Warning - your backing might not be what you think it is

[plotkinms]

About a month ago a friend and officer of our fly fishing club bought some 30# Scientific Angler backing. Because he was going to use it for large fish he decided to test its breaking strength before loading it on his reel. He cut off a piece, tied loops in both ends, attached one end to an anchor point and the other end to a scale, then started to pull the line. To his surprise, and after repeated tests, the line (not the knots) broke at about 16 lbs. To make sure it was the line and not the scale he tested the scale with known weights.

After numerous correspondence with Scientific Angler and the place he bought the line and sending the line to Scientific Angler for evaluation it was concluded that the issue was the testing method. Scientific Angler tests with a machine that stretches the line VERY, SLOWLY (8”/sec).

I believe this could be a major problem if your using 20 lb class tippet may result in loss of a fly line et. al.

Last week I received 30# Rio backing and did my own testing. My tests showed the backing to break at 18 lbs. After discussing the matter with the store I bought the line from I received the following response:

"We have had a couple folks make similar comments about the backing not testing to the rating based on there home testing methods. We contacted the manufacturers and learned about their testing methods which involve a fancy machine that pulls the backing a a super slow rate (10" per minute) and sent some 30 lb backing that a customer tested breaking at 18 lbs. "

I called Rio and they confirmed what the vendor told me.

I realize that in the field it is rare to put 30 lbs stress on a line but it does happen and it would be nice if an angler could be sure their class tippet would break before any other part of the system.

I've been told Orvis tests differently and their backing breaks closer to 30 lbs. I guess I'll look into that next. If that doesn't work it's on to gel-spun, but that is a hole different set of problems.

[jbird]

Very interesting. Don't know of too many fishes that pull at a rate of 10"/ minute. I don't think I have ever boughg flyfishing specific backing. I typically use power pro or tuf line xp

[David Lee]

Interesting .

Good thing that , by the time backing comes into play ... there's a pile of stretch already in the system . If I had a digi scale handy , I'd try some Cortland Saltwater 36 Lb. - that stuff is huge !

D.~

[aaron]

I called Rio and they confirmed what the vendor told me.

Huh, I personally tested spools of our (RIO) backing today. We use an instron machine which is standard for any sort tensile strength test. The results had our #30 breaking at 32lbs+ at 12% stretch. With #20 the breaking strengths all exceeded 25lbs with 25% stretch. You'd have a hell of a time reaching those loads under a fishing situation.

[TaylerW]

I use hatch's backing. Got a spool a while back and this stuff is something....

[Ben Kobrin]

The only time I ever see my backing is when I load it on my reel.