediately dries within minutes. (

It is very important to place the canvas print for drying outside the spraying room and it is better to post the cardboard on a ready made facility.

Place the cardboard horizontally and not vertically to prevent leaks of the varnish liquid.

After the first lacquer layer dries, the canvas print will be protected from moisture, UV rays, fading, in addition to much more benefits, as described on our website. After this, the canvas print is ready to stretch over a wooden frame.

For those of you who want to provide the canvas print with extra protection and additional flexibility, or for it to resist bad weather, perform a second varnish layer.

The second layer has to be performed after the canvas print completely dries out, and that, of course, depends on the temperature.

One can speed up the drying process by exposing the print to a heat source like a room heated by air-conditioner or even by using a hairdryer.

After the spraying stage, return the amount left in the spraying tank back into the plastic gallon and then well rinse with water the spraying gun and spray for a few seconds to get rid of the remained varnish liquid in the spraying gun, or press the trigger for half a minute in order to let the water rinse out the remnants of the varnish liquid.

Also, from time to time, when the spraying gun does not perform a good coating and varnish, open the spraying gun and soak its metal parts in a vessel of boiling water and then brush them to clean the passages of the spraying gun.

It is important to keep the air apertures open in order to get a smooth and homogenous distribution of the varnish, therefore I recommend using a very mild needle or even a thin fishing wire and pass it inside the holes to make sure they are open.

Another important thing you must do in your next use with the varnish liquid is – with the remains you have returned from the spraying tank to the Star-Lac gallon – to filter it before spraying the following coatings, since a material crystallization can be created inside the spraying gun or entering of dust or dirt that got in by mistake. Therefore, filter the varnish liquid before spraying, that is in the following pouring from the Star-Lac gallon into the gun spraying tank. It can be simply made by placing a thin filter, like a pantyhose fabric or a metal filter. Then wash the filter with water and it will serve you next time. You can get different finishes of the Star-Lac lacquer such as: gloss, satin, or matte.

We are sure you will enjoy the benefits of the Star-Lac canvas varnish and you can also offer your customers a high quality finished product, which will make them appreciate your work and the product and return to you again and again with every canvas print job they need.