I just cook baking soda in my oven at 350F for 2good hours and mix it in between and it converts it to sodium carbonate,...i then just add it to some distilled water pinch by pinch and stir it up to let it dissolve in seconds to 1min
And yes,...sodium carbonate makes water feel slimy because its a base,...whenever you freebase a liquid,...it goes slimy...If you ever got NaOH water on your hand accidentally and had to wash it off quickly,...you noticed that it is VERY SLIMY because its a very powerful base.