Once a weapon you are not interested in keeping reaches rank 30, instead of selling it, you might want to check if the weapon is required as a crafting ingredient of another weapon: Use + or + to use your browser's search function.
Crafting another weapon does not mean the product weapon is necessarily better than any of its ingredients.
A product cannot be crafted using ingredients that are still waiting to be claimed in the foundry. As such, managing the order in which weapons are claimed is a requirement if you have limited empty weapon slots. For instance, in the process of crafting the AkJagara: if the Dual Skana is claimed before you start crafting the Akbolto, you will need a total of three slots at the same time to hold the ingredients; whereas if you craft the Akbolto first, you will only need a total of two slots at the same time.
Also, if an ingredient is required multiple times such as dual wielding weapons, only one can be crafted in the foundry at a time. For instance, without rushing with platinum, obtaining the ingredients for the Afuris will take a minimum of 24 hours (12 hours for each Furis).
In this section are blueprints that require weapons as crafting ingredients (without mentioning its components). The weapons on the left side are consumed in the process of crafting the weapon on the right.
If you are wondering whether you should delete a weapon from your inventory (based on the currently known weapons available for crafting), use+ or + to use your browser's search function to check if the weapon you wish to discard is present in the left side of this table.
Once the product weapon is crafted and has been fully ranked, you should check if that product may be an ingredient itself. Various weapons including the Dual Kamas, Tipedo, Bolto and Akbolto fall into this category.
*Lex and Lato are purchased in the market for credits.