Posted on October 9th, 2013 No comments
A common situation in furniture restoration is matching a newly made part to the color of the rest of the object. Water-soluble dyes are much more effective for doing this than commercial store-bought stains.
The water-soluble dyes I’m referring to are those made by WD Lockwood. They are also sold by Woodworker’s Supply under the name Moser.
Metalized dyes like those sold as NGR stains or Transtint aren’t nearly as effective because they are difficult to lighten. Trying to tweak the color usually results in it getting darker as the two colors blend and there’s no easy way to lighten it.
The water-soluble dyes from Lockwood, which are sold as powders for you to dissolve yourself, are easy to lighten simply by wiping with a wet cloth after the dye has dried. They are also easy to tweak or even change the color entirely, as shown in the accompanying picture.
On this panel I stained the entire surface with the red dye shown in the middle section. Then I wiped the left section with a yellow dye and changed the color to orange. I wiped the right section with a black dye and changed the color to brown. This sample shows an extreme example of how much control you have of the color.
The usual way to match the color of a new part is to practice on scrap wood of the same species until you get it right. Then apply the color to the part. But if you’ve tried this you know that it rarely works to your satisfaction. Somehow, the color that seemed good on the scrap often looks wrong on the new part.
With water-soluble dyes you can practice right on the part. Go ahead and glue it into the furniture, then apply a dye color you think is close to a match. Because the color you’re going to get with the finish applied is the same as the color of the part with the dye still damp, you can see right away what adjustment you need to make. It’s usually adding a little red to warm the color, a little green to cool the color, or a very little black to dull the color.
A big advantage of using a water-soluble dye is that you don’t have to worry about damaging an adjoining finish if you get some of the dye on it. Just wipe it off.
Posted on October 9th, 2013 No comments
Last month we featured an article by extraordinary woodworker, Charles Neil, showing how to create antique finishes. Below is the second part of the article. Before reading the article, take a look at Charles’s latest project, a gorgeous coffee table made from “junk wood.” It looks so far from being “junk” and is really a stunning piece of sculpture. We love the “bird’s nest” below the table.
Charles loves to experiment with finishes, and use his knowledge to play with techniques, wood and coatings. We can all learn from his ideas. Here are some great tips from a great finisher:
This is a piece of 8/4 cherry just to show the technique. I like to take a power carver or carving chisel and “bark” the edges of slabs and so forth. Then give it a light coat of finish and glaze it dark, it gives it that “hewn, barky look,” and it’s really nice if you’re into slabs and so forth as you can sort of free form it the way you want and get a nice complimentary edge treatment.
Here is a piece of tiger maple I jigsawed to a “natural form” and then used the same technique.
This is a piece of tiger maple that I oxidized. The brown was done with a mixture of vinegar and steel wool let soak for a day or so. The more steel wool and the longer you let it soak the more intense the color will be.
The bluish/steel look is done with Ferrous Sulfate, which is an iron supplement you can get at any drug store, just dissolve 5 or 6 tablets in a pint of water and you’re good to go. In both cases it’s a reaction with the tannins in the wood.
However, not all woods have sufficient tannins to react, but we can cure that. Boil some green tea bags, (the real stuff) and make it really strong. I usually use about 3 or 4 bags to the pint, and apply and let dry before applying the vinegar or Ferrous sulfate. The tea adds tannins to the wood; I have also heard that strong black tea will do the same thing.
This is a piece of yellow pine that has been wire brushed with the grain then given the green tea and the vinegar solution).
This is the same yellow pine with the tea and Ferrous Sulfate. You will note in both cases how the strength of the tea, as well as the solutions, affect the color. The nice thing about the techniques here is that they are safe, nonflammable and can be enjoyed and used in either the home shop or at work.
Posted on August 6th, 2013 No comments
The principle differences between nitrocellulose lacquer and shellac are ease of application and their ability to block off problems in the wood. Both finishes are evaporative finishes, meaning that they dry entirely by solvent evaporation; there is no crosslinking as there is with varnish and catalyzed finishes.
As a result, both lacquer and shellac are more vulnerable to being damaged by coarse or sharp objects, heat, solvents, acids and alkalis. Shellac is more vulnerable than lacquer to being damaged by alcohol spills, of course, but keep in mind that beer, wine and mixed drinks are usually very watered down, so the vulnerability is much less than a straight alcohol spill.
Lacquer is much more user friendly than shellac because of the difference between thinners. Lacquer thinner is made up of a number of different solvents (usually about six, except in areas with strict VOC rules) that evaporate at different rates. This allows finishers to control the drying rate of the finish to avoid blushing, and runs and sags. With the right lacquer thinner, lacquer can even be applied successfully in cold temperatures. We have almost no control of the drying rate of shellac with just alcohol as the solvent.
But shellac has the advantage of being able to block off problems in the wood, such as silicone, which causes fish eye, various other oils, resin in oily woods, wax, etc. Shellac, therefore, can be useful as a sealer coat if you have one of these problems. For the most part, shellac is a great tool for refinishers who often encounter silicone problems, but of almost no advantage for finishing new wood.
The greater user friendliness of lacquer was the principle reason lacquer replaced shellac as a finish in the 1920s.
Posted on August 6th, 2013 No comments
Many, probably most, store-bought stains are made with both dye and pigment. If wood stained with these stains is exposed to sunlight or fluorescent light for a while, the dye color will fade away, but the pigment color will remain. The effect is that the stained wood changes color.
In the accompanying picture the red dye in this “cherry” stain has faded on the top half (I covered the bottom half) after only a few days in direct sunlight, leaving the color significantly different. It’s definitely no longer cherry color.
The fading occurs much more rapidly in direct sunlight than indoors with a window providing a partial barrier to UV light. Nevertheless, you need to be aware of the problem when choosing a stain, depending on where the object will be placed.
To my knowledge manufacturers never tell us if there is dye in the stain, so we have to determine this ourselves. The easy way is to open the can after it has sat on a shelf for a week or two to allow the pigment to settle, then insert a light-colored wood stirring stick an inch or so into the stain. If it colors the stirring stick, there is dye in the stain because dye dissolves; it doesn’t settle.
If you insert the stirring stick to the bottom of the can, and the pigment has fully settled, you should be able to bring up a little pigment. Very few stains contain no pigment, but some do.
With shellac and lacquer finishes, which are the finishes used on almost all old furniture and woodwork, you can use their solvent for stripping instead of a paint-and-varnish remover. Depending on the object being stripped, I often find this method easier in the sense of spending less total time. It’s also less messy.
Use denatured alcohol for shellac and lacquer thinner for lacquer. You can test the finish to find out which it is by dabbing a little of each solvent onto the finish. The alcohol will soften shellac and make it sticky or remove it. Lacquer thinner will do the same to lacquer.
Spread some paper towels (or cotton rags) over the surface and pour on the appropriate solvent to thoroughly wet the towels. Keep wet for 10 or 20 minutes, or until you can wipe off all the finish quickly and easily. If you have done a good job, a quick wipe with a towel or rag soaked with the solvent will clean up any remaining finish residue.
One advantage of using this method of stripping is that you don’t have to mess with removing the wax that is included in many strippers to slow their evaporation. This wax causes many refinishing problems, because people often don’t get enough of it removed.
Sprayer selection for finishing projects is really a simple matter, which has only become complicated by the fantasy of having one type of tool technology that can do it all. This dream doesn’t just apply to sprayers, but all tool types in general. Everyone wants to find the one tool that can “do it all”. It’s a nice thought, but really doesn’t coincide with the realities of finishing.
Because I deal mostly in the realm of professional paint contracting, I see a lot of cases where people try to drag that dream into existence by misusing that archaic weapon of mass atomization called the airless sprayer. If a painter has just one sprayer, it is most likely an airless pump, and they try to do everything with it. There was a time when you just about could, but that time has passed.
In the past decade, paint products have changed dramatically. Because of heightened VOC regulations, we have all witnessed the long drawn out swing of the formulation pendulum back around to waterborne finishes, and away from oil/solvent based products. As a result, the fine finish limitations of the airless sprayer have become glaringly apparent in the realm of fine finishing. This time around, the waterborne finishes are really good, viable replacements for oil. They are here to stay, which leaves many a finisher struggling with the failure of applying outdated tools and processes to new finish technologies.
Specifically, painters have an odd tendency to spray .5 gpm (or higher) sprayers wide open at 3300 psi (or more) on interior ceilings and walls, or even exterior facades, in production mode. This has long been a benchmark or “standard” for spraying, because it produces results on large, open road tasks. But then, there is the odd desire to turn right around, put a “fine finish” tip on the same airless machine and want so badly to believe in a magical transformation into a cabinet grade finishing sprayer.
What Happens When you put a Fine Finish Tip on an Airless Sprayer?
It would be nice, but real life doesn’t really work that way, and neither do sprayers. The old “airless with fine finish tip” trick kind of worked ten years ago when products were different. Oil trim paints were thinner, stayed wet longer and could be run through airless sprayers at reduced enough fluid pressures to do small tasks fast and get out of the space before the overspray/airborne mist gremlins set in to compromise the finish. Oils were thinner and easier to spray. With the new generation of waterborne finishes, a fine finish tip on a low transfer efficiency gun tied to a large pump results in neither efficiency nor high quality finishes.
It is the nature of the airless sprayer to require high fluid pressures, and to “shear” the material, resulting in a coarse atomization in comparison to the finer fluid droplets delivered by HVLP turbine units. This directly impacts the way products “lay down.” Add a roomful of airborne mist settling into the wet finish, and airless results become even more coarse. My own professional observation has been that the smaller the orifice of the “fine finish” tip on an airless sprayer, the more the fluid is sheared during atomization. This just doesn’t result in a fine finish on any type of scale, because latex doesn’t shear well. At least not well enough to meet generally accepted fine finishing standards.
The bottom line on the airless/fine finish tip myth is that painters who attempt cabinet grade finishes with this set up are for the most part plagued by inefficiency and overspray due to the poor atomization that results in airborne mist settling in the wet finish as it attempts to lay down, in turn yielding a less than smooth finish.
In fact, the larger the fine finish project, the worse the result usually gets when running an inefficient technology. And, of course, the act of just setting up a typical airless requires about a gallon of paint just to fill up the 50’ of hose and the piston pump.
Get More Quality “Bang” Out of a Bucket of Finish
As noted above, with the paint industry shift to waterborne finishes, my paint company has adapted its small scale fine finish program around HVLP, for a number of reasons. While waterborne finishes require high fluid pressure to pass through a small orifice in an airless machine, they happen to respond very well to high velocity and lower pressure (HVLP) spraying.
In very simple and practical terms, I (or just about anyone), can produce a 6” fan by running a 5 stage turbine at 9.5 psi through an HVLP gun that will produce a flawless cabinet grade finish. Meanwhile, a 6” fan through an airless machine requires about 3000 psi, a whole lot more material and yields a poor result.
A More Efficient Delivery
HVLP systems routinely deliver materials (conservatively) in the upper 80% range, 86-90% transfer efficiency seems to be the standard range of quality turbine systems. Airless guns are so much lower by comparison that manufacturers generally don’t share airless gun transfer efficiencies, focusing instead on the production value of the technology. While airless are solid production machines, it is a bit of a guessing game as to where in the 50-70% efficiency range they might actually measure.
In three decades of spraying airless systems professionally, there have been many times when I have personally observed as much material landing on the floor and on the operator as on the walls or ceilings being sprayed.
By way of quick summary, the obvious advantages of HVLP over airless for fine finishing include:
- Less materials consumed
- Quicker set up and breakdown
- Better quality finish
Misconceptions About HVLP
In my opinion, and this ties back to the desire of all consumers these days to find “the one that can do it all,” HVLP is sometimes overlooked by finishers because it is perceived as a specialist. And, to an extent, in the big picture of painting, it is. You probably won’t paint an entire home interior with an HVLP. Large scale production of many thousands of square feet at a time is not its strength. That’s fine, there are other machines built for exactly that.
However, it is possible to find enough variety of finishing tasks for an HVLP to become a general solution to a whole range of specialized task types that would otherwise be best suited to manual (brush and roller) application. HVLP shines in projects that are too small, complex or detailed for larger technologies, and too large or intricate to attempt manually by brush.
A great example of this is exterior spindle and rail systems on decks and porches. We have done many new spindle/rail systems in our shop and just as many onsite in exterior repaint situations. Another example would be a small quantity of interior or exterior doors. Take a quantity of 5-6 interior doors. Not worth setting up a pump and hose style sprayer, but quick and easy with an HVLP system. Custom cabinetry and millwork applications are another specialty.
The bulk of this discussion has centered around using HVLP as a more qualified replacement for airless sprayers in waterborne primer and paint grade situations for fine finish applications. One last strength I would mention is the absolute mastery that HVLP demonstrates in waterborne clear finishes. This is a realm where airless spraying is mostly incompetent, because airless pumps just aren’t happy operating at low pressures in thin viscosity materials.
So, it is possible to “have it all”, at least within the discipline of small scale fine finishing, and HVLP is the solution.
The two key considerations in choosing a wood-floor finish are resistance to scratches and the large surface to be covered.
To stand up to abuse, you need a very durable finish, and to avoid filling the room with overspray that will settle and stick to the finish, you need one that dries slowly enough so it can be applied by hand. The two best choices are oil-based polyurethane and water-based polyurethane.
Oil-based polyurethane is more durable than water-based, but it has a strong odor that hangs around for several days, and it has a slight orange coloring (usually referred to as “yellowing”). Water-based polyurethane has very little odor, almost no coloring, and it’s much easier to clean up. Water-based polyurethane also dries relatively rapidly. So you have to work much faster, being sure to keep a “wet edge” so overlaps don’t show.
Oil-based polyurethane is the best choice if the color and odor aren’t problems. Water-based polyurethane is the best choice if you want to preserve the color of a pickled or very light wood, or if odor is a problem. You may be able to buy a more durable, two-part, water-based polyurethane from a flooring-supply store. Be sure to check on the toxicity of the product and the safety precautions you should take.
Use a large brush, sponge mop or lamb’s wool pad to apply oil-based polyurethane. Use a large brush or paint pad to apply water-based polyurethane. A paint tray provides a convenient reservoir to hold the material.
Water and oil don’t mix, but water-based and oil-based finishing products can be combined as long as the previous coat is dry. Water dries considerably faster than oil so you can apply an oil-based finishing product over a water-based product within a couple of hours. On the other hand, you should allow at least overnight, and often several days, before applying a water-based product over an oil-based product or you may get wrinkling or poor bonding.
Posted on June 12th, 2013 No comments
Every year Apollo Sprayers, International, Inc., offers a gift certificate to the three winners in the Excellence in Finishing Division of the Design in Wood Exposition at the San Diego County Fair. I am honored to be asked to judge the extraordinary entries submitted. Submissions are made by professionals, custom woodworkers and amateurs. Projects can be sold at the Fair or “not for sale.”
This year judging was as difficult as can be. Although I am judging finishing, other aspects of the piece naturally come into play. I do have some guidelines as follows:
And the finish:
- Do I like the look of the piece?
- Is the piece well constructed?
- Are the details, such as joints well done or do they detract from the quality?
- If there are drawers, do they work well?
- Is the sanding well done, or are there marks?
- Is the piece sanded to an appropriate level?
- Is the coating appropriate to the piece?
- Are there unseen places left unfinished?
- This year’s first place winner is Pam Goldman. She made this beautiful media center.
Pam’s inspiration was the Danish Modern furniture made by James Krenov. Pam works at Woodworker West Magazine and has attended the Fair for 15 years. She has been constantly exposed to the work of wonderful creative woodworkers through the magazine and the Fair. Ten years ago Pam decided that she was going to create a piece to enter and she started taking classes to use tools correctly. Just as it has happened with so many of us, her woodworking obsession took hold. Now Pam would rather be in her shop than anywhere else in the world. Pam’s media center took 9 months to create. It is finished with oil, but now she will start experiencing spray finishing with her prize: a new Apollo ECO-3 with the E5011 gun.
Pam feels humbled and thrilled to be the winner. Her beautiful media center will take center stage in her home.
Second prize went to Hugh Elliot for his magical Wizard’s Wedding Chest.
The Third Prize went to Bob Manrual for his unique and inventive lamp, The King.
Posted on June 12th, 2013 No comments
The accompanying picture shows a very bad case of “washboarding,” the compressions left by jointers and planers, especially when they are not adjusted well, as is the case here.
Washboarding is highlighted by a stain; it isn’t disguised or hidden. So it has to be totally sanded out before staining if you don’t want it to show.
To remove washboarding efficiently, begin sanding with a coarse-enough grit sandpaper to sand through the problem efficiently, without creating larger than necessary scratches that then need to be sanded out. In this particularly bad case, you might actually begin with 60 grit, which is very coarse.
Remove the problem entirely before switching to a finer grit. Sand up through the grits until you reach 150 or 180 grit. For the finest grit you’re using, sand by hand with the grain to remove squigglies left by random-orbit sanders.