I have seen this somewhere, but can not find the directions on how to do it. I have some fly rod blanks with out a weight can anyone help?

I have found the best way is to test cast with various lines.

Common Cents info top left will help.

Any rod will cast any line. Fly rod number ratings by the commercial makers is purely subjective. One company's 4-weight rod is another company's 6-weight rod.

The Common Cents System will allow you to peg the rod power and relate it by means of an equation (ERN=ELN) to a line weight that will perform nicely with 30 feet of line aerialized beyond the tip.

...........

Line weights are based on 30', but not everyone normally casts at that distance. Some normally use a particular rod for dry flys others normally use heavy streamers. If the rod is for you, then it would be best to try various line weights at the distance and setup that you normally cast.

If, on the other hand, you are just trying to find the nominal rod weight that the "average" person might find acceptable, then try the Common Cents System.

The CCS will do all the rest, too. It is a simply matter to use ERN=ELN+1 or ERN=ELN-1, or whatever you wish, to find line weights for other distance ranges.



.............