Application of Sikaflex 290DC – Instructions for Caulking Teak Decks

Sikaflex Sealant
The Sanding Process
Following 7 days curing the deck is ready for sanding. Prior to that, however, excess cured Sikaflex 29 DC should be removed with a sharp chisel or knife. This procedure will avoid excess pullon the edges of the seams during the subsequent sanding operation. For effective sanding results use an industrial sander. It is recommended to begin with a medium (80) progressing to a 120 grit or finer. Suitable sanders are beltsanders, flat plate sanders or elastically suspended sanders. Sanding should be along the direction of the seams.
The Finishing Touch
Although we do not recommend the application of a finish to the exterior teak deck, many boat owners prefer to apply a lacquer finish to the deck after sanding. Generally great care should be taken as finishes contain solvents or plasticisers which can adversely affect the cured Sikaflex 290 DC or the drying of the lacquer.  The following criteria should always be taken into consideration:
  • Never apply the lacquer finish to uncured Sikaflex 290 DC.
  • Waiting time of at least one month before application of the finish is recommended.
  • The compatibility of the lacquer  should be evaluated on a small sample area of the teak deck before application.
  • Rigid lacquers have a negative effect on the elasticity of the joint and may crack or cause loss of adhesion of the Sikaflex 290 DC from the teak planks.
It is important to wet and rinse  the deck regularly with fresh  water in order to prevent drying out. In warm climates this procedure should be carried out on a daily basis. The occasional use of a mild detergent (natural liquid soap) diluted in water should be kept to a minimum. Bleach and aggressive chemical cleaners should not be used.
Prefabricated teak decks often consist of a multilayer construction, e.g. they are made of wood onto which a fine layer of teak is bonded. The base wood might consist of various wood qualities; the pores in the “wood” are different in structure and size, therefore the caulking compound is not always in a position to expel the air pockets from the pores during caulking. As a result small bubbles within the joint may surface during caulking. To avoid the development of these “air” bubbles, we recommend tooling the joints using a smooth, slightly flexible spatula at an angle of 45°, expelling air from the pores and allowing a perfect joint to develop during cure.