It’s time for everyone’s favorite topic: finishing!
I plan on using polyurethane to finish my Sitting Bench Step Stool, and this time, I’m not going to use an expensive specialty varnish. Instead, I’m making my own wiping varnish by diluting some good old Minwax Polyurethane 50/50 with mineral spirits. But before I apply the poly, I need to apply a single coat of Zinsser Bullseye SealCoat Dewaxed Shellac as a sealer. This is a good precautionary measure for just about any wood as the shellac seals off any impurities or oils on the surface. But if you happen to be using a naturally oily wood (many exotics fall into this category), this is a necessary step when using an oil-based varnish topcoat. If you don’t do this, the oil-based finish will have difficulty curing.
A Finishing Strategy
No matter what finish you use, the first coat is usually very forgiving. The wood is so thirsty that you aren’t likely to see any drips, runs, or streaks. So that’s why the first coat is the perfect time to establish your finishing strategy. Years ago, I created a DVD called A Simple Varnish Finish. The board I used for demonstration was nice and flat and as a result, the first question most people ask after viewing the DVD is “What about curved surfaces and assembled pieces of furniture?”. So to help fill in that gap, I decided to use the Sitting Bench Step Stool to demonstrate my personal strategy. Which part get’s finish first, second, and so on?
There are really only two rules that I like to keep in mind during this process. First, is to finish the least visible parts first. As you apply finish to any piece of furniture, there will always be a chance for drips, runs, and even finger prints to find their way into the finish. So if I leave my “show surfaces” for last, I can be absolutely sure that the most visible surfaces look perfect. If a secondary surface has a slight flaw, it isn’t nearly as big of a deal. So in the case of this project, the underside is where I start.
The second rule I follow is to follow the finish. As you apply finish to any particular piece, let’s say the stool’s leg, you are bound to get finish on the connecting parts. So pick the part that seems to have the most finish on it already and start applying your finish there next. Since every piece of a project tends to connect to another piece of the project, you can simply move from piece to piece by “following the finish”. If you work quickly enough, you should be able to blend all of the parts seamlessly.
As with any project, you’ll want to sand between coats with a high grit paper and remove the dust with a vacuum or a damp cloth.
Finishing the Finish
Let’s face it folks: our shops are terrible places for wood finishing! As much as we might try to keep things clean, there will always be dust in the air and our finishes will inevitably have grit and nibs in them. So we need a way to smooth the final finish so that the end result is a silky surface that just begs to be touched. The secret is an old technique called rubbing out. The idea is to use fine abrasive compounds to get rid of any imperfections. But instead of using abrasive compounds and a ton of elbow grease, I have a quick and dirty method that still produces fantastic results. The secret is to use high grit abrasive foam pads with a lubricant to abrade the surface. You can use various lubricants including soapy water and mineral spirits, but I prefer to use a simple solution of 50% mineral oil and 50% mineral spirits (thanks to a tip from William Ng). Since the mineral oil doesn’t cure, you have plenty of time to massage the surface and get a nice even appearance. The grit I uses most often for this operation is 2000.
The end result is a finish that will simply blow your mind. Silky smooth and not something you would expect from the average dusty garage or basement shop.
I hope you enjoyed this project. Although it is small in stature, there are lots of little details that go into making it special. I hope you build a few for yourself!
Original Article: http://www.thewoodwhisperer.com/videos/sitting-bench-step-stool-pt-3/
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