The free to play armor in TDS is called Castaway, both the armor and the unmade pieces are called this. Also much like all previous expansions you will be able to purchase the unmade pieces of armor in The Bazaar. Castaway armor is arguably the best stuff you can get at level 100 for visibles. Many will say it trumps TBM armor but it can be argued some of the TBM armor is better for certain slots. Castaway does far exceed Latent Etheric armor as does the TBM armor.
Much like Boreal and Latent Ether what you need to do in order to make this armor is head to Katta Castrum and speak with Seersmith Caius and buy the Synthesis Chamber. You will then be able to combine the unmade pieces of armor in this device. Keep in mind that much like with the previous expansions combining the items in this container will not require any solvent.