Designing Defects Out

Probably the easiest way of handling defects is to incorporate them into a part of thedesign so that they are hidden. This is what I did with the knots on the back of thesettle. Many knots that seem large on one side disappear almost entirely on the other sideof a 3/4" board, so putting defects on a back or non-show side works nicely. However,be sure to take into account that furniture gets moved around frequently, so what may be aside facing a wall one year may be a show side later on. The large knots on the oak legsin the photo of another commissioned piece were dealt with in a similar manner, I designedthem so that they faced to the inside of the side table. Once the piece is completed withthe drawer, they will never be noticed. Because this weak area is near the location of amortise, I filled the large knot hole with a polyester filler (like Bondo) to give itstrength, then touched it up with pigments and shellac. (This will be discussed later.)

Another way to handle large defective areas is to place them in the initial layout sothat they fall on an area that will be cut out. This is what I did with a large worm-holedarea on the right side of the settle. Most of the holes fell in the area that I cut outfor the arm. A few holes were left, but they were filled and touched up later.

For the back panel below the seat, I saved all the sapwood cut offs and small widthpieces and glued them up to make a large 8" wide piece. This panel is never seen whenthe seat is down so I wasn't really worried about the appearance of this piece. However,because it is a structural part that supports the weight of the person sitting in thesettle, I avoided wood with splits, checks, and large knots. (This is an important pointto remember, any part that is a load-bearing piece should be as defect free as possible.Sapwood does not affect structural integrity.)

Dealing With Sapwood

I don't always regard sapwood as objectionable, rather, I really like the sharpcontrast between light and dark, especially on dark woods like walnut and rosewood. Butyou have to be careful that it doesn't interrupt the natural flow and form of the piece,like the sapwood on the front panel of the settle. I didn't notice this when I wasbuilding the piece, because in freshly cut cherry, the distinction between sapwood andheartwood is not that obvious. After a month however, the contrast became very obviouswhen the heartwood darkened. It's wise to wait anyway before correcting this problem, sothat you can match the sapwood to the color of the heartwood after it's darkened.

I handled this problem by darkening the sapwood using alcohol soluble dyes. Using afine pointed red-sable artist's brush, I mixed several dye colors together until I got thesapwood to blend in with the heartwood. I find that working with several layers ofslightly different thinned colors gives a much better final color match than trying to hitthe color all in one shot. Once I padded on several more coats of shellac, the sapwood washardly noticeable.

This technique can also be used on pieces that are unfinished. Here I use water-solubledyes, because they are easier to handle and do not dry so fast. I find spraying the dyewith a small touch-up gun works best. The trick with this technique is to anticipate whatthe wood will look like when it's finished, so I find wetting down the wood with waterfirst will give a close approximation of what the wood will look like finished. Thistechnique also works if you're planning on staining the wood with a pigmented wiping stainlike Minwax. The sapwood will literally disappear after staining.

Knots

I really like knots, and particularly, the area around knots. As mentioned above, areasthat will be subjected to stress should be free of knots but other areas, like the upperright top of the settle are open ground for incorporating knots. The area around a knotusually has very swirly dense grain, so care should be taken when finishing, and the useof hand scrapers is suggested. Knots that have large cracks or are loose need to beconsolidated so that they do not fall out or chip later. I use several techniques for thisdepending on how bad the knot is.

Where large cracks have developed, or where large pieces of the knot are missing, smallpieces of wood should be glued in with epoxy tinted with pigments. This is especially trueof knots in walnut. Mix some dry pigment powders into five minute epoxy and glue in smallpieces of wood cut into small enough pieces to jam in the cracks. (Tip -- rather thanmixing the epoxy in the suggested 1-1 ratio, I mixed the epoxy in a 1.5 resin to 1hardener. This results in a much harder glue that scrapes better when fully cured). Whencompletely cured (24 hours) cut down the wood slivers with a flush cutting saw. Notice myhomemade one in the photo. It's nothing more that an old hacksaw blade with the set bangedout on an anvil. I wrap tape around one end to act as a handle. Then I finish the surfacewith a hand scraper.

With smaller cracks, or just to consolidate a loose knot, cyanoacrylate glue can beused. I use the water-thin viscosity because it actually wicks into the cracks bycapillary action, but I usually put tape on the other side to keep the glue from seepingthrough. If you use the accelerator sold with these glues, the area can be scraped andsanded immediately. Don't sand before the glue is completely cured, because the sawdustwill mix with glue and form a light filler that doesn't look appropriate with the darkknot

With large knots that are missing or are powdery and brittle, I usually scrape out theloose pieces and fill the area with a catalyzed polyester filler, such as those sold inauto-body stores. If you buy these type ask for white hardener since red hardener is toostrong a color when dry. These fillers also dry quickly, and I sand the area flush afterabout an hour. They also have the advantage of not shrinking, which is what will happenwith water-based fillers. When dry, I rub some pigmented wax sticks over the area to fillin the small imperfection and bubbles on the surface of the filler and then blend the areainto the rest of the wood area using shellac and dry dyes and pigments. As mentioned aboveI try to hide these large knots as much as possible in the design.

Cracks and Splits

During its life, trees may be subjected to growing stresses which cause internal cracksand splits in the structure of the wood. This is known as reaction wood. This is differentfrom end checks and cracks at the end of the board which form as the board dries. Theseshould always be cut out. On the other hand, cracks and splits in the center of anotherwise good board can be filled with dark tinted glue which has a nice aesthetic look.Very small cracks can be filled with water-thin super glue like "Hot Stuff" soldby Satellite City. Simply hold the tip of the dispenser against the and the glue will wickinto the crack. Tape the other side of the board if the crack goes all the way through.When the glue dries it will look just like a grain line and blend in perfectly. If youdon't want it to appear dark, start sanding with 100 grit sandpaper before the gluesdries. Doing this kicks up some sawdust and push it into the crack along with the glue anddry to almost the same color as the wood.

For large cracks, I use the same technique as the epoxy technique describe above forknots. Using the dry colored pigments, you can tint the epoxy light or dark to create theeffect that you want. Several applications may be in order, because the epoxy will shrinkslightly as it dries. The gap-filling advantage of epoxy is that it also strengthens theweakness in the board caused by the crack. This is what I did on the left side of thesettle, where long cracks went right into the wedged through tenons. The tenons were atight fit and the glue-filled crack stayed put when I drove the tenon home during glue-up.

Worm-Holes

I can't say that I like worm holes so I usually like to place them on areas that willbe hidden or cut out entirely. The other disadvantage is that they severely weaken thewood, so care should be used when using boards that are badly worm-ridden. Severaltechniques can be used, but I like to fill them with tinted epoxy and then touch them upwith shellac and dry powders to blend them into the rest of the piece. You can also use awater-based filler and then tint them with the dry colors. They dry lighter than the colorwhen wet, so you may need to experiment a bit to get the feel of this technique. Thefiller I made dried too dark, so I had to lighten the dried filler up with shellac mixedwith dry pigments. Another quick and easy technique for worm holes are pigmented waxsticks sold by several suppliers like Behlen or Mohawk. Simply push the wax into the holeand then scrape off the excess with a wooden chisel like in the photo. Then smooth itlevel with the paper back of some lightweight sandpaper. Contrary to what you might think,most finishes can be applied over the wax, as long as the area isn't too large.

The extra time I put into fixing up the left over stock for the settle was worth it. Ifigured that I saved over 100.00. That's a good enough reason for me to try and save itfrom the kindling bin. It may take a little extra work, but my wallet sure felt the betterfor it.

Jeff Jewitt owns and operates Homestead Finishing Products – featuringhard-to-find traditional finishing products. 5 Grades of dry shellac, oils, varnishes,brushes and their own exclusive line of dyes make Homestead Finishing Products a must forevery restorers supply needs. Excellent technical advice. Please contact us by:

Also available are Jeff’s Book Hand Applied Finishes, and two videos, Coloring Wood and Applying Topcoats – winners or the 1997 Stanley Award for best How-To book and video.

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