Brine for Quench

[Daniel Fairly Knives]

I have some 1095 I'd like to use and want to know if brine would be a good quenchant.

I don't have any problem saving up for some Parks 50 or the equivalent if it is better. I don't wan't to compromise on my knives.

 

[Robert Mayo]

Well if you are not willing to lose any knives to the quench gods during your learning curve with brine i would suggest you hold off until you can get some fast oil.
That tink gives you a sick feeling!
Bob

 

[Stacy E. Apelt - Bladesmith]

What Robert said.

Although this brings up an interesting thing......does high altitude noticeably affect a quench by lowering the vapor jacket temperature.

 

[Daniel Fairly Knives]

Well if you are not willing to lose any knives to the quench gods during your learning curve with brine i would suggest you hold off until you can get some fast oil.
That tink gives you a sick feeling!
Bob

I'm going to keep saving up then, that's what I figured.

 

[Daniel Fairly Knives]

What Robert said.

Although this brings up an interesting thing......does high altitude noticeably affect a quench by lowering the vapor jacket temperature.

I could see it doing that, high altitude really effects things a lot.

Water here boils at around 200 degrees if I remember correctly.

 

[Danbo]

Not to say that you couldn't use the brine. Some of the coolest Hamons have come from water/brine quenches. Just accept the fact that you'll probably crack 2 blades to every one you don't(ratio might even be worse). I didn't/don't even try to water quench a blade; I got the Parks 50.

 

[Kentucky]

Theres a real earning curve to water quenching..Ive felt that *tink* before :jerkit: Ive also see what a fantastic hamon that can come from a water quench. We dont water quench all the time but we have pretty fair success with it now. A few things we do do lessen then danger
*Leave the edge thicker
*Finish down finer than normal, maybe 320..Leave no scratches for stress risers
*Warm(*120 or so) clean rainwater, no tap water..
*Interrupted quench
*RUN to a preheated temperering oven
You still must be willing to accept the chance of a cracked blade but if you take precautions you wont crack every other blade..

 

[jdn181]

I typically use Brine to quench my 1095 blades. Made 6 blades so far and lost 2 to cracking - which I discovered why and it was my fault.

1st cracked blade: Thinned the edge too much and didn't remove a couple of scratches that caused stress raisers. I leave my edges at 0.040" min now and sand to 320 at the lowest grit - scratch marks from ricasso to tip, not spine to edge.

2nd cracked blade: The layer of refractory cement I put on the blade for a hamon separated from the metal during quench, causing the whole blade to harden and caused all sorts of cracks. I wrap all my clay with iron wire now just as insurance.

Thanks to Bladsmth I've got my process down pretty well:

Pre-Treatment
---------------------------
Prior to any quenching I normalize the blade thru 3 cycles - Cycle 1 I heat to just above magnetic (1420 to 1450deg) and let cool. Cycle 2 I heat to just below magnetic and let cool (1350 to 1370). Cycle 3 I heat to a dull red (by my eyes) and let cool (1250 to 1300).

Once the blade is back to ambient temperature I'll round out the edge a bit (a square edge is also a stress raiser) and sand it 320 or 400g. Then the clay coating goes on - but only 1/16" thick at most anywhere on the blade, and any pattern I put in the clay is symmetrical (shape and position) on both sides of the blade!

Quenching
-----------------------------
1) Set the tempering oven to 400deg to pre-heat

2) Put blade in the propane forge and fire it up, letting it come to ~1450deg (I use a muffle tube to keep the burner flame from impinging on the metal). As an aside I haven't tested it, but I hear the amount of scale is reduced if you put a peice of wood in the muffle tube to burn up some of the available oxygen).

3) I prepare the brine by removing 2.5gal of brine from the 5gal brine bucket. I heat this 2.5gal in a pot on my stove until it hits about 120 to 140deg. (I use a thermocouple to measure). When it's up to temp I dump the pot back into the brine bucket (temp of brine in bucket is about 70deg) and when mixed together I get a total bucket temp of about 100 to 105. The bucket is then placed next to forge for quenching.

4) By the time the brine bucket is prepared the temp of the forge and blade is somewhere around 1350. (My thermocouple and PID controller measure the temp of the forge and not the muffle tube, so when it puts the burner on idle after the sensor hits 1450 the temp in the muffle tube is around 1350. This allows me to increase the temperature gradually and creep up on 1420 to 1450 pretty easily. As the temperature creeps up I remove the blade and test magnetically. If it isn't there it goes back in for 30sec or so before I test again. I continually test until the blade is just non-magnetic but becomes magnetic again within about 5sec of removing it from the forge. (I use a really strong magnetic to make sure the blade is completely non-magnetic and not just on the surface. I usually pull the blade out about 4 to 5 times right around non-magnetic and letting come down to magnetic again so I can get an idea of how fast it's cooling in the ambient air, as well as making sure I'm as close to the non-magnetic as possible. When I tell myself that I'm ready I'll pull it out one last time, do a quick magnet check, and plunge it into the brine blade down, tip first. I count to 5-mississippi, pull the blade out and count to 3-mississippi, then plunge it back into the brine until cool. I don't move the blade around, just leave it submerged in one place. (Moving the blade can cause one side of the blade to cool faster than the other, cause unequal stresses which in turn promote cracks).

Tempering
-------------------------------
1) When the blade is cool to the touch (140deg or lower) I clip all the wires wrapped around the blade and "knock off" the clay...though usually the clay just sloughs off after the wires are removed.

2) The blade then goes into the 400deg tempering oven for 2 hrs, then air-cooled for 30mins, followed by another 2hr tempering cycle and then cool-down.


Examination
-----------------------------
After the blade is cool to the touch again I sand with some 320g to remove all the left over clay bits and give it a quick dip in a 50/50 solution of Ferric Chloride and water. This brings the hamon out a little so you can see whats there and if it's worth developing further.

I also give it a quick crack test by lightly hold just the tip of the hand (rear-most part of the blank) and then light tap the blade with something metal. If the blade is crack free it will ring at a certain pitch and the ring will fade slowly. If there's a crack you'll get the same pitch of ring, but it will fade quickly and sound dull (best way I can describe it). If it rings like a bell it's good. If it tinks and doesn't ring much at all then it's turned into a smaller blade (if the scrack can be located) or into the scrap pile it goes.

 

[Daniel Fairly Knives]

Theres a real earning curve to water quenching..Ive felt that *tink* before :jerkit: Ive also see what a fantastic hamon that can come from a water quench. We dont water quench all the time but we have pretty fair success with it now. A few things we do do lessen then danger
*Leave the edge thicker
*Finish down finer than normal, maybe 320..Leave no scratches for stress risers
*Warm(*120 or so) clean rainwater, no tap water..
*Interrupted quench
*RUN to a preheated temperering oven
You still must be willing to accept the chance of a cracked blade but if you take precautions you wont crack every other blade..

Thank you, there are some great tips there!

 

[Daniel Fairly Knives]

I typically use Brine to quench my 1095 blades. Made 6 blades so far and lost 2 to cracking - which I discovered why and it was my fault...

Thank you for taking the time to show us your process, there is a lot to be learned there. :thumbup: