DEKS OLJE D1 works by saturating the wood and nourishing it with oil. It fills the wood's pores with oil and expels moisture and air, thus stabilising the wood and protecting it from inside, while giving a silky oiled finish.
It very much depends on the type of caulking that has been used on your boat deck. Below is a list of caulking types that D1 will and will not affect.
D1 will not affect 2 part-caulking systems, these in general are polysulphide based
D1 will not affect Silicone or Acrylic based caulking
D1 will affect some single pack Polyurethane caulks, such as Sikaflex A1, FC and D1.
The more modern Polyurethane caulks tend not be affected by D1. An example of this would be Sikaflex 290DC. It is important with these types of caulks that they are left to fully cure before D1 is applied. A minimum of 10 weeks is the recommended period of time.
D1 will soften all bitumen based caulks
As with any product we strongly recommend that a small test area be carried out to ensure compatibility before applying D1 to the complete deck.
It is not possible to give an exact answer to this question as all oils are different. However natural oils are unlikely to affect caulking, but we would always recommend trying a small area first.
If D1 has softened the caulking there is likely to be 2 reasons for this.
1 - The caulking is bitumen based and therefore not compatible with D1
2 - The caulking is new and has not been allowed to fully cure prior to applying the D1. The reason D1 softens caulking is that the oil and vapours from D1 leech in to the caulk as it dries.