Inlaid Cocobolo bottle stopper
finished with spray lacquer using
my lacquer finish shortcut
Overview: I've always been a fan of deep and lustrous finishes. The kind of glossy surface that looks like it's a ten-foot deep pool of pure liquid. However, it takes a lot of effort to obtain such a deep and lustrous finish and I've always experimented with ways to build a multi-coat finish faster. My experiments were focused on ways to achieve the same quality of finish in less time, which is a difficult goal to achieve with any finish.
Some of my lacquer finishes have up to twenty, or twenty-five ultra light coats of lacquer. Even the simple lacquer finishes may have five to ten coats. Since each coat must be applied individually, it can take quite a bit of time to build the finish to a sufficient level. Lacquer is an easy finish to apply, since each successive coat bonds to the previous layer without the need for sanding, or abrading the surface.
That means you can spray another coat on the surface as soon as the previous coat has dried sufficiently. The time interval between successive applications of finish varies with ambient conditions. Temperature, relative humidity, dew point and air currents in the room, as well as the viscosity of the product (spray or brush on) and the retarder, all contribute to the drying time. In the past, if I wanted to apply a twenty-five-layer finish, it might take up to two days to apply, depending on ambient conditions.
If you reapply the lacquer finish too fast, it may run on you. Applying too thick a coat can also cause the lacquer to sag, or run towards the lower part of the turning. This means you get to either sand it back off, or use some lacquer thinner to wipe it off and start all over. To get a good lay down, you need the right ambient conditions, apply very light coats and wait until the lacquer has dried sufficiently before applying each successive coat.
Depending on conditions, you may be able to apply several coats of lacquer finish in short order, but trust me… When you have a rush order to fill that has to get on the FedEx truck the next morning, the conditions are never good. It's too cold, too hot, too humid, too windy, too dusty, or something else prevents you from finishing your "red-ball" rush order.
This was one of the reasons I started experimenting with finding a way to apply multiple coats of finish on a surface in the shortest time possible. My quest would prove both frustrating and rewarding, as experiments usually do. My compressed gas assisted lacquer finishing protocol is a way to shorten the time required before you can apply another coat of lacquer. It is not intended to change the rules we all live by when we spray or brush lacquer finishes. It's more of a helping hand that allows you to finish your project faster.
Lacquer Finish: Forced Air Delivery
One of the more promising experiments that I conducted involved the application of a low pressure forced air stream onto the wet lacquer surface. Initially, this was done with compressed air, but this proved less than ideal for several reasons. First, there was too much moisture in the air coming from the 80-gallon reserve tank. The air in Houston is so thick with humidity that you drink it more than breathe it sometimes, so you have to use moisture control devices to dry the compressed air to an acceptable level.
I use a two-part moisture control system that involves an inline separator near the tank and a screw on absorber near the tool (used when spray painting). This works quite well, but screw on disposable moisture absorbers are just too expensive to leave on the supply line all the time. There are inline specialty heater/driers you can buy to dry and filter the compressed air supply, but they will redefine your idea of the word "expensive."
Obviously, you need dry air if you will be spraying it over a freshly lacquered surface. When I used my two part system, the air was nice and dry and produced good results, but they were still short of ideal. Another challenge with compressed air is oil residue in the air. This can be separated by a filter, but most of the in-line filters only do a fair job of removing atomized oil. If you want to really remove the oil, you'll need another expensive filter.
If you do not remove all of the atomized oil from the air, you can get surface defects in the lacquer finish called "fisheyes." Fisheyes are small circular depressions in the lacquer film. Surface contamination with silicone can also cause fisheyes. For these reasons and others, I needed to look for another option. Something that could be used "if and when" it was needed, even if I only wanted to spray a single bottle stopper, or a writing pen. It had to be fast, easy and preferably inexpensive.
Lacquer Finish: Compressed Gas Solution
Although I could make the air from my compressor work with some expensive add-on accessories, the expense and maintenance issues were not appealing. I could also use the heated air from my HVLP spray rig if necessary, but I wanted something that was simple, involved no setup or cleanup and was ready to go when needed.
I started experimenting with various compressed gases and finally settled on a product sold as "Dust Remover," a compressed 1,1-difluoroethane gas sold to remove dust and lint from surfaces, electronics and other things. Using compressed gas eliminated many of the potential problems (moisture, oil, other contaminants etc.) with using compressed air from the air compressor.
The dust remover gas has performed superbly and I have been using it for the last few years to speed up the interval between my lacquer finish applications. In the past, it may have taken forty-five minutes or more to apply 10 – 12 coats of lacquer, depending on ambient conditions. Using my compressed gas protocol, I can now apply 10 - 12 light coats of spray lacquer on a small project in about twenty minutes give or take. That's a 50% reduction in application time! You might be able to go even faster, but I'm satisfied with my current speed and finish results.
3M's dust remover is used for my compressed gas lacquer finish application protocol
Of course, I still have to wait for the lacquer to set up before buffing, (overnight, or up to two days) but this application protocol has allowed me to significantly speed up my finishing process. This is very valuable option if you are trying to finish multiple copies of a project. Another benefit of quickly setting the lacquer is dust control. Once the lacquer is tack free, dust will not stick to it as it continues to cure. This is a great benefit if you are continuing to work in the area on other projects.
Caveats to Using Compressed Gas on a Lacquer Finish
Note: Lacquer should only be sprayed in properly certified spray booths, or in areas with sufficient fresh air supply - while you're wearing a full-face respirator with the proper vapor cartridges installed. Please follow all manufacturer safety precautions and wear all protective equipment that may be required when working with, spraying, or brushing lacquer.
This protocol has been a significant time saver in my studio. It has allowed me to rapidly apply multiple coats of lacquer on finished pieces much faster than spraying the lacquer and waiting for it to dry in the open air before reapplication. However, there are a few caveats to using this protocol:
This protocol also works to speed the drying of metal leaf adhesive
You can also use this protocol with spray spar urethane
Compressed Gas Assisted Lacquer Finish Application Protocol
Lacquer sanding sealer is used to seal the bare wood surface before applying the lacquer
Here is the protocol I use for speeding up the interval between applications of spray lacquer:
Lightly spray a coat of lacquer on the surface of the project - If the project is mounted on the lathe, rotate the spindle by hand as you apply the lacquer. If the project is not on the lathe, use a Lazy Susan turntable, or an electric rotating presentation table when spraying lacquer.
Using Master's Magic spray lacquer to finish
a Cocobolo inlaid bottle stopper
Immediately after the applying the lacquer, lightly spray the compressed gas across the surface of the project as you rotate it by hand. I usually keep the tip of my applicator about four to six inches away from the surface and only pull the trigger a tiny bit to get a light flow of gas.
Using 3M's dust remover to speed the
drying of lacquer between coats
Lacquer Finish: Final Thoughts
This protocol has been a real timesaver for me and I have used it extensively for the last few years when working with spray lacquer. I have also used it when working with other finishing products as well like spirit stains, spray shellac, spray adhesives for metal leaf, paste waxes and other products. While you may not think you need to speed up your finishing now, this is another protocol that you can keep in mind for the time when you do need it.
Spray shellac is another finish that can be used with this shortcut protocol
Try this protocol the next time you use Krylon's spray acrylic finish
If you want to give this protocol a go, practice on scrap wood first! This protocol requires finesse and a light touch. Practicing on scrap wood makes sense and will allow you to hone your application skills on inexpensive wood. When you have developed the right "touch", try it on one of your regular projects. I think you'll find it as useful as I do. Good luck!
Safety Note: Always follow all manufacturers safety instructions before working with your lathe, or any of the tools or products you may use. If you are unsure about any operation, obtain competent professional instruction before proceeding. Use and wear all necessary safety devices during turning and observe safe woodturning practices to prevent accident or injury.
Steven D. Russell is a professional studio woodturner, teacher and writer. He has written numerous articles for international woodturning magazines, which have been published in more than 78 countries around the world. Steve has demonstrated in numerous cities across the United States. His studio, Eurowood Werks, specializes in bowls, platters and hollow forms with unique visual and tactile treatments.
Steve is also the current and founding President of the Lone Star Woodturners Association, Inc; an AAW member chapter. The LSWA is a 501(c)3 non-profit educational organization dedicated to teaching and demonstrating the art and craft of woodturning.
Steve is also a featured writer for the Guild of Master Craftsman's "Woodturning" magazine, published in London England. Woodturning magazine is the world's leading magazine for woodturners. Look for his articles covering technical topics, or project based articles in an upcoming issue.