Low Cost Spray Finishing Options
Inexpensive spray guns can be a very useful
addition to your primary finishing equipment.
Spray Finishing Overview Through the years I’ve become a big fan of spraying finishes on my woodturnings. Let’s face it, on medium and larger sized projects spraying the finish can be a real time saver. Most sprayed finishes have a smoother surface coat than a brushed or hand applied finish and as a result, require less buffing to perfect. The challenge for me has always been the additional labor necessary to set up and clean a large spray finishing system when I was working on smaller projects. After all, when you sell woodturnings for a living, you have to be able to justify the total time spent on each piece with the sales price.
In addition to the time and cost necessary to clean a large spray finishing system (gun, hoses, remote pot, filter, solvent for cleaning etc), there is also additional time required to store the unit away until it’s needed again. I don’t know about you, but cleaning a spray gun is not high on my list of fun things to do! It’s not hard to justify the clean-up time when you’re working on a large project or a big production run, but smaller projects are a different kettle of fish altogether…
It can easily take fifteen to twenty minutes to clean a large HVLP system and store it away properly. If you just want to shoot a small project though, that much cleanup time is tough to get your head around. So, I started experimenting with various small inexpensive spray finishing guns to see if they produced an acceptable finish coat, were easy to adjust and could be cleaned in two or three minutes tops. For a professional like me, time is money and that has a tendency to change your perspective when the bills start rolling in every month.
Spray Finishing: My Turbinaire HVLP System
I use my Turbinaire HVLP spray
system on medium and large projects.
(Turbine motor unit not shown).
I would be remiss not to mention my 3-stage, 5” diameter, variable speed Turbinaire HVLP spray finishing system (6PSI at 110CFM), Model #2235. When I’m working on medium and larger projects, it’s my system of choice and it allows me to achieve some incredible results with the plethora of finishes I use in my studio. It does require more clean-up time than the smaller guns I use, but its superior spray pattern and overall superb performance make up for any extra effort needed to clean the unit at the end of the day.
Spray Finishing: Detail/Touch-Up Spray Guns
While my Turbinaire HVLP (High Volume, Low Pressure) system excels at spraying a variety of materials, it’s overkill for smaller projects. For years, I used traditional aerosol spray cans of various finishes for these smaller projects, but the finishes available in aerosol cans are somewhat limited. Some finishing products are only available in quart or gallon cans and if you custom blend you finishes as much as I do, you really need to be able to spray these finishes as well.
I use this inexpensive mini-spray
gun for spraying solvents.
I’ve used numerous cheap spray guns over the years and never really liked any of them… Some worked well, but cost more than I really wanted to spend and others were a real pain to clean, or did not produce acceptable results. I wanted a gun that would work well for spray finishing small inexpensive projects like bowls, boxes and smaller hollow forms and would be relatively easy to clean. By easy, I mean quick, really, really quick.
I knew that I would be sacrificing some quality by using a dirt cheap, no-name knock-off spray gun, but that tasks I was going to use them for would only require an acceptable level of performance, not perfection. When you’re spraying sanding sealer, you’re not looking for perfect atomization' you just need to get the sealer onto the bare wood surface efficiently. The same holds true for spraying solvents, you do not need a $1,000.00 spray gun to spray lacquer thinner!
This generic mini spray gun produces
a very good atomized spray pattern.
I also wanted to be able to spray binary epoxies, which I have done for many years using a small airbrush and my larger HVLP system. Cost was another factor – the gun had to offer good adjustability, a decent atomized stream and be inexpensive as well. That way, I would not cringe when I had to occasionally pitch it into the rubbish bin after only a few uses. Spraying epoxy is a delicate dance with time and temperature and sooner or later, you come up short.
If you’re spraying epoxy and it begins to cross-link inside the gun, your gun will become a nice piece of multi-media sculpture art in short order. (Don’t ask me how I know this…) I use special protocols for spraying epoxy with my larger HVLP system, but they are too time-consuming for a small project. If the gun was cheap enough though and the epoxy cross-linked inside the gun, I could just pitch it and get another one.
I’ve tried numerous conventional mini spray guns and several HVLP mini spray guns as well and I finally settled on two that have been working well so far. These types of guns are sold under a lot of different names and are usually shown in the tool catalogs as a detail, or touch-up spray guns. Other manufacturers may have similar units that work as well or better, but I stick with these because they work well and fit within my idea of “consumable equipment.”
In-line moisture desiccant cartridges are
inexpensive and do a good job of removing
moisture from the air supply line.
I recommend you purchase an HVLP mini spray gun if possible, as it will produce less overspray and is more efficient at transferring the finish product onto your project surface. Better transfer efficiency means less overspray (less mess to clean up) and lower overall material costs per project. If you’re a hobby woodturner, you’re probably not interested in saving a few pence here and there when you shoot a finish, but when you’re shooting projects regularly, the cost savings offered by HVLP mini guns adds up quickly.
This mini HVLP spray gun is easy to
adjust a produces a fine atomized spray pattern.
My favorite low cost HVLP detail spray gun is the Harbor Freight model #46719-3VGA, it usually sells for $59.99, but if you watch the sales fliers (you can sign up for a free flier on the Harbor Freight website to be mailed to you each month), you can usually find it for less during a sale. This gun is relatively inexpensive and it is an HVLP gun, offering a minimum 65% transfer efficiency per the manufacturer. It consumes 3.7CFM and operates at 43PSI.
I also have a few other miscellaneous mini spray guns from various sources, all of them appear pretty much the same from the outside, so check around and buy on price. These are conventional spray guns, but they are dirt cheap and can usually be found for less than $25.00, even for as little as $10.00 when you catch a sale. Now at that price, I don’t really care of it clogs up every so often when I’m spraying epoxy, or if a collector shows up to visit or buy some of my work and there’s no time to clean the gun properly
This Kobalt mini spray gun
features an adjustable reservoir cup.
I’m also using a conventional mini spray gun from Kobalt. It is available at any Lowe’s hardware store in the pneumatic tools department. One advantage this gun has over the Harbor Freight gun is that the cup can be rotated to insure proper delivery of the finish at almost any spraying angle. This is a real bonus with many projects, as you can’t always spray with the gravity fed cup at an acceptable level of tilt to the surface of the project. It is easy to adjust, atomizes reasonably well and it can be cleaned very quickly.
By loosening this locking nut,
the reservoir cup on the Kobalt
mini spray gun can be rotated 360 degrees.
Remember, that with any of these low cost spray guns, you will not achieve the performance of high-end professional spray equipment. You pay for what you get and this holds true here as well. If your needs are demanding and you’re spraying frequently, then there are plenty of superbly made spray equipment and guns from which to choose. However, if you just want to shoot some sanding sealer, a solvent wash, a thin oil finish or perhaps a wash coat of shellac, then a low cost el-cheapo spray gun may serve your needs well enough for the occasional odd job in your studio.
Spray Finishing: Pressurized Refillable Spray Cans
This refillable sprayer can be
used with almost any thin viscosity finish.
http://sbi6.sitesell.com/cgi-bin/sbi/buildpage.pl?NEW=Add%20a%20SiteBuilder%20Page&AFF_CODE=109032&DOMAIN=woodturningvideosplus.com&SORT_TYPE=If your spray finishing requirements are not too demanding, a refillable spray finishing bottle might be sufficient for your needs. These are great products for spraying thin oils, solvents and sanding sealers. They are not expensive and it’s easy to keep a few around for various quick spray jobs that do not require a better gun, or your big bad HVLP system.
These are available from numerous sources, but I typically get mine from Harbor Freight Tools when I’m in the store. They cost about $20.00 each and at that price, you can afford to have several on hand for the odd spraying jobs that pop up from time to time. The only caveat with using them is that the finish must be thin enough to spray through the head, which means that you will need to measure and adjust your finishes for the proper viscosity using a Zahn cup, or a similar viscosity cup to insure a proper spray performance. Of course, you usually have to do this when spraying from a larger gun as well, unless the finish is water thin.
Spray Finishing: Airbrushes
Glass reservoirs like this make spray finishing
small projects with airbrushes a breeze.
Airbrushes are another great option for spraying small amounts of finishing products, patinas, colouring dyes, gloss enhancers, suspended micas and similar products. Although some of my airbrushes cost several hundred dollars each, I also have some that are relatively inexpensive that work very well for a variety of projects. I’ve even seen a few in the craft store that sell for less than $50.00 that should work for all but the most demanding of projects.
Most airbrush kits come with larger glass reservoirs that allow you to spray larger quantities of product without the need to constantly refill the small gravity or suction feed cups normally used with airbrushes. If you airbrush kit did not contain any auxiliary reservoirs, you can usually find universal ones that will fit your airbrush at any supplier that sells airbrush products.
Spray Finishing: Useful Options
Plastic viscosity cups are suitable for determining
the proper viscosity for most finishes
in a woodturner's studio.
Zahn Cup: If you’re going to spray finishes, you need to get yourself a viscosity gauge. They are sometimes sold as “Zahn” cups, but you can find them at any store that sells spray finish equipment. Zahn cups are an efflux viscometer-measuring device that consists of a small cup with a hole in the bottom. Zahn cups are used to measure the viscosity of liquids, by dipping the cup into a liquid and noting the time it takes for the cup to empty through the bottom hole. The total time required to empty the cup correlates to a specific viscosity on an accompanying chart. Unless you’re going into spray finishing big time, the plastic cups will probably be sufficient for your needs and are much less expensive than the certified metal cups.
Aerosol propellants are available
for use with any airbrush.
Pressurized Gas Supply for Airbrushes: If you want to play around with airbrushing, but you don’t have a small compressor you can purchase pressurized gas supply cans that allow you to use your airbrush without a compressor. These gas cans are not exactly inexpensive (~$9.00 each), but if you’re only going to use it a few times per year, it can be a lower cost option than purchasing a mini-compressor for your airbrush. I like to use these portable gas supply cans when I’m airbrushing on the back patio, since I can eliminate the compressor noise and there’s no electrical cord to manage. It’s also nice to get outside of the studio from time to time and enjoy the weather, whilst I’m finishing my smaller projects.
Solvent Recovery: If you need to use a solvent other than water to clean your spray gun, you should try to recover the solvent in a bucket of some type so you can reuse it again. I use ordinary 5-gallon paint buckets (you can get new ones at most paint or hardware stores) with a tight fitting lid. The solvent wash is sprayed into the bucket during cleaning and is allowed to settle. After a few days, the upper part of the solvent is relatively clear and can be used again for primary flushing; the heavier finish particles sink to the bottom of the bucket and can be removed if desired.
This saves you a significant amount of money when using petrochemical solvents that can easily cost $10.00 - $15.00 or more per gallon and the solvent can be reused many times until it becomes too dirty. I always use fresh solvent for the final gun wash and flush, to insure that no finish residue is left in/on the gun. This final wash is sprayed into the primary wash recycle bucket and is used the next time for primary cleaning and flushing.
This can gun handle can easily
connect to any standard aerosol spray can.
Can Gun: If you use a lot of aerosol finishes in your studio, you need to get a nifty little device called a Can Gun. It is basically a plastic handle that fits onto any standard aerosol spray can and it gives you a nice comfortable trigger and handle to hold whilst you’re spraying the finish. If you’re tired of pressing down on those tiny uncomfortable spray triggers on your aerosol cans, do yourself a favor and get a Can Gun. They are available at almost any hardware store and cost about $4.00 each. Your index finger will be much happier from now on…
Can gun handles eliminate tired index fingers
while spray finishing!
Proper Safety Equipment is Required for Spray Finishing: It should go without saying, but you must wear proper safety equipment when spraying finishes, including protective body suits (if necessary), full or half-mask respirators outfitted with the proper protective vapor cartridges and chemical resistant gloves suitable for the finish you are spraying. Consult the manufacturers MSDS sheets in the U.S. and COSHH sheets in the UK for any finish or solvent you plan to use and observe all safety and personal protection warnings and recommendations.
Don’t think that you can safely spray finishes without wearing the proper safety equipment. Atomized solvents and finishes can be extremely hazardous to your health, so gear up before spraying any finish! Your health is too important to take shortcuts when your personal safety is concerned. Spray safely!
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 a regular 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 monthly articles covering technical topics, or project based articles in each issue.
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