Finishing Isn't an Afterthought | Canadian Woodworking & Home Improvement

For novice woodworkers, learning about wood finishes and how to apply them is just as important as developing wood processing and joinery skills.

Finishing Isn't an Afterthought

Finishing Isn't an Afterthought



Photos by Rob Brown

It's probably realistic to think that when people take up the craft of woodworking they quite naturally focus on 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 of these choices will have a distinct impact on what the finished product will look 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.

Practice first

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 cutting perfect dovetails.

When practicing applying a finish, sand a piece of wood as you would when preparing to finish a project. Next, apply the finish to that panel. Apply the finish following the manufacturers instructions, and always allow adequate dry time between coats. If this is also so you can see how a specific finish will look on a specific species of wood, you might want to try out a few different species of wood, as most finishes look different on different species. It might even be a good idea to label all of these panels and keep them in your shop so when you're selecting a species and finish later on you can have a good idea of what the final look will be.

Keep things simple

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 a penetrating oil finish and avoiding film finishes, pore filling, staining, French polishing and spray finishing until you've acquired a basic level of proficiency with the more commonly used finishes.

Hardwax oil finishes, like Rubio Monocoat's RMC Oil Plus 2C (RubioShop.ca) are particularly easy to apply, and they provide excellent surface protection. The Rubio finish is especially practical because it only contains plant oils, waxes, non-aromatic hydrocarbons, lead-free catalytic dryers and organic pigments. It's also VOC (Volatile Organic Compound)-free, and available in over 40 colours.
 
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.

Books

The first step in obtaining a great finish is understanding the material you're working with in its various forms – raw wood, sheet goods, and veneers – and the tools and techniques for applying your chosen finish onto 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 about 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 much of the past three 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.

Personal protection

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, a good fitting cartridge respirator. Any of the popular brands that have at least an N95 rating will do. I use a 3M half mask respirator (#7500) with a P95 cartridge (#6001) rated for organic vapour. It's very light weight and comfortable to wear.

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Protect Yourself – You only get one set of lungs, so be sure to protect them from damaging fumes. Although it might not be necessary if you're wiping a finish on a small project, it never hurts to keep your lungs as healthy as possible. (Photo by 3M)

Surface preparation

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 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 sanding discs, I almost exclusively use net-back abrasives, like Diablo's SandNet or Mirka's Abranet. The entire surface of these discs is peppered with hundreds of tiny holes making it easy for dust-laden air to pass through. This results in little dust getting into the air you breathe, the discs don’t clog up with dust like standard discs, and you get less dust contamination on your work surface (DiabloTools.com, Mirka.com, NortonAbrasives.com).

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. There are many great models available in stores though.

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Work Smart, Not Hard – Sanding disks are available in many grits, and will help take a lot of the grunt work out of the critical stage of sanding.

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, a benchstone and a burnisher. For a burnisher you can use a 1/4" steel rod, as long as it's harder than the scraper.

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Card Scrapers – A sharp card scraper can make quick work of removing milling marks, and put you on the path of ensuring wood is ready to accept a finish.

Application gear

Rags are indispensable for wiping on polymerized oil or varnish/mineral spirit finishes, fillers and stains, as well as 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. Spontaneous combustion is a serious workshop hazard when it comes to dealing with many finishes.

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Careful of Used Rags – A cost effective way to apply many finishes, oil-soaked rags can spontaneously combust if not disposed of properly.

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.

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Finishing a Finish – When used with some furniture wax, #0000 steel wood and superfine 3M abrasive pads will go a long way to helping you achieve a finish that's smooth to the touch. Sadly, they won't be a cure-all for a poorly applied finish though.

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 and very reasonably priced for when it's time to lay 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 Hardwax oil or wipe-on oil/varnish finish, and then move on to varnish and water-based finishes. There are a number of good brands on the market, including Rubio, General Finishes, Livos, Minwax, OSMO, Saicos, Target and Varathane, with quart containers being the optimal size for most new woodworkers 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.


Carl Duguay 2

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