The good news is that testing a misfire code, or misfire codes, or a rough idle condition is not that hard and it's something you can do! In this tutorial, I'm going to explain in some detail the most common causes of misfires and misfire codes (P0300, P0301, P0302, P0303, P0304 -OBD II equipped 1.8L Toyota).
Solder flux is a type of metallurgy component used when soldering two metals together. The flux is an inert substance that prevents the formation of metal oxides at extreme temperatures.
Flux paste is a cleaner and corrosivepaste to work with copper and other metals to help the solder attach to the other two pieces that your soldering.Source(s): 20+ yrs in bldg maint field.older flux deos a couple things, it helps keep the guns element clean and it helps the solder bond to the part in question. You can buy rosin core solder with the flux already inside the solder, this is much easier to use then to use solder flux.