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Author: Subject: nylon string density : pyramid vs. kurschner
juju
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[*] posted on 4-14-2015 at 02:45 AM
nylon string density : pyramid vs. kurschner


Hi,
my string dealer told me last week that nylon strings from Kurschner are more dense than Pyramid ... for example, 0.625mm from Pyramid could be equivalent to 0.60mm from Kurschner ... I thought that all nylon strings were equivalent ! No ?
Anyone has the nylon string density value from Pyramid and Kurschner ??
Best
juju.
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jdowning
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[*] posted on 4-14-2015 at 11:59 AM


It depends upon the particular 'Nylon' composition used by the string maker which might range in density from about 1.04 gm/cm³ to about 1.12 gm/cm³ - 1.08 gm/cm³ might be a good average value for string calculation purposes. Special nylon compositions may have higher densities - like 'Nylgut' with a density of about 1.3 gm/cm³ which is close to that of gut.

The plain nylon Pyramid string of 0.625 mm diameter has been 'rectified' - that is ground to a precise, smooth cylinder. The 0.60 plain Kurschner string may not be rectified (?) and so - dependant upon manufacturing tolerances - may be slightly oversize so approaching the diameter of the rectified Pyramid string. In which case there would be insignificant difference between the densities of the nylon used by Pyramid and Kurschner.
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Brian Prunka
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[*] posted on 4-14-2015 at 01:02 PM


I don't think that "nylgut" is a formulation of nylon at all. It is simply a proprietary term for another material.

The bigger issue is that all nylon is manufactured by a small number of chemical factories. Kurschner indicates "Dupont" on their packaging, which could mean that they get their nylon from DuPont or simply that they are using the general term (since DuPont invented nylon). BASF is another manufacturer, based in Germany and it may be that Pyramid uses their Nylon. I don't know but there is a consistent formula for nylon that shouldn't vary much at all from factory to factory.
I've never been able to get reliable information about who makes the nylon for whom, and it should be all rather similar.




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jdowning
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[*] posted on 4-15-2015 at 04:46 AM


These days 'nylon' is a generic term for any 'aliphatic polyamide' molecular structure plastic including those blended together to make co-polymers with differing physical properties. There are a number of companies worldwide that manufacture these plastics apart from the originals Dupont and BASF and I suspect that none has patent/copyright claim on the word 'nylon' although they likely do on specific formulations that they have developed. These companies can supply the 'raw' product either as a ready made extruded monofilament string (that might undergo further processing by a string manufacturer) or as granulated material that may be further compounded and extruded by a string manufacturer to meet their objectives for specific string physical properties - such as density, elasticity, tensile strength, durability etc.

I don't know the composition of the Aquila 'nylgut' strings but suspect that they are some co-polymer formulation of aliphatic polyamides i.e. 'nylon'?

I could deduce the density of nylon used by 'Pyramid' from their string tension tables of 1970's vintage (1.04 gm/cc ?) but doubt if that is the grade of nylon that they now use. Pyramid then used to sell 'Perlon' as a tied fret material- that I assume is a softer more flexible aliphatic polyamide - made by a German company (BASF ?) who may also then have been their supplier for instrument string nylon?

But, who knows as I doubt if most instrument string manufacturers today will reveal the exact formulation or source of their string materials.

P.S. I have deduced the density of the 1970's vintage plain nylon strings - from the Pyramid published string tension tables - confirming it to be about 1.04 gm/cc
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Brian Prunka
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[*] posted on 4-15-2015 at 07:16 AM


Nylgut has been hypothesized to be Polyoxymethylene, which I believe is aliphatic polyamide.

"Nylon" these days mostly refers to Nylon, at least when discussing strings. Usually Nylon 6 or Nylon 6-6 or a closely related formula. Since "nylon" refers to a relatively narrow class of plastic strings, it is useful to distinguish between that class and other classes. There are a number of manufacturers, but still a relatively small number, especially for the full range of products (strings of course not being the only or even primary form of nylon produced).

Perlon is nylon 6, which IG Farben developed to bypass DuPont's patent. BASF is a successor to IG Farben, I believe due to anti-trust regulation. You are most likely correct that it was also their string material at the time.





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[*] posted on 4-16-2015 at 12:08 PM


On further investigation 'Perlon' like 'Nylon' comes in various compositions - Perlon N is equivalent to Nylon 6, Perlon T is equivalent to Nylon 66 and then there is Perlon L with density 1.15 to 1.25 gm/ml and Perlon U with density 1.2 to 1.25 gm/cc.

Pyramid sell 'Perlon' in 50m spools for frets so is likely not suitable as a string material (softer and more elastic?) - Perlon U perhaps but they don't say. I have never tried it for frets but have used 'nylon' fishing line instead (but prefer the more costly gut).

Nylon 6 has a density of about 1.08 g/ml (or grams/cc) and Nylon 66 a density of 1.14 g/ml. Deducing the density of Pyramid monofilament Nylon strings - this time from their string calculator data - I arrive at a density of about 1.08g/ml which equates to Nylon 6 (as does a density of 1.04 g/ml for purposes of string calculation).

Kurschner nylon strings are apparently rectified so to return to juju's original question if a Kurchner 0.6 mm rectified Nylon string is equivalent to a Pyramid 0.625 mm rectified Nylon string then Kurschner are using a material of string density of about 1.14 g/ml which equates to Nylon 66.
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juju
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[*] posted on 4-20-2015 at 12:44 AM


Thanks for all your replies !

I often use the pyramid tables you put on the forum, they are very useful.

Do other manufacturers have equivalent tables for their strings ?

Best.
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[*] posted on 4-20-2015 at 07:00 AM


Both Pyramid and Kurschner sell useful string calculator slide rules at reasonable cost that are more convenient and provide more information than tables (although not string density information).
The other way to calculate string dimensions and tension is to use the free string calculators available on line - Arto Wickla's and Oliver Wadsworth StringCalc32 - both for monofilament strings (not composite wound strings). Alternatively there is Paul Beier's string and fret calculator software (free to download and try) that does cover wound strings by the well known manufacturers like Pyramid and Kurschner. This is now in version 2 that is a considerable improvement over the earlier version that I tested a few years ago. Worth a try and not costly to purchase (10 Euros?)
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[*] posted on 4-22-2015 at 06:14 AM


Hi Guys,
these two Brands uses the same Du Pont polyammide.
Tinex 6-12.
so they have the same density: 1.04
The nylon useful for music is Tinex only
I mean that it is not possible to use Perlon because it is dull (whose density is 1,16).
Mimmo
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Brian Prunka
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[*] posted on 4-22-2015 at 06:15 AM


Thanks for the info Mimmo!



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