hook corrosion?

[Philip]

Its an interesting concept & no way to prove your right or wrong but I think different people have different reasons they go fishing & not all are based on a deep seated primeval need to hunt..

One thing I am 100% sure about is my reasons for treating them with respect. Its not based on the need to sustain a food source. Its actually far more selfish than that...I just want to put it back to grow bigger so I can catch it again...

 

[geoffmaynard]

Phillip - we think alike. I'm selfish too, no altruism there - and that's why I'm concerned about deep-hooked or lost fish; because I want to catch them again, I don't want them to die.

 

[waggy]

Its an interesting concept & no way to prove your right or wrong but I think different people have different reasons they go fishing & not all are based on a deep seated primeval need to hunt..

One thing I am 100% sure about is my reasons for treating them with respect. Its not based on the need to sustain a food source. Its actually far more selfish than that...I just want to put it back to grow bigger so I can catch it again...

I think we're often not aware of the deep seated biological imperatives that drive us and that makes some of our behaviour chime out of tune with current social mores. But, when our backs are to the wall, we always fall back on them.

 

[Philip]

Geoff ...I dont want them to die either but I also want to preserve my right to go angling and angling means hooks in fish and there will ALWAYS be a inherent risk that some fish may die as a result.

Waggy... sorry but I am not sure what your talking about now.

 

[waggy]

Not to worry.
Does anyone know where I can get Hydrochloric acid?

 

[Philip]

Yes, you can get a 200L drum here => Hydrochloric Acid (HCL) : UK Chemical Suppliers, Buy Chemicals Online

....don't fall in !

 

[waggy]

Nice but I was thinking more like 200 ml.
Anyway; developments on the 2 batches of hooks , one in slightly acid tap water and the other in vinegar: The hooks in both were immersed at the end of October and until a week ago seemed none the worse for wear.
This morning they're both showing apparently sudden signs of disintegration. The points and barbs have fallen off, the circles being the most affected and the shanks are now showing definite signs of pitting and thinning. The bigger sizes seem to be more affected than the small stuff. Strange indeed.
I'll keep you bulletined.

 

[waggy]

Corrosion update:-
Size 2, fine wire Sakuma Manta long shank J hook, in malt vinegar, turned to putty this week and disintegrated. Size 4 robust circle hook in same container that had lost point and barb is still intact otherwise.

Size 6 fine wire eyed J hook in acidic tap water has lost point and barb completely.In same container, Size 13 fine wire Mustad that lost it's spade tabs at last report has lost its barb but not it's point. Also in same container, size 12 stainless Drennan wide gape eyed is still totally unaffected.

It's been 8 weeks since they were first immersed.Draw your own conclusions.
(The batch in lemon juice grew green fungus and dried out and that one was abandoned.)

 

[Jeff Woodhouse]

This is getting interesting Waggy. It could form part of proper research although soem will say it's not been under strict laboratory conditions and therefore doesn't count.

You were after hydrochloric acid to try that, but is that enough? Look at what Wikipedia says about gastric acid - "In chemical terms, it is an acid solution with a pH of 1 to 2 in the stomach lumen, consisting mainly of hydrochloric acid (HCl) (around 0.5%, or 5000 parts per million), and large quantities of potassium chloride (KCl) and sodium chloride (NaCl)."
So in addition to hydrochloric acid, you'd need to add potassium chloride and sodium chloride and no doubt this cocktail will increase the pwer to disolve metals quickly.

That's for a human, how about a fish? I wonder if the universaties have conducted any experiments like this. Bear in mind also, that we were talking at first about a hook left in a fish, in tissue! So is there any other force at work (like our white corpuscles) there that could help disolve a hook or expel it from the wounded area even quicker?

Whatever, what you have proved so far goes a long way to convincing me that fish can survive if a hook is left in them.

Might try some in Cillit Bang or Viakal, they're pretty strong in acids.


Another note: Lo Salt (from grocery stores) contains both potassium chloride and sodium chloride.

 

[waggy]

Cheers, Jeff.
It was only intended as a quick look to get some pointers on how a proper trial might be constructed. Water only was included to cover hooks in non vital areas that might not be affected by acids. I think in most spp, encystment may take place, which may protect all except immediately surrounding tissues from toxic contamination or, as you suggest, to digest any foreign body.
I intend to get some HCl in the new year to simulate stomach acid and , again as you've suggested, some strong alkalis, since any stomach lodged hook would necessarily be subject to an alternating battery of pH swings in a fish's stomach.
Not sure how I'm going to set this up yet since length of digestion time depends on meal size, I suppose.
I think I'll just keep it simple for a start - either acid or just strong alkali, although, in digestion, I think it's strong acid followed by neutralisation via alkali, so it's either acid or acid+alkali.
I think any proper study is obviously a job for a lab somewhere.
Any comment from anyone would be gratefully considered.

 

[geoffmaynard]

I think this is fascinating stuff.

A point to consider - does the acid in the vinegar deteriorate in strength if left in a container with a hook selection over weeks and months? I believe it could do. Perhaps the acid needs to be refreshed every week or so to better emulate a fish's digestion fluids.

 

[waggy]

I changed it at 6 weeks Geoff. So perhaps the process could have been driven a lot quicker with weekly changes to refresh the anions. It's worth a try.
I'm no chemist so I'll have to come up to speed.

 

[yellabelly78]

Just a thought for your experiment, you could try some hooks in caustic soda (ph13-14) so you cover the strong alkalis.
If you wanted to get even more scientific about it, ideally you'd want to put the same type of hook in a control substance, say sterile water, so that you can then compare whether the test substance is having a greater or lesser effect than the water.
Another substance that might be worth testing, and probably a bit nicer to handle than hydrochloric, would be citric acid (ph2). I'm not sure what ph cheapo lemonade or coke is but I used to use it for cleaning glue off floors at work!!

 

[waggy]

Thanks Yellabelly, good advice. Cleans glue off, eh. It's well known to rot tooth enamel.

 

[yellabelly78]

its amazing how corrosive it is, we'd remove carpet tiles and the old dusty crusty glue would come straight off after a 5 min soak in Asda Value lemonade. Certainly puts you off drinking it! I clean old motorbike parts in it too!
Good Luck with your experiment

 

[waggy]

Corrosion bulletin:
Not had time to do anything due to 2 unplanned A&E Angina visits and hideous vertigo.
But, it's now 4 months since first hook immersions and several changes of malt vinegar or water later.
Water samples:- Size 13 fine wire mustad has at last fallen apart to the touch.
size12 Drennan, eyed, wide-gape, stainless, barbless: still intact but blunted and rusted at last.


Malt vinegar sample:- Size 4 robust circle hook has broken in pieces to the touch.

I seem to think that all hooks except the Drennan would have either rotted out of a fish's flesh by now (fate in stomach still open to speculation) or the fish would have died, depending on the site of hook insertion.
I saw something on Matt Thingummy's Total fishing programme about special quick-rot hooks for tag and release shark fishing. Anyone know anything about them?

 

[waggy]

Final corrosion bulletin:
Well folks, looks like the end of my little experiment which started with various hooks being immersed in various liquid media in October last.
The final non-stainless hook, a robust size 6 J hook, immersed in Anglesey tap water , has finally given up its steely ghost and dissolved.
That leaves the Drennan spade stainless which, although generally sound is showing advancing signs of imminent failure.
So I think I'll leave it there, having established that, despite what some pundits opine, hooks do not 'rot out' in a matter of days but rather in months. As I write, that's 6 months with one hook still to reach the advanced stage of rot that it would probably have to attain in order to be shed.

My own conclusion from this is that to aid faster shedding of hooks, use barbless hooks if the fish are to be returned and use the crappiest, fastest rotting hooks available to speed up the shedding time.
Anyone else like to comment?

 

[Jeff Woodhouse]

It's been useful that, Waggy, thanks.

Of course, we still don't know just how much and what type of acid a fish can muster in it's gut to quicken the process, but the fact that they disolve in time does tell us something.

And would you believe, they have now developed - BIODEGRADABLE line! YES, it's true, it stays pretty fresh and strong for one year and then starts to degrade completely in 5 years - as opposed to 60-100 years for normal line.

 

[waggy]

Thanks for the biodegradable line news Jeff. I still haven't managed to source the quick-rot hooks I mentioned earlier. They are used to catch tag and release gamefish like Marlin and sharks and left in situ when the tag is placed and the line cut..

 

[laguna]

It's been useful that, Waggy, thanks.

Of course, we still don't know just how much and what type of acid a fish can muster in it's gut to quicken the process, but the fact that they disolve in time does tell us something.

And would you believe, they have now developed - BIODEGRADABLE line! YES, it's true, it stays pretty fresh and strong for one year and then starts to degrade completely in 5 years - as opposed to 60-100 years for normal line.

Interesting thread.
I have some notes somewhere which suggests as low as pH2 in some species which makes you appreciate just how resistant their stomach lining must be

Stainless steel hooks (containing chromium alloy) do not readily dissolve in the stomach acids of fish when they are gut-hooked.

Rated hooks as being corrosion resistant say 1-10 could allow anglers to make up their own minds, but at the end of the day this might be construed as been "weak" and who dare print that on the label?