We do a lot of repair of the finish on cabinet doors in our shop for our clients. Very often people complain that the finish seems to have disappeared in places on the false drawer front and doors under the sink while not having done so elsewhere (except above the stove which I will deal with in another blog). There are places on these doors where the finish is worn, dull and/or blistered. What causes this? Most often it is due to water that has spilled on the door or transferred from our wet hands when we open the doors.
This exposes a consistent weakness in the finishing process of many manufacturers. While most companies use very high quality varnishes or lacquers the problem is they do not apply a thick enough coat to protect the wood. In most cases, the manufacturer’s spray on only two coats which results in a minimal buildup of only 3 mils whereas 5-6 mils is recommended and can only be achieved with 3 or more coats of varnish or lacquer. So, there is not enough finish on the door especially on the end grain and at the joints between the frame and panel of the wood.
In the case of the end grain, which is the grain at the top of the door (see picture below), the open pores of the wood are not filled with enough finish to keep water from getting inside the wood. Once the water enters the unfinished wood below the surface evaporation causes it to condense under the finish (much like water collects on a skylight or greenhouse roof) and then blisters the finish exposing the now-raw surface wood to more damage.
Likewise, water tends to collect where the center panel meets the frame at the bottom of the door (see picture below) and is drawn by capillary action into the groove of the frame where it then is absorbed by the raw wood panel and causes the same damage as the end grain situation.
1) Pay particular care to avoid getting these parts wet and if they do get wet dry them off immediately.
2) If your cabinets are new and you don’t see any damage yet you can either use paste wax or spray lacquer or varnish to add the coats that the factory failed to put on there.
a. Wax is the simplest but needs to be re-done every 6 months or more depending on how hard you are on your cabinets. Be sure to use paste wax (Johnson’s floor wax, Minwax, Trewax, etc), not liquid wax, lemon oils or sprays like Pledge. Paste wax is the most durable of the easy to apply protectors.
b. Spray varnishes or lacquer are more durable and long lasting but require more work. If you choose to do this you must do it outside in an open area for safety and follow the finish manufacturer’s directions. Before spraying the whole door test a small area on the back of the door to be sure the finish will adhere to the old f finish. Apply 2 or 3 coats with special attention to the end grain and the joints where the panel meets the frame. Sand between coats with 320 or 400 grit wet (black) sandpaper. If you are spraying the false drawer front be sure to coat the back which is usually left unfinished by many manufacturers.
3) If your cabinets are old and damaged you will need to use a spray finish as in 2b to restore the finish (paste wax will not do the job in this case). In this case, first wash the door using an extra fine 3M pad and mineral spirits (paint thinner) to remove any traces of food residue, grease, etc. Allow the door to dry completely and then lightly sand the whole door with the 320 or 400 grit paper. If the door is discolored you can attempt to apply some stain to the raw spots but you are better off doing this after you spray one coat of finish on the door. (Usually the stain will not penetrate into the wood fibers due to presence of some finish in the pores). Use a fast drying stain such as Rustoleum Ultimate Wood Stain (which takes about an hour). If you use a stain like the typical Minwax oil base stains you will need to allow it to dry for about 24 hours before spraying on any additional coats of finish. Brush the stain on with a small brush and blend it into the surrounding area. About a week after applying a spray finish (to allow for curing) you can then use the paste wax as noted in 2A above.
4) Or, you can have us do this for you at our shop.
As always, if I can help you with this or other cabinet problems do not hesitate to email me.