On most manual coating sprayers, the parts are removable and replaceable. However, you should ensure you purchase parts that are designed for your particular make and model of manual coatings sprayer, as there may be some differences in size and design.
Even for a very handy-person, it would be difficult to make the parts yourself, due to their complexity.
As a result, it is more cost-effective and less time-consuming to source the spares you need online via distributors or the manufacturers.
It must be noted, however, that manual coating sprayers are becoming less popular year by year and so spare parts may be hard to find. For this reason, it is advisable to purchase spare parts when you initially buy the manual coating sprayer.