How do you figure out what line weight mystery fly lines are?

[Josh]

I've got a small pile of various fly lines that are either coiled up in ziplock bags or on random spools I don't use often. Of course none of them are labeled.

Is there any clever way to figure out what line weight they might be? Even general accuracy would be close enough, as these are obviously lines that I don't use often enough to care deeply about. But it's difficult to even give them away if you don't have a clue what rod they might go on.

 

[Zak]

I've got a small pile of various fly lines that are either coiled up in ziplock bags or on random spools I don't use often. Of course none of them are labeled.

Is there any clever way to figure out what line weight they might be? Even general accuracy would be close enough, as these are obviously lines that I don't use often enough to care deeply about. But it's difficult to even give them away if you don't have a clue what rod they might go on.

I wish I knew! A few years ago, started marking the ends of my lines with a black sharpie. The number of bands equals the weight of the line, with a thicker band in the middle or the terminal end to indicate DT or WF.

But I've got some unlabeled lines from before I started doing that that remain mysteries.

 

[Russell]

weigh the first 30' , kitchen scale in grams works, and then convert to grains. This will give you the true wt rating of the line. This may not match what the original box would rate it at since most lines now are .5 to 1+ line wts heavy.

 

[Josh]

weigh the first 30' , kitchen scale in grams works, and then convert to grains. This will give you the true wt rating of the line. This may not match what the original box would rate it at since most lines now are .5 to 1+ line wts heavy.

Just measure out the first 30ft, coil up to a size that will fit your scale, and let the rest dangle off the side?

 

[Russell]

Just measure out the first 30ft, coil up to a size that will fit your scale, and let the rest dangle off the side?

I hold it above the scale in my hand. There is also some level tip on the front that is not supposed to be part of the overal weight but I just weigh about 30' and call it good.

 

[Chucker]

weigh the first 30' , kitchen scale in grams works, and then convert to grains. This will give you the true wt rating of the line. This may not match what the original box would rate it at since most lines now are .5 to 1+ line wts heavy.

This is the way.

The flip side - how do you work out the correct line rating for a mystery rod?

 

[albula]

If you have a 3 wt rod, a 5 wt, and a 7-8 and a little time you should be able to get pretty close if you don't have a scale. You don't have to put them on a reel to cast them.

 

[PhilR]

Just measure out the first 30ft, coil up to a size that will fit your scale, and let the rest dangle off the side?

I shove it in a toilet paper tube to contain it on the scale

If you have a 3 wt rod, a 5 wt, and a 7-8 and a little time you should be able to get pretty close if you don't have a scale. You don't have to put them on a reel to cast them.

I have some rods that don’t like the lines that they’re supposed to, so I’ve tested matchups. The trick is to write it down somewhere so you don’t have to do it at the start of each season.

 

[Skeena88]

weigh the first 30' , kitchen scale in grams works, and then convert to grains. This will give you the true wt rating of the line. This may not match what the original box would rate it at since most lines now are .5 to 1+ line wts heavy.

 

[Skeena88]

@Russell Thank you! You helped me solve a few mysteries with old, but good, lines in my stash!!

 

[Dragon Mo]

I use the 30' rule then cast the line to see how it compares to a known line. (doesn't have to be on a reel) I've had a couple of lines that have apparently never heard of the 30' rule...

 

[Josh]

You don't have to put them on a reel to cast them.

Ahhh, that's clever. Of course you don't. Not sure why I didn't think of that.

 

[albula]

Ahhh, that's clever. Of course you don't. Not sure why I didn't think of that.

If the rod feels out of balance without a reel just put a reel that is appropriate on it with the line reeled in and string the unknown line through the guides. Done it many times.

 

[skyriver]

I have 3 or 4 mystery lines in great shape that I keep meaning to test.
Lots of good info here. Thanks!

 

[Salmo_g]

If you have a 3 wt rod, a 5 wt, and a 7-8 and a little time you should be able to get pretty close if you don't have a scale. You don't have to put them on a reel to cast them.

You may not have to put them on a reel, but if I don't I end up with a rat's nest of tangled line. By the time I get it back in a tidy coil, I forget that my intent was to test cast it and figure out what weight line it is or which rods it fits best.