It should be ok until the proper rated one can be found..I would just not run a lot of hardware that would need more than the rated 6 amps..Remember that when the current max is reached it clips and the voltage starts falling off..Thats bad.
What model and make laptop...I may have something...
I agree,it should be ok to use it temporarily.The rating should be for a load close to max (damn engineering approximations).And depending on the charging circuitry,the battery could be called up to provide the extra current if needed.This has happened to me before.Puts undue stress on the battery,and could cause damage there.Then there's the clipping problem: why would it clip the DC output?Unless you were referring to the input circuit?