I so much enjoy the opportunity to read and review the monthly articles that our guest writers present to us. I must admit that it often triggers a subject that I can address in my message to you.
This month Carl Duguay shares his views with us on the importance of finishing and as an inclusive part of woodworking and not an afterthought to other aspects of project development.
When teaching about finishing my opening comment is usually: “Your work is often judged on how it looks and feels…” “This is why you need to learn everything you can about the finishing process.”
Once your project is built and completed you need to focus on preparing your work for the finishing process. It’s important to know about sanding, sanding products and the best methods to complete this process. The actual finish application process will never hide poor preparation. There are good books on this subject and Carl recommends a few.
It’s important to learn how different woods act and interact with stains, coatings and finishes. It’s good to know about different types of finishes and which are best for your project.
Next is to learn about application methods. Are you going to be applying your finish manually or by spraying? Again, learning all you can about each method will help you develop the skill necessary to complete your project.
Just as you have probably researched and purchased the best tools to build your project, I strongly urge you not to cut corners on a most important part of your project.
You can find so much information in previous newsletters. There are all kind of tips and articles from experts. Use the search function for specifics, or spend some time reading previous articles and tips.
To repeat my earlier message: “Your work is often judged on how it looks and feels.” Your project deserves the best. Learn all you can and purchase the best quality finishes and tools to complete the job.
Visit www.thefinishingstore.com to see a range of products to help you achieve “The Perfect Finish.”
Sr. Vice President, Sales & Marketing
Apollo Sprayers International, Inc
Finishing Feature Article: First Steps in Finishing for Novice Woodworkers or Master Woodworkers
by Carl Duguay
It's probably realistic to think that when people take up the craft of woodworking they quite naturally focus of the front end - what equipment and tools they need to process the lumber, cut the joinery, and assemble their projects. Finishing is likely to be an afterthought.
I've always encouraged new woodworkers to think of finishing as an integral part of the woodworking process, rather than something tacked onto the end. For example, the wood you select for a project will influence the type of finish you choose, and both these choices will have a distinct impact on what the finished product looks like. Likewise, the care and attention taken in preparing the wood (and in particular, sanding) will go a long way towards making a more successful finish. And, it's often easier, and more efficient, to apply the finish before assembly, particularly with parts that will be less accessible after everything has been put together.
It's doubtful anyone would consider using dovetails on a project without first practicing the technique for some period of time. The same concept applies to finishing. Fortunately, you'll acquire proficiency in applying a quality finish much more quickly than you will cutting perfect dovetails.
Novice woodworkers can avoid a great deal of aggravation by trying out several of the more common finishes before committing to their first project. It's the only way to get a real feeling for what it's like to apply different finishes and to gain experience in the various application techniques. I suggest starting with oil, varnish, and water-based finishes, and avoiding pore filling, staining, French polishing, and spray finishing until you've acquired a basic level of proficiency with the more commonly used finishes.
Getting started in wood finishing isn't overly expensive, and it doesn't require a huge investment in time. Here are the basic tools and accessories I recommend to my students.
The first step in obtaining a great finish is understanding the material you're working with in it's various forms - raw wood, sheet goods, and veneers - and the tools and techniques for applying your chosen finish to this material. Fortunately, you don't have to discover all this yourself. You can benefit from the experience and advice of those who've done the research, made the mistakes, and learned the lessons on the nature of wood, and how best to choose and apply finishes.
By far, the best book I've read on understanding the idiosyncrasies of wood is appropriately titled "Understanding Wood" (R. Bruce Hoadley, ISBN: 978-1561583584). This book contains just about everything you'll ever need to know the nature of wood, why and how it moves, what effects wood movement is likely to have on what you build, and how to compensate for this unavoidable movement.
There are quite a few finishing books on the market, and all of them will have some useful information. The book that has been my 'go-to' reference for the past two decades is Bob Flexner's "Understanding Wood Finishing" (ISBN: 978-1565235489). For about $25 it's the next best thing to having Bob sitting beside you in the shop. This book provides the clearest, most comprehensive, practical treatment on the subject that you're likely to find.
In woodworking, when an accident happens it typically has an immediate impact. Not so with finishing. Dust, fumes, and chemicals can take years before their insidious effects begin to show. You need to have, and use, both particulate filters (disposable dust masks) and a cartridge respirator. A dust mask will provide protection from shop dust and some fumes, but not gases or vapors. Any of the popular brands that have an N95 rating will do. I find the 3M 8511 works well because its exhalation valve keeps the face dry and makes breathing easier.
A respirator contains special carbon filtering material that absorbs gases and vapors. The one I use is a half-mask 3M 7500. It's very light weight, comfortable to wear, and is compatible with a wide range of filters. Disposable vinyl gloves are also handy when it comes to applying stains and finishes.
Good surface preparation is a key to obtaining a stellar finish. Milling marks, fine scratches, and thin slivers of dried glue that may be barely visible prior to finishing will stand out like a sore thumb after the finish is applied. The sanding sheets and disc brands that I particularly like are Norton’s No-Fil Adalox Aluminum Oxide and the Mirka Royal brand. Both of these stearated papers are flexible yet tough, cut quickly, don't clog up too much, and are reasonably long lasting.
For power sanding nothing beats a variable speed random orbital sander (ROS). Use one that comes with a dust bag or that can be connected to a dust extractor. These sanders have an offset drive bearing that causes the sanding pad to move in an elliptical orbit, which reduces scratching against the grain. You can move the sander any direction on the wood: with the grain, diagonal to the grain, and even against the grain. I use the Bosch 3727DVS, which takes the more common 5" sanding discs, and also 6" discs, which make quicker work of sanding large panels.
For both hand and power sanding the most frequently used grits are 150, 180, 220, and 320. Finer grits are best used for rubbing out fine finishes. It's much more economical to purchase the four basic grit sizes in boxes of 100.
Card scrapers are also a useful and relatively inexpensive tool to have on hand. They're handy for quickly removing mill marks, dealing with minor tear-out, and working on narrow stock where sandpaper would round over edges. You'll eventually need to acquire the tools to maintain a scraper - a single cut file and a benchstone. For a burnisher you can use a 1/4" steel rod.
Rags are indispensible for wiping on polymerized oil or varnish/mineral spirit finishes, fillers, and stains, and for cleaning chores. Any cotton fabric will do as long as it's lint-free. I purchase used T-shirts and bed sheets from the local thrift shop. After using a rag you'll want to hang it over the edge of a garbage can until it dries, and then toss it out.
For rubbing out a finish and applying a paste wax you'll need some fine strand (choose the 0000 grade) oil-free steel wool (or a synthetic product like the 3M superfine rubbing pad). It holds up well and is longer lasting than the ordinary steel wool found at building centers and home hardware stores. Rubbing out with steel wool produces a smooth satin sheen. Once you're comfortable with this, you can move on to various rubbing compounds to get a higher sheen.
For applying varnish and water-based finishes two brushes will suffice - a 2" wide, flagged end, chisel shaped hog bristle brush for varnish, and an equivalent 2" synthetic brush for water-based. 2" foam brushes are also effective for laying down water-based finishes. A can of mineral spirits will do for cleaning the varnish brush, and for thinning varnish.
All that's left is to purchase a few different finishes and begin practicing. It's easiest to start with a wipe-on oil/varnish finish, and then move on to varnish and water-based finishes. There are a number of equally good brands on the market, including General Finishes, Safecoat, Varathane (Fletco), Target, and Minwax, with quart containers being the optimal size to purchase.
I think most people will be pleasantly surprised at how quickly they can produce a great finish. As with just about every aspect of woodworking, the key to success is practice.
Products of the Month: Essentials for Every Woodworker, Novice or Master Woodworker
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Each AquaGlide brush is individually handmade with detail to quality. This 100% SRT nylon brush is dyed, tipped and flagged for maximum paint pick-up and release with minimal streaking. It is formulated for use with all paints.
For more than 18 years, Bob Flexner has been inspiring woodworkers with his writings and teachings on wood finishing. Now, from this best‐selling author comes the long‐awaited and completely updated second edition of “Understanding Wood Finishing” – the most practical, comprehensive book on finishing ever published.
MSA Paint & Pesticides Respirator with Extra Cartridge and Pre-filter
Don’t waste your money on cheap inexpensive respiration. This is your health and you want only the best paint overspray and dust protection.
Finishing Tip by Bob Flexner: UV-Cured Finishing
One of the fastest-growing areas of wood finishing is comprised of finishes that cure when exposed to ultra-violet light. The UV light causes these finishes to crosslink and cure almost instantly. This class of finish has a number of advantages over more traditional finishes, including almost total elimination of VOCs, less waste, less floor space required, immediate handling and stacking (so there’s no need for drying racks), reduced labor costs and faster production rates.
The two most important disadvantages are the high initial cost for the equipment and difficulty finishing complex three-dimensional objects because the UV lamp has to be placed at a fixed distance and perpendicular to the surface.
So getting into UV-cured finishing is usually limited to larger shops making fairly flat objects such as doors, paneling, flooring, trim and ready-to-assemble parts.
But the technology is advancing rapidly, so you may want to keep an eye on the progress. The trade association is RadTech International (www.radtech.org).
If you’re interested in learning more, Lawrence C. Van Iseghem, president of Van Technologies in Duluth, Minn., has written a great introductory article, “Wood Finishing with UV Curable Coatings” which you can find by searching for the title online.
Also, the State University of New York has archived more than a dozen informative webinars dealing with UV-LED curing at www.esf.edu/outreach/uvebwebinar.
Finishing Tip by Bob Flexner: Pressmarks
A pressmark occurs when an object is placed on a finish that hasn’t fully hardened. An example is shown in the accompanying picture.
Pressmarks can occur with any finish but are most likely with film-building finishes. Of these, shellac and all types of solvent lacquer except brushing lacquer dry the fastest. Water-based finish is next in drying speed. Slowest are the various types of oil-based varnish, including polyurethane varnish.
Varnish and brushing lacquer should be allowed to dry overnight, sometimes longer, before placing a heavy object on them. Weather conditions, especially temperature, will cause a difference in drying speed. All finishes dry and harden slower in cooler temperatures.
A common situation in which pressmarks can occur is in production shops where panels or doors are finished, then stacked. If there aren’t drying ovens, drying racks should be used, and the panels should be allowed to dry for at least several hours to overnight before stacking.
Finishing Tip by Bob Flexner:Brush Marks
Brush marks, as shown on the left side of the accompanying picture, are the result of brushing a finish that is too thick (viscous), not formulated to level well, or both. It’s not the quality of the brush that is at fault as is so often claimed.
Finishes are formulated differently, and some level better than others. Even so, brush marks can still happen if the finish is too thick. Keep in mind that all finishes thicken in cooler temperatures.
So the obvious way to eliminate brush marks is to thin the finish with the appropriate thinner. The more you thin the finish the less likely you’ll get brush marks. But the thinner each coat, the more likely you’ll have to apply additional coats to achieve the build you want.
A trick you can use to get a thicker build quickly is to apply several coats full strength, let them dry, then sand level and apply several thinned coats. The right side of the accompanying picture shows the same finish as on the left with no brush marks because it was thinned before brushing.