Dyneema and some number crunching

[Mandelstam]

Did some number crunching in Excel today just out of curiosity on the different manufacturers diameter/break strain numbers. Found some interesting stuff. And it says almost as much about us the consumers as it does about the manufacturers.

I basically wanted to compare the numbers on the spool to what Dyneema is indeed capable of. Dyneema has a yield strength of 2,4-3,5 GPa (Giga Pascal, force divided by area). I know that the manufacturers are "tampering" with numbers and using irrelevant testing methods to try and make their line stronger and thinner than it in reality is. But I wanted to test my theory in a really basic, simple och non scientific way myself.  I selected a few brands and put their numbers in Excel where I calculated the GPa of their line. I took the liberty of deciding that every line was circular in cross section. I know they aren't but if they can cheat so can I. The purpose was not to get exact numbers, just to get a feel for them.

Every brand I tested had higher GPa than the Dyneema fiber itself in some diameters. But the most striking thing was that for every line the GPa was higher in the really really thin diameters while in the thicker diam the GPa went down to a, in theory, possible value. One line (Berkley Whiplash Pro) had a GPa of almost 37 for the thinnest and a 7 for the thickest! (Again, Dyneema's GPa is around 2,5-3,5). But the average line went from a GPa of 5-7 down to 2-3 in the thicker diameters. In my mind the GPa of a line should remain the same regardless of the diam, if it's the same brand and model.

If we, the consumers, stopped shopping lines by only reading the diameter and breaking strength and choose the thinnest and strongest, we could maybe start getting some real data on the spools.

Again, this was a really quick, dirty and very unscientific test but the results was so striking and clear I just couldn't ignore them.

[wallacewt]

hi karl. so how do you choose the thinnest/ strongest
when you go into a shop

[BMITCH]

hi karl. so how do you choose the thinnest/ strongest
when you go into a shop

Yeah x2

[Jeri]

Hi Karl,

This all sounds so familiar from experiences with nylon monofilament, and the extent that various suppliers were going to, to embroider the truth about their products. We get very much the same down here in southern Africa, where mostly folks buy their line by the diameter, as the diameter is a strongly influencing factor in the distance achieved with casts.

A supplier that will remain nameless, took a line testing machine to one of the trade fairs, and offered to test any line, while testing it alongside his own products. Lines that were tested were first mic'ed for thickness, then tested to breaking point on a dry test.

Firstly, only 2 line manufacturers actually came within 2.5% of their stated thickness and then tested truly to the breaking strain. The rest that were tested were either consistently over size or just wishfull in their breaking strain. One particular brand could almost have swapped lbs for kgs!!!! There were also several manufacturers that didn't offer their line to be tested in 'open court'.

These sorts of problems are not new, and in Europe this was recognised by the tackle trade association, who now run a certification scheme for all monofilament suppliers to join, provided they allow their lines to be tested again stated values in an independent laboratory appointed by the trade association. It has obviously over time weeded out those that are very 'enthusiastic' with their sales literature, and at the end of the day, both the trade and the consumer win.

The troubles with braid is that not all products are equal, various 'mixers' are added by some, while others use pure dyneema or spectra. Then their are the difficulties of measuring, for as it is a woven material, it is very difficult to 'mic' the diameter. As well as the fact that some manufacturers coat their woven braids. It all becomes a seriously difficult issue to control, and then institute any control criteria.

For myself, I strongly prefer the straight 'virgin' product, just woven grey threads, without any coatings – I'm not worried about noise in casting, just the performance. We use a locally braided product that is licensed from Dyneema the parent company, and we feel that we get consistant results from their product range. The rest are basically just selling with a lot of additional enthusiastic sales chat.

Just my thoughts – find a good brand that you like, and stick to it.


Cheers from sunny Africa


Jeri

[Keta]

I don't like thin Spectra and most of my reels have 60/65 or higher (I have some 200 and one reel has a section of 300) on them due to it's diameter not breaking strength.  My small kokanee and steelhead reels (Calcutta 51s and Curado 201s) have 30 on them due to their small line capacity.  I use 30 for serving when making topshots and use some Power Pro Ace hollow in 40lb on my Surfmaster and ABU reels but the hollow lays flat and does not cut my hands like solid does.