Retempering Hooks

[mark poulson]

I have a bait which requires me to open up the hook.  I'd like to be able to retemper it afterwards, so it won't open up on a fish.

Does anyone here know how to do that, or if it is even possible?

[wchilton]

Are you talking about opening the eye of the hook or the bend?  Hook eyes are pretty strong and not likely to open.  Some east coast fishermen open up the eye on trebles to attach to the lure and just bend them back shut and don't have any problems.  If you're talking about having to straighten out the bend of the hook and then put back, I'd first test a hook on a scale and see how strong it is after you mess with it.  You might find that you don't need to re-temper.  "Tempering" is a word that gets misused a lot.  The actual "temper" process is a heat treatment after "hardening" to make steel less brittle.  The overal heat treatment for steel generally starts with heating to red hot (actual temperature here can be important but for many steels, a "cherry red" color is a good indicator), then the steel is hardened by "quenching" in either water or oil and that's what hardens the steel.  After that, a re-heating to somewhat lower temperature followed by more gradual cooling will "temper" the steel by reducing hardness enough so that the steel is no longer brittle.  That's the basic process.  Different steels/alloys require different treatments so things could vary if the hook is made of something exotic.  That much heat around a finished lure could be problematic.  If you find that the hook is actually weakened, first thing I'd try is to "work harden" the bend with a flat hammer so it looks like a forged hook (slightly flattened along sides of the bend).

[dochollow]

mark, I have no expierence heat treating hooks, but I am a 30 year tool & die maker & have knowledge of heat treating tool steels.

to be able to reheat treat a hook you would have to know exactly what kind steel it is made of,  then look up the parameters for

heat treating said steel. I don't think the average person has the equipment (heat treating oven) to do this as it should be done.

some tool steels require a temperature of 1800 deg.

[Mattlures]

Heat up the hook bend until its red. Bend it out to where you want it to be and then dip in cold water. This works on titanium wire too.

[RayburnGuy]

Heating metal to a "cherry red" and then quenching it in water, or oil, is known as "case hardening". This results in a hard outer shell while the interior of the metal does not reach the same hardness. To actually "heat treat" metals of various kinds they are brought up to a certain temp and then held there for a given amount of time depending on the specific makeup of the material and the amount of hardness your shooting for. This process results in a metal that is hard, but brittle. Reheating at a cooler temp and sustaining it for another given amount of time takes the brittleness out of the material. These processes require an oven (furnace) that is capable of reaching somewhere around 1800 degrees F. and holding it there within a given set of parameters.

 

I've had some luck heating up some hooks, bending them and then quenching them while others would break with nothing more than hand pressure. The only way to find out if the hooks your wanting to bend will accept this is to give them a try Mark. Just remember that hooks heat up quickly and cool down quickly which will have an effect on whether it works or not. You can heat the eye of a hook cherry red and it will start to cool and turn back to black before you can even get a set of pliers on it. It would be best if you could heat it up and keep it in the fire while your bending it. Then you could let it cool before you performed your modification. After your mods are done you would then heat it back to cherry red before quenching it. When quenching I prefer oil although I've used both water and oil. Can't say with 100% certainty, but it's my thinking that the burning oil can add a small bit of carbon back to the steel to make the surface harder.

 

Depending on the type of hook it may not require heating to bend it. When building trot lines with stainless hooks I just open them cold with a pair of vice grips and a pair of channel locks. And the stainless hooks I use can be anywhere from 6/0 to 9/0 so you have to grunt a bit when opening these.

 

good luck,

 

Ben

[BobP]

It may depend on how the hook is tempered at the factory.  I cut the line tie of less expensive Mustad trebles, bend them out, then put them on Silver Buddies and close them with pliers.  No heat required.  If I try the same with Gamakatsu or other higher quality hooks, they break.  Heating steel cherry hot often lets you bend it without breaking but tempering steel is a two part process in which it is first heated to high heat, then quenched quickly.  It is brittle at this point, so you need to reheat it to a lower temp and cool it slowly to relieve the internal stresses created by the first heating.  If you just do the first high heating, you'll probably break the hook when trying to close it again.

[mark poulson]

I am opening up the hook point, so I have a much bigger bite.  I tried it with Owner hooks, and they broke.

So I went on TW and ordered some other 60 degree extra wide gap jig hooks.

Right now I'm bending out the point of a VMC 60 degree jig hook.  The hooks bend without breaking, but I'm worried that they will open up even more when they get bitten.

If my design works, and hooks opening becomes a problem, I'll probably experiment with tempering them, but that's a problem I'll deal with if it comes up.  

Or, worst case scenario, one fish, one hook.

First I have to get bit!

[BobP]

VMC hooks are not tempered to the extent that Japanese hooks are.  Will they bend out further?  Maybe - depends on the force applied to them.  Rather than try tempering them if that happens, I'd try a VMC or Mustad hook with heavier wire.

[mark poulson]

Are you talking about opening the eye of the hook or the bend?  Hook eyes are pretty strong and not likely to open.  Some east coast fishermen open up the eye on trebles to attach to the lure and just bend them back shut and don't have any problems.  If you're talking about having to straighten out the bend of the hook and then put back, I'd first test a hook on a scale and see how strong it is after you mess with it.  You might find that you don't need to re-temper.  "Tempering" is a word that gets misused a lot.  The actual "temper" process is a heat treatment after "hardening" to make steel less brittle.  The overal heat treatment for steel generally starts with heating to red hot (actual temperature here can be important but for many steels, a "cherry red" color is a good indicator), then the steel is hardened by "quenching" in either water or oil and that's what hardens the steel.  After that, a re-heating to somewhat lower temperature followed by more gradual cooling will "temper" the steel by reducing hardness enough so that the steel is no longer brittle.  That's the basic process.  Different steels/alloys require different treatments so things could vary if the hook is made of something exotic.  That much heat around a finished lure could be problematic.  If you find that the hook is actually weakened, first thing I'd try is to "work harden" the bend with a flat hammer so it looks like a forged hook (slightly flattened along sides of the bend).

 

wchilton,

I'll give the hammer forging a try and see if that works.  Thanks for the idea.

Heating metal to a "cherry red" and then quenching it in water, or oil, is known as "case hardening". This results in a hard outer shell while the interior of the metal does not reach the same hardness. To actually "heat treat" metals of various kinds they are brought up to a certain temp and then held there for a given amount of time depending on the specific makeup of the material and the amount of hardness your shooting for. This process results in a metal that is hard, but brittle. Reheating at a cooler temp and sustaining it for another given amount of time takes the brittleness out of the material. These processes require an oven (furnace) that is capable of reaching somewhere around 1800 degrees F. and holding it there within a given set of parameters.

 

I've had some luck heating up some hooks, bending them and then quenching them while others would break with nothing more than hand pressure. The only way to find out if the hooks your wanting to bend will accept this is to give them a try Mark. Just remember that hooks heat up quickly and cool down quickly which will have an effect on whether it works or not. You can heat the eye of a hook cherry red and it will start to cool and turn back to black before you can even get a set of pliers on it. It would be best if you could heat it up and keep it in the fire while your bending it. Then you could let it cool before you performed your modification. After your mods are done you would then heat it back to cherry red before quenching it. When quenching I prefer oil although I've used both water and oil. Can't say with 100% certainty, but it's my thinking that the burning oil can add a small bit of carbon back to the steel to make the surface harder.

 

Depending on the type of hook it may not require heating to bend it. When building trot lines with stainless hooks I just open them cold with a pair of vice grips and a pair of channel locks. And the stainless hooks I use can be anywhere from 6/0 to 9/0 so you have to grunt a bit when opening these.

 

good luck,

 

Ben

 

I never considered sst hooks.  Another idea to explore.  Thanks

[mark poulson]

I'm shying away from trying to heat treat the hooks, thanks to all the advice here.

I'll concentrate on getting bit first, and then cross the stronger hook bridge when I come to it.

Thanks for all the help.

[wchilton]

The way you describe it with the hook weakening when you open it up is not something that heat treating or forging will help.  The process of opening up the point is either stressing the steel or work hardening it (just like forging with a hammer would).  Try starting with a more flexible hook and then do the hammer forging if you need more strength after its been shaped.  Normally what you would want to do is shape the steel when it is SOFT and then heat treat or work harden when it has its final shape.  You could also try to soften the steel on your hooks before bending it and then forge/work harden when cool.  You'd need to heat it up red hot and then let it cool gradually to soften the metal (this is called annealing).  Like someone said before, hooks are thin so they heat/cool pretty fast.  You could try putting them on an electric stove burner (the coil type that turns red) to heat them and then just leave them on the burner to cool.  Then bend to shape (they should bend easily), then work harden/hammer to strengthen along the bend of the hook.

 

One other thing.  Heating/cooling like that and bending can mess with the finish and hooks will rust more easily

[mark poulson]

The way you describe it with the hook weakening when you open it up is not something that heat treating or forging will help.  The process of opening up the point is either stressing the steel or work hardening it (just like forging with a hammer would).  Try starting with a more flexible hook and then do the hammer forging if you need more strength after its been shaped.  Normally what you would want to do is shape the steel when it is SOFT and then heat treat or work harden when it has its final shape.  You could also try to soften the steel on your hooks before bending it and then forge/work harden when cool.  You'd need to heat it up red hot and then let it cool gradually to soften the metal (this is called annealing).  Like someone said before, hooks are thin so they heat/cool pretty fast.  You could try putting them on an electric stove burner (the coil type that turns red) to heat them and then just leave them on the burner to cool.  Then bend to shape (they should bend easily), then work harden/hammer to strengthen along the bend of the hook.

 

One other thing.  Heating/cooling like that and bending can mess with the finish and hooks will rust more easily

 

Thanks for the additional information.  The more I learn about it, the less tempted I am to try to do it.