There is a huge misunderstanding when it comes to sealing and refinishing outdoor Teak furniture correctly. Ask ten different people and you will get ten different answers.
Some people believe that teak furniture will turn an attractive sliver gray if left outside, but the truth of the matter is that most people live in some type of polluted area. With modern day air pollution and intense UV rays due to the depleted Ozone layer, anything left outside will raptly deteriorate. Teak furniture exposed to these elements, will tend to turn black with discoloration. Scrubbing only leave an unattractive blotch look and most teak furniture owners find themselves unhappy with the black or blotchiness and decide that some type of treatment is necessary.
Cleaning: Removing Gray
If teak furniture has turned gray it must be cleaned before applying any type of finish.If your teak furniture has turned gray it can be easy cleaned with a mixture of water and TSP (trisodium phosphate). Apply this mixture with a scotchbrite pad or Synthetic Steel Wool (Never use real steel wool, because little pieces of steel will rust in the grain of the wood).Wet the teak and sprinkle on the mixture of TSP & water.Spread it evenly with a Scotchbrite or synthetic steel wool,give mixture a few minutes to work. While the wood is still wet, lightly scrub in the direction of the wood. Make sure to wet down surrounding areas before you start to protect area from cleaners. After scrubbing rinse wood completely and let dry.
Cleaning: Removing Varnish or Oil
If previous varnish, oil or paint is discolored, peeling or chipping it must be removed before applying a new finish. Varnish, Oil and Paint can be removed by sanding with 60-80 grit sandpaper or the use of a Chemical Stripper.Chemical stripers are designed to brake down the previously varnished or oiled coatings. Apply Stripper with a throwaway brush or spray on the surface of the wood. Allow stripper to sit on surface of wood for 5 to 10 minutes before scraping. Test a small area to see if finish is ready for removal. Then scrape off loosened finish by gently working in the direction of wood grain with a scraping tool or synthetic steel wool. Wipe off sludge with a rough cloth and let dry. If small areas of Varnish or Oil are still remaining, lightly sand wood to remove any remaining old finish.
Teak Oil is excellent for indoor wood but does not have the strength to hold up to the harsh outdoor environment. Most people who use teak oil find them selfs re-oiling every two months. Teak oil is also known to attract fungus and mold. With out the constant chore of oiling every few months, teak oil will fade rapidly. Once teak oil has faded and turned gray it will need to be completely stripped and refinished. There are two types of teak oil commonly used for teak furniture. They are Linseed oil or Tong Oil. Linseed oil is significantly cheaper and will darken teak furniture after it has been applied. Tong oil doesnt immediately darken the wood, but it may be hard to discern that much difference since both oils oxidize in the sun and turn dark after time. If you are going to oil your teak, make selection based on the recommendations of other teak furniture owners in your area.
Apply teak oil with a paintbrush, sponge or lint free cloth. Immediately wipe up any drips or runs with paint thinner. Immediately clean up Teak Oil spills, Teak Oil is known to leave dark stains that are nearly impossible to remove.
Oiling requires lots of coats. Wipe up excess oil on each coat with a cloth. Continue to brush on the oil and wipe away any excess until the wood is saturated. The wood should have a matte finish without any shinny areas.
Another approach to protecting teak furniture and achieving a natural look is to use a Teak Sealer. Durability and ease of application have made some sealers very popular with teak furniture owners.
Water Base Sealers will not replenish (or feed) the natural oils in teak wood. There for it is very important to use a Oil Base Teak Sealer that will replenishes the natural oils and provide protection to block out moisture and dirt.
Teak sealer can be applied with a brush, application sponge or a spray can. Spray application is excellent for spraying between the cracks. Apply a thin coat of sealer in the direction of wood grain and wipe away any excess. Apply additional coats until the surface of the wood shows a uniform finish.
Maintain sealer coat by lightly sanding top surfaces of wood and applying same sealer that you used in the past.
It is a proven fact that stains will out last clear finishes. The reason is that stains act like sunscreen for your wood. Stains protect wood from harmful UV rays that deplete the natural oils found in teak wood.
Although, Teak Stains block sunrays they do not provide adequate protection against moisture and dirt.
There are two ways to apply teak stains. The first way requires that you buy a separate can of stain and then apply additional clear sealer on top of the stain.Let stain completely dry before applying clear sealers.
Or you can use a Teak Stain that contains a built in Sealer. These all-in-one stain & sealers are excellent for quickly staining and sealing teak furniture.
You can think of varnish as a thin layer of plastic on the surface of the wood. Varnish dries to a hard finish and is extremely brittle. If the surface of the wood remained completely still, varnish would be the ultimate coating, but unfortunately teak wood is constantly expanding and contracting due to the changes in our environments temperatures. Because Varnish is very brittle it will crack and peel as the wood moves. Varnish is also known to oxidize if left outside turning the warm amber appearance to a hazy white.
Another important fact is that varnish is extremely hard to maintain. Once Varnish has cracked or peeled, it will need to be stripped with a chemical stripper and sanding.
All though varnish has not changed for many years there are new finishes that let the wood move at the same time providing the hard protection of a varnish. This is accomplished with the mixture of natural oils fortified into the resins. Some companies have even taken it one step further with the use of an Epoxy resin. Epoxy Resin Sealers are some of the toughest resins on earth providing the ultimate strength and durability.
Most Varnishes & Epoxies are thick in viscosity, its important to apply a thin coat in the direction of wood grain and let dry between coats. Varnish & Epoxy are known to have a slight amber appearance and will lightly darken the wood.
How-To Clean & Seal Teak Furniture-Movie