Fly Line Weight?

[Dry Fly Rie]

This might be a dumb question, but here it is anyways...

Is there a way to determine the weight of a fly line if it's not labeled?

Context: I just got a Lamson Konic 3.5 on eBay, and unbeknownst to me, it came with backing and fly line, but there was no info on the line. I've tried contacting the seller, but they don't seem to know. It appears to be a floating line, and based on the reel, I'm assuming it's a 7 or 8 wt line, but I'd like to try and figure it out.

Thanks.

[RichardCullip]

I've got a tiny little spring-loaded scale that's built for measuring the weight of fly lines. It's made by Umpqua. You are welcome to borrow it if you want. http://troutsflyfishing.com/store/umpqua-fly-line-scale

[Papasequoia]

First you will need to measure the line, then find a two or three story building (depending on length) with a window access. Then you should tie a small weight on your line and drop it from the window. You should increase the weight you are dropping by increments (a good barbell set should give you a large variety of weights). When the line breaks, depending on the amount of weight you have used, you can use a simple calculation to find the weight of your line. Use this equation to find your line weight: x=line length plus y=amount of weight attached to line when breaking point was reached, divided by terminal velocity times pi. Who says you don't need algebra in real life?

[Ants]

I have ended up with unknown fly lines, also.

Fly lines are rated by the weight of the initial 30-ft. (I am sure I will be corrected on any faulty memory.). Strip of 30 feet of line, and coil it so it fits on a small digital scale. The person who helped me (thanks Joe M.) had a scale calibrated in grains, so it was converted to ounces. The line weights are a range of values.

So, the deciding factor is the scale and the table of rated weights.

Since many of my rods are older fiberglass, bamboo, or other that are not clearly rated, some test casting tells me if the rod and line seem like a good match.

Ants

[drabo2000]

As mentioned by Ants and Richard measure the first 30 ft on a scale - the only trick is to hold the line that is not part of the 30 ft coil so that it does not affect the scale as well as you can. Google "AFTMA line weight table" to find the range of grains for each line weight (google convert ounce or gram to grain if you use a scale that does not handle grains). Richard's Umpqua line scale registers line weights not grains. (A line manufacturer or two labels some lines 1/2 to 1 line weight heavier than shown in the AFTMA table)

Actually most rods will cast OK with a relatively wide range of line weights so as suggested by Ants the practical test is to cast that line on a range of rods and see which are acceptable...

Steve

[fly addict]

First you will need to measure the line, then find a two or three story building (depending on length) with a window access. Then you should tie a small weight on your line and drop it from the window. You should increase the weight you are dropping by increments (a good barbell set should give you a large variety of weights). When the line breaks, depending on the amount of weight you have used, you can use a simple calculation to find the weight of your line. Use this equation to find your line weight: x=line length plus y=amount of weight attached to line when breaking point was reached, divided by terminal velocity times pi. Who says you don't need algebra in real life?

Jon,
I think you forgot to adjust for the earth’s rotation and the phase of the moon in your calculation.

Mark

[John Harper]

First you will need to measure the line, then find a two or three story building (depending on length) with a window access. Then you should tie a small weight on your line and drop it from the window. You should increase the weight you are dropping by increments (a good barbell set should give you a large variety of weights). When the line breaks, depending on the amount of weight you have used, you can use a simple calculation to find the weight of your line. Use this equation to find your line weight: x=line length plus y=amount of weight attached to line when breaking point was reached, divided by terminal velocity times pi. Who says you don't need algebra in real life?

Jon,
I think you forgot to adjust for the earth’s rotation and the phase of the moon in your calculation.

Mark

And what about the Coriolis effect?

John

[briansII]

Most fly lines are rated by the first 30', but some specialty lines are not. Add to that, some lines are heavier to load fast rods, or launch big, heavy flies, and the AFTMA standards aren't so standard anymore. Still, if the line doesn't have any color changes, or looks unusually thick at the leader end, it'll probably fall into the AFTMA rating.

Much easier to cast the line, and see how it feels.......or toss it in the trash like I did this week on a ebay reel. Spare spool lines will end up with the same fate.



briansII

[Papasequoia]

Darn it, Mark and John, you guys are right - I totally left those factors out of my equation! Well, now I guess you can see why I took astronomy to get out of the UC calculus requirement - math just isn't my strong suit.

[Dry Fly Rie]

Thanks for all of the info, guys. I might see if our school's science department has a good enough scale to weigh the line there. If not, Richard, I might take you up on your offer and try and borrow your scale, since you're not too far away.

Thanks for all the help.

[RichardCullip]

Thanks for all of the info, guys. I might see if our school's science department has a good enough scale to weigh the line there. If not, Richard, I might take you up on your offer and try and borrow your scale, since you're not too far away.

Thanks for all the help.

Just let me know when you want to come over or we could met some where (SD Bay) and get her weighed.