Newsletter #160
#160
Greetings from Bill Boxer,
Sr. Vice President, Apollo Sprayers International, Inc
In 2016 Apollo Sprayers Celebrates 50 continuous years of innovating, manufacturing and selling HVLP spray systems.We start our celebration with a special coupon promotion. We hope to entice those of you who have been sitting on the fence and thinking about purchasing an Apollo turbine system, with a special valued offer. (See the offer on the right)
This month our POWER Series models will add some new features. Each model will add an analog hour use meter and the POWER-5 will now have a Hi-Lo PSI setting.
Don’t forget that Sunday, May 10th is Mother’s Day. Perhaps you have a lovely object for your wife, partner, mother, sister, aunt, grandmother or anyone else who means a lot to you.
Finishing Feature Article: by Carl Duguay
Fillers – When Smooth isn’t Smooth Enough
So, you’ve just finished that stellar table top and you’d like to give it a ‘smooth as glass’ finish. What’s a woodworker to do? Why, ‘Fill and Finish’ of course.
There are two kinds of ‘fillers’ – putty type fillers used to fill scratches, dents, and holes in wood, and grain (aka pore) fillers that serve to level out the surface of open grained woods. It’s the latter filler that concerns us here.
Woods such as oak, ash, elm, mahogany, chestnut, walnut, wenge, and teak are characterized as having ‘open grain’ because the wood pores are large. In contrast, ‘closed grain’ woods like hard maple, cherry, poplar, beech, and bubinga, have much smaller pores.
You don’t have to fill the pores of any wood before applying a finish – and a lot of woodworkers don’t. It’s a matter of what you want the final surface to look (and feel) like. If you want to achieve a super smooth finish on open grained woods fairly quickly, then your best bet is to fill the pores before you apply your chosen finish. Good candidates for pore filling are large horizontal surfaces – the tops of tables, desks, sideboards, dressers, fancy boxes, and the like.
Carl at Work
Sealing is Not Pore Filling
A sealer coat, washcoat, or a sanding sealer won’t necessarily fill wood pores.
The first coat of finish you apply to a wood surface effectively seals the wood, which is why it’s called a ‘sealer coat’. However this coat doesn’t necessarily fill up all the pores – especially on those open-grained woods I mentioned above.
When you apply that first coat of finish (i.e. the sealer coat), the wood fibres will likely swell, giving the surface a fuzzy texture (known as ‘raised grain’). This is especially apparent with water-based finishes. Before you apply subsequent coats of finish you’ll want to sand off these fibres. Once you’ve sanded back the raised grain, it won’t occur again.
To make it easier to sand back this first coat of finish, many woodworkers will thin the finish with it’s appropriate solvent, or use a 1 pound cut of shellac. This thinned version of the finish is called a ‘washcoat’. In production shops, where they often spray on lacquer or varnish, they’ll typically use a commercial product called a ‘sanding sealer’ rather than a washcoat.
Oil or Water
There are two basic types of grain fillers – solvent (or oil) based, and water-based. You’ll want to use an oil-based filler only with an oil-based finish. However, you can use a water-based grain filler under either an oil-base or water-based finish. I use water-based fillers all the time now. They don’t emit toxic fumes, making them safer to use, better for my health, and better for the environment, and they’re easy to apply and compatible with any finish. The only issue is that, as with all water-based products, they dry fairly quickly. The water-based filler I’ve recently been using is Aqua Coat’s Clear Grain Filler.
If you’ll be finishing with a penetrating finish (tung, linseed, wiping varnish, or oil/varnish blends such as Danish oil), it’s best not to use a pore filler, as these as they don’t cure hard enough.
Colour or Not
If you plan to stain the wood surface, you can do so before or after applying the filler. The fillers themselves come in clear, natural, and some colours. You can add a colorant to the clear or natural fillers. Regardless, the filler will likely take the stain differently from the surrounding wood, and sanding after you stain might result in some of the stain being removed. To avoid disappointment, it’s best to do some test staining on scrap wood cut-offs before you commit to your project.
Easy to Apply
The water-based filler that I currently use, Aqua Coat Clear Filler, is very easy to apply. The only caveat is that you have to work in small sections at a time, and reasonably fast. Though the process is quite simple, I’d suggest you begin by sealing and filling a test piece or two – particularly if you’ve never done this before.
I almost always sand with a random orbital sander, up to 180-grit, followed by hand sanding with 220 grit, in the direction of the grain. After wiping the surface clean with a tack cloth I apply a seal coat. Because I use a fair amount of shellac, and usually have a batch laying about, I seal the surface with a 1 pound cut of blond shellac. I let the shellac dry for a couple of hours and then lightly sand the surface with a piece of used 320- or 400-grit sandpaper. Just kiss the surface to remove any bits of raised grain and dust nubs.
You don’t need to mix Aqua Coat Clear Filler before using it. Just scoop a tablespoon or so and drop it on the work surface. The objective is to pack the filler into the pores of the wood. The easiest way I’ve found to do this is with a rubber squeegee. I suppose you could also use an old credit card. Work the filler diagonally to the grain and don’t forget to do the end grain. Aqua Coat spreads easily, and I find that I can do about one square foot of surface in under a minute. I’ve never felt the need to thin the filler with water.
Using a squeegee makes it easier to control the filler, and usually I end up with a very thin, even coat spread over the work area. You can easily see if all the pores are filled by looking at the surface at an angle, against a bright light beamed obliquely to the surface. Once the surface begins to dull I wipe it down with a cloth, across the grain, just enough to remove any bits of paste that haven’t gone into the pores. I’m not overly concerned about getting every single micrometer of space filled, as I always lay on a second coat of filler after the first coat has dried for at least an hour. Before repeating the process I’ll lightly sand the surface with 320- or 400-grit paper. While I like to let the surface cure for a few days before applying the finish, I don’t think it’s absolutely necessary.
There are no secrets to pore filling. The only thing that will guarantee success is practice, followed by experience. Once you’ve gone through the process a few times you’ll get a feel for how much filler to use, how best to pack it into the pores, and how large a surface area you can comfortable fill at a go. And, I bet you’ll be able to say “Pore filling – piece of cake!”.
Products of the Month:
Aqua Coat Premium Water-Based Clear Grain Filler 15% off
Aqua Coat Premium Water-Based Natural Wood Putty 15% off
both products are: Non-Shrinking,Water Clean-up,Non-Flammable,Non-Combustible, Low Odor,Quick Drying, Easy Sanding Try a quart of SafeCoat coatings. Or if you already love it, buy a gallon!
SafeCoat Polyureseal BP 15% off, A durable, high quality water based finish, quarts or gallons
Safecoat Acrylacq 15% off HIGH SOLIDS yet LOW VISCOSITY (HSLV) quarts or gallons performs like lacquer without the toxicity, produces the highest waterbase luster
Zip Sanders, 20 % off, make sanding easy and efficient, all Zip products
Micro-Mesh, 15% off includes all high grit sanding products
Our super Spring Special is the Apollo E7000 Non-Bleeder Turbine only Quart cup gun, $229.95 & free shipping, full pattern control, excellent atomization, low maintenance & minimal overspray,
Wizard’s Wedding Chest by Hugh Elliot
Videos are the way to go! Click here to see some of our products in action.
Finishing Tips by Bob Flexner:
Sanding
When sanding wood in preparation for a stain or finish, you need to remove all the problems in the wood – mill marks, tear outs, gouges, etc. – with the coarsest grit sandpaper you’re using before moving on to finer grits (to remove the coarse-grit scratches). This means that the coarse-grit sandpaper you begin with should be able to remove the problems quickly and efficiently to reduce the amount of work required.
As an example, 100- or 120-grit sandpaper is usually coarse enough to begin with. Beginning with 150-grit sandpaper is usually inefficient because you have to sand too long to remove the problems.
On the other hand, with factory pre-sanded veneered plywood or mdf, beginning with 150-grit sandpaper is usually adequate.
These are general observations. We all sand differently, so you may want to adjust the beginning grit you sand with depending on the problems you want to remove. But the basic rule still applies: It’s most efficient to remove all the problems with the coarsest grit you’re using before moving to finer grits.
Testing Finishes for Heat Resistance
Resistance to damage from hot objects is an important finish quality for tabletops and counter surfaces in kitchen and dining areas. The type of finish you’re using will be a strong clue to its resistance. For example, oil-based polyurethane and catalyzed lacquer are very resistant to heat damage, while shellac, lacquer and water-based finishes are less so.
There are two tests for heat resistance that are easy to do.
To test for dry heat resistance, place a metal cup or pot containing water heated to just below boiling on a fully cured finish, as shown in the accompanying picture. Remove the cooled container after an hour and look for splits, indentations or discoloration in the finish.
To test for wet heat resistance, do the same as for dry heat resistance, but place a cotton cloth or cheesecloth wetted with the same hot water under the cup or pot. After an hour check the surface for splits in the finish or discoloration.
Testing Finishes for Scratch Resistance
Finishes vary in hardness and scratch resistance. To a large extent the relative hardness of various finishes are known. For example, oil-based polyurethane is more scratch resistant than lacquer or shellac. So are catalyzed finishes and water-based finishes. But what if you want to be more exact about the differences, or want to compare brands within any single type of finish?
The easy way to do this is with architect’s pencils because these vary in hardness themselves.
Begin by buying a set of architect’s drawing pencils ranging in hardness from about 2B (soft) to 5H (hard). Sharpen each pencil using a knife so you leave the sharp cylindrical edge of the lead intact. If you damage this edge, or if it becomes worn, sand it flat, holding the pencil 90 degrees to the sandpaper.
Beginning with one of the softer pencils, hold it as you would for writing and push it forward across the fully cured finish as shown in the accompanying picture. Maintaining equal pressure, follow with pencils of increasing hardness until you find one that cuts into the finish.
The hardness rating for that finish is the number of the previous pencil – the hardest lead that doesn’t cut.
The Apollo Team will be at the AWFS 15 Show in Las Vegas where there will be a spectacular display and demos of woodworking tools and equipment.