GSP core of Monic lines

[Mangrove Cuckoo]

James,

Help me out here? I follow the logic and your equations for floating lines and I cannot find a fault... but something doesn't jive with my experience.

Doesn't the material property play a part?

I have tried PVC lines (the most common), but also PU (from that company that must not be mentioned), and latest, PE lines. Each (of supposed same weight, ie labeled #) took up more space on the reel. So, to maintain the same length of backing on the reel each line had to sacrifice some length off the back end.

I chalked it up to differing densities of the materials determining the line diameter.

And, just out of curiosity, what would you guess the density of an intermediate line would be?

[Lasse Karlsson]

Mangrove, what where the actual lineclass of those lines?
The lines from the manu that must not be named, are all at least one size up. The manu of PE lines, is gping the same route as the manu that must not be named, and quite a few of the newer pvc lines are also at least one or two classes up. Going up in weight means going up in thickness. Also, there seem to be trend towards 100 feet lines rather than 90 these days...

Cheers
Lasse

[James9118]

Hi MC,

As Lasse implies there are a number of things that will effect the volume of your line on the reel. Head length and overall length of the line has a big influence obviously. Then there's the issue of what the line rating truly is - not what's written on the box :-)

All the main materials used in fly line construction have a density of >1g/cc (although I'm finding it hard to find data on polyurethane as there's so many of them). As such the manufacturers add GMB (glass micro balloons) to bring the density into the buoyant region. Obviously the calculation of how much GMB to use has to account for the density and volume of the core. However, ultimately the fly line 'composite' ends up with a density in the region of 0.8 - 0.9 g/cc, and thus for an identical AFFTA rating the volume doesn't have much scope to change (over the measured 30ft of fly line).

I wrote a FP a while back about how to measure the density of a fly line at home - all you need is a fairly accurate kitchen balance (I can try and find the FP if you would like to read it). I used the method described to measure a MED line and a super fast sinking 'T' line, the latter had a density of 2.2g/cc if I remember correctly. As such, I'd say 2.2g/cc is about as dense as sinking lines get, I would estimate an intermediate line would be around 1.1 - 1.3 g/cc.

Cheers, James.

[Lasse Karlsson]

https://www.sexyloops.com/index.php/ps/i-am-being-dense

James' frontpage about measuring density

Cheers
Lasse

[Viking Lars]

Yes, Paul is wrong. Unless the line was denser than normal, or lighter than the AFFTA rating, then it can't possibly be thinner (unless he was just referring to the running line).

James, I agree that Paul could be wrong :-). I also agree that there are physical limitations to how thin a line can get, at least when it needs to float. But if a say .8cc line is built on a standard, dacron core that is thicker than a same-breaking-strain GSP-core, then the GSP-core-line should be thinner in my quite non-mathematical brain. Or not?

[James9118]

But if a say .8cc line is built on a standard, dacron core that is thicker than a same-breaking-strain GSP-core, then the GSP-core-line should be thinner in my quite non-mathematical brain. Or not?

Hi Lars,

No, not necessarily. I think the confusion lies in the composite nature of the density. In your question you've said an 0.8 g/cc line is built on different cores. Now if both lines are 0.8 g/cc and are the same AFFTA rating (same weight) then they have to be the same volume, thus the same diameter.

I believe what you're thinking is that if you apply the exact same coating to each then the dacron-cored line will be thicker and you would be correct. However you wouldn't apply the exact same coating to each - you'd adjust the GMB content to hit the target 0.8 g/cc density. In simple terms you've got a three part composite that needs balancing to give to overall density; core, PVC (or PU) and GMB.

If you apply the exact same coating to different cores (i.e. the same PVC/GMB mix and thickness) then you will end up with a different overall line density on account of the different cores.

Perhaps I'll do some worked examples with different cores to demonstrate the above because I agree it's not intuitive.

Cheers, James.

[Paul Arden]

Hi James.

I suspect it depends, but is PU or PVC more dense? I tried to work this out some time ago but I got many densities for PU.

Cheers, Paul

[Mangrove Cuckoo]

I suspect in my case I might have thrown in another variable... I was comparing intermediate lines. I also suspect the fact that I was particularly interested in clear ones may have made it further from the floating criteria as GMBs probably cannot be used?

The "standard" that I was comparing the others to was a PVC line that was not clear, which may have skewed things a bit too. I suspect PVC cannot be clear?

That might be why the clear ones are of other polymers?

[Paul Arden]

Hi Gary,

I'm sure that PVC can be clear, and that both RIO and SA produce them. With the second version of SL Lumiline it is an Intermediate line so no GMB which increases its "glow". There are clear floating lines around too, however I don't think they are less stealthy and they are a pain in the arse to judge distance. I like clear intermediates (the SA line when it first came to market in the UK was called the "slime line"). But I have a real problem judging distance with these lines - not a problem when Stillwater fishing and throwing distance, but it is a problem for me when trying to place the fly one inch from the bank! Cortland used to make a wicked Intermediate line in blue; long belly, fantastic to fish. Clear "glass lines" from barstool did change things in the UK, but not in my opinion because they were clear, but instead because they had a slightly faster sink rate. Why this was the case I don't know; possibly because of the material. Incidentally I've never found polyurethane a slick material for shooting, but there is no question it is tough. A friend of mine in NZ had a clear intermediate barstool line that took on some sort of luminescence, which he didn't like. So he tied it to his car number and drove it for 10km around some gravel roads! Apparently it was much better after that!

Cheers, Paul

[Lasse Karlsson]

Hi guys,

I'm very curious about the GSP core of Monic fly lines. As it claims to be a thinner core thus contributes to a smaller diameter fly lines overall. I haven't got hands on one though, anyone knows the diameter difference and the line stiffness?

Cheers
TC

Finally found the runningline, and seems like no one beat me to a measurement

I do not know if the full lines sport similar diameter, this one is 50 lbs core, and thin. But as the core is superbraid, ie non stretch the only nice thing is bite detection, all else sucks


Cheers
Lasse