Home Archives for Finishing
April 14, 2010 By

Sanding between coats of shellac

Some will possibly disagree; however, the results speak for themselves. I prefer to use 600 grit paper to sand between coats of  dewaxed shellac used to seal white oak:

Enjoying the journey.

As I have mentioned before, one key item in a finishing schedule is having the right sandpaper, like 3M’s 216U Fre-Cut™ Gold. I discussed the use of this paper in an earlier article; but I still must remember how critical it is to have the proper tools to do the job. And in finishing, this paper is an essential tool. The surface of the white oak is silk smooth after sanding. The smooth surface will telegraph into the sprayed varnish, yielding a very nice, smooth finish. Who said waterborne coatings were difficult to use?

Note: Sealing the surface of white oak and (especially) red oak is essential when using waterborne coatings. Avoid applying (typically) high-pH waterborne coatings directly on the raw wood surface of high-tannin woods like red and white oak, as pin-holing and bridging are likely to develop; that would make it difficult to get a nice, smooth finish.

Next: Attaching the top, and start spraying the varnish.

— Al Navas

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February 23, 2010 By

Preparing to finish the legs for the stand-up desk

It has been very cold in NW Missouri, which prevents me from using the finishing room to complete the spraying of the toner coating on the dust cover for the desk; I would have to open windows to bring make-up air into the shop (the exhaust fan pushes out 2,200 CFM – a complete change of volume in the shop every 5-1/2 minutes!). So, for now, the dust cover sits in the finishing room, where it is a cozy 74°F. Meanwhile, after many hours shoveling snow, and pushing it around with the tractor, I finally got into the shop again today. And I turned my attention to some pre-finishing on the walnut legs.

Garnet shellac enhances the color or walnut. That is what I will apply as the first step in the finishing process, using lint-free rags. But first, the sanding dust must be removed, using moist lint-free rags:

As soon as the wet rag hits the wood, the grain “raises” and the wood surface becomes rough. I use 600-grit sandpaper with light pressure to remove the raised grain, and make the surfaces smooth again:

The garnet shellac I have been using for several years is Target’s Ultraseal-WB, a waterborne, dewaxed shellac that seems to meld with the Target topcoats; notice the gorgeous color imparted to the walnut by the garnet shellac:

Because the Ultraseal-WB contains water, the wood grain will again raise, but only slightly. With two applications, the coating can be sanded smooth, without cutting through the coating into the wood. I will check results in the morning, and continue with the finish. At this stage, only the garnet shellac will be required, and the legs will be ready for initial assembly of the desk.

— Al Navas

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February 19, 2010 By

Applying a toning spray to the dust cover for the stand-up desk

The surfaces of the dust cover were very smooth, and ready for toning; this meant that sanding was thorough. As I mentioned in an earlier article, I want to apply a dark color to the outer surfaces of the cover; a dark color will minimize the amount of light that reflects from the floor, making it easy on the eyes during long work sessions. The inside surfaces will get a good wax coating, using Renaissance wax.

To prepare the toning finish, I simply mixed a water solution of a Lockwood dye into the Target Coatings’ Emtech 2000wvx waterborne alkyd varnish, waited one hour, and sprayed it on. Another coat or two tomorrow after light sanding by hand, and the dust cover will be ready for final assembly. The final color should be a dark reddish brown, just perfect for the underside of the desk.

Warning: Don’t let the clean looks of the finishing room fool you. I spent a day and a half over the past weekend cleaning very fine dust from all surfaces. The HVAC repair man was here a while back to repair the furnace, and we managed to shake loose a bunch of dust; of course, the dust found its way into the finishing room, via the ducts. I had to install some filter material at the registers, to minimize or eliminate the bulk of this super fine dust. And the furnace got a new 4-inch thick filter.

A housekeeping tip: Don’t delay clean-up of a critical area, like a dedicated finishing room or a semi-dedicated finishing area or booth. I waited too long; but the day and a half I spent cleaning the room paid off, as dust nibs were virtually nil during today’s spraying sessions. The finish on the dust cover surfaces are nice and smooth. Only a bit of sanding will be required before I apply two new layers of topcoat tomorrow.

— Al Navas

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