Help me understand a knot strength anomoly

[Deadphishspread]

While doing knot strength tests I discovered that a particular terminal knot tied in 4 and 6 pound mono holds very well, but if tied in 8, 10, and 12 pound mono it fails miserably.  

 

I used a variety of snap and swivel sizes. When I tied this knot with 4 and 6 pound line to very small diameter wire snaps and swivels it usually held above the stated line strength. The same line tied to larger diameter wire snaps and swivels broke at the knot below the line strength. 

 

When I tied the knot using 8, 10, and 12 pound line to either small or larger diameter wire snaps and swivels it failed below line strength. So it seems like it's a great knot if used only for tying light line to small diameter wire snaps/swivels/eyes. 

 

My question is, what properties of mono are demonstrated by this experiment? 

 

The knot I was tying is a slight variation of the improved clinch. It's not a known knot; I can demonstrate it if there's any interest in such a near-useless knot.  

[Deadphishspread]

I think what I'm asking is: Do different tensile strength nylon monofilament lines have the same knot strength (as a ratio of line diameter/force required for knot failure) when tied to correspondingly larger diameter wire eyes, using the same knot? If not, why? 

[J Francho]

It depends more on the person tying the knot. 

[bulldog1935]

If you tie 8-lb and 20-lb mono together in any single bend knots, and pull until they break, the 8-lb will cut through the 20-lb. 

A small metal wire will certainly do the same thing. 

[WRB]

Do you have the same problem with a standard improved clinch knot? Small diameter line like 4-6 lb using the improved clinch knot needs 7 twists, 10-12 lb use 5 twists.

Tom

[T-Billy]

15 minutes ago, WRB said:

Do you have the same problem with a standard improved clinch knot? Small diameter line like 4-6 lb using the improved clinch knot needs 7 twists, 10-12 lb use 5 twists.

Tom

I was thinking along the same line. I use a Trilene knot with mono. 4 twists for 8# and below, and 3 for 10# and up.

[QED]

2 hours ago, WRB said:

Do you have the same problem with a standard improved clinch knot? Small diameter line like 4-6 lb using the improved clinch knot needs 7 twists, 10-12 lb use 5 twists.

Tom

By twists, do you mean crossings vs full turns?  With respect to improved clinch knots, I've been using 5-1/2 turns (i.e., 11 crossings) for 2-8# test mono without any issues.

[papajoe222]

I'm thinking you need to add turns, when using heavier line, to avoid slippage. Is the line is breaking at the knot? If that's the case, it's likely you're not lubricating the knot sufficiently.

Lastly, how well does this 'not well known' knot fare under real life use with heavier line?

[newapti5]

As others mentioned, the thicker the diameter is, the stiffer the line is, and the harder to do turns and tie knots. From my personal experience, to make sure the improved clinch knot is well tied on thicker lines, you'll need to do less turns, make sure the knot is well lubricated, and tie it slowly to make sure the knot is neat and tight, nothing twist or loose.

[Hulkster]

i switched to the palomar knot over the trilene or fishermans knot a few years ago. way easier to tie, less finnicky and stronger. 

[moguy1973]

On 10/19/2021 at 6:57 PM, WRB said:

Do you have the same problem with a standard improved clinch knot? Small diameter line like 4-6 lb using the improved clinch knot needs 7 twists, 10-12 lb use 5 twists.

Tom

I have this question too.  Why the variation of the standard knot?  What is the variation and is it believed to help?

 

Personally, I don't use anything except for the Palomar anymore, unless I'm fly fishing with really small flies where I can't put two lines through the hook eye, and then I use a uni knot.

[PressuredFishing]

On 10/19/2021 at 12:50 PM, Deadphishspread said:

While doing knot strength tests I discovered that a particular terminal knot tied in 4 and 6 pound mono holds very well, but if tied in 8, 10, and 12 pound mono it fails miserably.  

 

I used a variety of snap and swivel sizes. When I tied this knot with 4 and 6 pound line to very small diameter wire snaps and swivels it usually held above the stated line strength. The same line tied to larger diameter wire snaps and swivels broke at the knot below the line strength. 

 

When I tied the knot using 8, 10, and 12 pound line to either small or larger diameter wire snaps and swivels it failed below line strength. So it seems like it's a great knot if used only for tying light line to small diameter wire snaps/swivels/eyes. 

 

My question is, what properties of mono are demonstrated by this experiment? 

 

The knot I was tying is a slight variation of the improved clinch. It's not a known knot; I can demonstrate it if there's any interest in such a near-useless knot.  

Most knots are stronger than the tier and failure comes usually from the person tying a bad knot or getting snagged and pulling, not the knot itself.

[MickD]

There is also the possibility that your 4 and 6 pound test lines are actually higher in pound test than the label while the other lines may not be higher than their label resulting in the first testing higher than label and the others lower than label?

 

Are the 8's and 10's Vanish?

 

Are all lines the same maker and model lines?  If not then you could have a couple lines with superior knot strength and a couple with inferior knot strength.

[Deadphishspread]

Thanks for the replies, folks. 

Bulldog1935, yep, that's what led me to experiment with different knots and variations. The wire eye is smaller in diameter than the line. It cuts like a knife. 

 

Tom and T-billy, I experimented with the number of twists but maybe not as thoroughly as I should have. I used 7 wraps for 6 and 4 pound test; 5 wraps for everything heavier. I did this with the improved clinch, the trilene knot, and the modified I.C. 

 

QED, by wrap I mean full wrap around. Not twisting the eye but wrapping tag completely around standing end. 

 

papajoe222, I was careful to lubricate every knot. I used saliva but maybe dry fly dressing would've led to a different outcome. I've not used the knot on the water yet. 

 

newapti5, big 10-4 on that. Ironically, the modifiied version uses the knot's natural tendency to twist around itself. This is why I question if smaller diameter mono has a different intrinsic property from larger diameter mono. The lighter line seems to twist around itself better. 

 

moguy1973, a few weeks ago I caught a big cutthroat on a tube jig. I was using 6 pound trilene xp tied to the jig with a trilene knot. As I netted the fish the knot broke. I vowed to get to the bottom of this near disaster. During pull testing with a digital scale the trilene knot failed well below line strength about 30% of the time. This poor performance seems to happen with all the various lines I tested. During testing the variation seems much stronger and easier to tie consistently, but only when used in lighter line (4 and 6 pound). It really sucks when tied in or above 8 pound test. 

 

PressuredFishing, yup.

 

MickD, as much as I hate to admit it, I think you nailed it. I simply allowed too many variables. Firstly, the cheap $45 scale I used is probably not very accurate, and I didn't verify its accuracy with known weights. I used different brands and "lines" of line. Nothing was consistent. If I can access a good scale I'll do it over again properly. 

 

 

 

 

 

 

 

 

 

 

[Deleted account]

11 hours ago, Deadphishspread said:

 as much as I hate to admit it, I think you nailed it. I simply allowed too many variables. Firstly, the cheap $45 scale I used is probably not very accurate, and I didn't verify its accuracy with known weights. I used different brands and "lines" of line. Nothing was consistent. If I can access a good scale I'll do it over again properly. 

Never mind...

[WRB]

You can achieve Consistent testing using a accepted test procedure that uses calibrated equipment. There is a big different between tensile strength and impact strength, rate of applying the pulling force is extremely important.

At the end of the day it’s actual fishing experience that counts. 

My suggestion is learn to tie knots properly without stressing the line during clinching tight.

Nearly all premium monofilament should achieve 100% knot strength.

I use the San Diego Jam not and Palomar knot for all fresh water lines tied direct to hooks, snaps and lures.

Tom