Rush is a sturdy, natural or synthetic material used to weave chair seats. The rush can be left unsealed, but some people choose to apply a finish. If your finish is worn and is spoiling the look of the seat, it may be worthwhile to refinish it. Other wear on woven rush seats includes torn or damaged rush. You can reweave a rush seat if you take the time to practice the skill. The pattern for weaving rush seats does not vary; once you learn it, you can repair or redo a square or rectangular seat with ease.
Determine the type of rush your seat is made of. With synthetic rush material (craft paper twisted into ropes), the finish is likely shellac. Shellac may acquire an orange tint and show fine cracks with age. If the rush is natural (cattail leaves or Chinese sea grass twisted into hanks or rope), a mixture of linseed oil and paint thinner was probably used as a finish. Take a small piece of the seat material to the store for comparison to help you determine natural from synthetic rush. If you are unable to tell which type of rush was used or which finish was already applied, using the linseed oil and paint thinner formula is the most prudent way to proceed, since that mixture won't harm either type.
Clean the rush seat, if needed, leaving any old finish that remains on your rush seat in place. Attempting to remove the old finish can damage the rush material. If dirt is a problem, use a clean, damp cloth to give the seat as thorough a cleaning as possible. Allow the rush to dry thoroughly before proceeding.
Apply a 4 to 1 ratio mixture of boiled linseed oil and paint thinner solution. Apply the mixture with a paintbrush. After each coat, wipe off the residue with a lint-free cloth and allow the surface to dry. You will need several coats.
If your seat was finished with shellac (look for an orange cast and chipping), use a ready-to-paint shellac, which comes mixed with alcohol. Apply one coat at a time using a paintbrush. Allow it to dry. Then brush on a second coat.
Decide which material was used to construct your rush seat and whether or not the repairs needed are extensive enough to require reweaving the entire seat, then purchase the necessary amount of that material. To determine the length of rush you'll need, measure the area you'll be repairing and double that measurement, since the weaving goes over and under the seat. Synthetic rush may be soaked for ease in handling, but should not need the 1 to 2 hours of soaking required by natural rush materials.
Repair any small areas by tying new rush material onto the original. You may need to undo some of the weaving in order to have enough material to tie on to. Always use square knots to join together the rope or hanks. Hide any knots within the weaving or on the underside of the seat. Weave the material as the pattern dictates until the repair is complete.
Reweave the entire seat using the four corner weave pattern: Number each corner, beginning at the lower left and moving counter clockwise, 1 to 4, and label each rail A to D with A at the bottom, B on the left side, C on the right side and D on the top.
Take a strand of rush and lay it over rail A at corner 1, leaving about 4 inches at the end. Draw the strand over the top, then under rail A. Take the strand up at corner 1, over itself and rail B, then under rail B and straight across to the top of rail C at corner 2. Draw this around and under rail C, up at corner 2, over itself and over and under rail A. Pull directly across the frame to the top of rail D at corner 3. Continue this pattern for corners 3 and 4. Repeat the weaving in this way until the seat is complete.
Always use paint thinners and shellac in a well-ventilated area. Old rush material can be used as stuffing between the upper and lower strands when reweaving a seat, so don't merely discard it.
Never leave oily rags in a pile or they might spontaneously ignite.