Robb Gunter's Super Quench

Wayne Coe

Forum Owner - Moderator
No, I did not misspell Robb.
I have been using Super Quench for several years. When I first started blacksmithing I got into carving heads, dragons, wizards, horse heads, etc. My wife has horses so we have plenty of horse shoes around. I started carving horse heads on the heel of half of a horse shoe and forging a letter opener blade on the other. I was quenching them in water and not drawing a temper. They would sell for about $25.00. After all horse shoes are made of mild steel. One day I thought about how much work I put into them for a $25.00 return. What if I quenched them in Super Quench? I started doing that and making a leather sheath and selling them for $125.00 and selling more of them. Last year I sold 6 at the blade show. My wife carries a Case Equine knife and I sharpen it more often than I do my Super Quenched mild steel knives. I believe that the reason my knives sold well is that 1. there are horse people at the Blade Show , 2. there was nothing else at the show anything like them. I am not advocating using mild steel for a good knife steel, it is something to think about. And BTW everyone was told that they were made of mild steel.

Well 'nuff of that stuff, here is the info on Super Quench:

Jet-Dry (or whatever you use for a rinse agent) does something chemically to the surface of the steel. It allows the salt in the mix to start attacking it as soon as it hits the air - make sure you have a LOT of clear water to rinse in ready at hand. These surfactants are wetting agents. They break down the surface tension of water allowing it to make contact with a material. We've all dipped a cold piece of metal in water and seen a bubble-like "skin" form with dry metal under it. This is surface tension trapping a layer of air, it makes a fair heat shield. In a quench, steam will form a similar surface "skin" and prevent full contact with the water, insulating the steel from a proper chill. Wetting agents prevent the "skin" from forming.
Detergents do a somewhat similar job, they're emulsifiers allowing oils and water to mix. This prevents any oily residues from the fire from forming a "heat shield" surface layer. The salt in the water raises the specific heat of the water and draws the heat from the steel faster.

Stir it up to get it moving before you quench. Don't quench anything with more than 45- 50 points of carbon. Will harden mild steel to Rockwell 42-45 (in spite of common wisdom that says you can't harden mild steel).

It's color coded - when you've exhausted the usefulness of the quench, it'll shift color from blue to green.
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www.shaklee.net
--------------------------------------------------------------------------------------------------------------------------------------------The following article came from:- http://lametalsmiths.org/news/robb_gunter.htm
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The Forgery School of Blacksmithings'
SOAP SOLUTION QUENCH
For mild and low carbon steels
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Whether its on the internet group "theforge", at ABANA chapter conferences, or just general discussion between a couple of friendly smiths, when the subject of Robb Gunter's "Super Quench" comes up, most of it is fact, but some of what is passed around is erroneous. Yes, there are some errors, but generally minor. There is often a great deal of disbelief as to the efficacy of this Super Quench. Here's what he had to say about it at the Guild of Metalsmiths 1997 Fall Conference:
Before the Bessemer process made it feasible to effectively control the amount of carbon in steel, blacksmiths generally had only iron or tool steel to work with. The Bessemer process gave the steel manufacturers the ability to produce steel in a variety of carbon levels. Mild steel (1005, 1018, and the like) was touted as the all purpose steel destined to replace wrought iron. The manufacturers claimed that it was also suitable for many tools, but that it should be quenched in a solution of sodium hydroxide.
At Sandia Labs, Robb and his cohorts experimented with this lye quench and, a bit to their surprise, they found that mild steel hardened considerably more that expected. Metallurgists and others will tell you quite readily that mild steel won't harden. It may get a little harder than if annealed, however it doesn't harden in the typical toolmaker's sense of hardening. Generally speaking, in a plain water quench you shouldn't expect to get more than Rockwell ratings in the low to mid 30's. Robb found that the sodium hydroxide quench resulted in average Rockwell ratings in the 43-45 range, with an occasional test result as high as 48.
So, Robb started using this solution at Sandia Labs, but installed a vented hood system over the quench tank. This stuff is pretty harsh and the need for a vented hood was a no-brainer.
Then OSHA arrived on the scene and insisted that the use of the sodium hydroxide solution cease. The result was that Robb and the Sandia Labs metallurgical lab crew went to work to find a replacement solution. It had to give hardness results comparable to the sodium hydroxide solution, and it should be bio-degradable if possible. The result of their experimentation was what is now generally referred to as Gunter's Super Quench. The formulation is as follows:
• 5 gallons of water (This a good volume to work with for quenching, and there are plenty of buckets and pails around just the right size.)

• 5 lbs table salt (plain or iodized, canning salt or rock salt, it makes no difference.)

• 32 oz Dawn Liquid Dishwashing Detergent Blue. 28 oz if the label says Concentrated.(Blue was chosen because that's what happened to be available at the moment. It was noted later on that as the solution deteriorated to the point that it should be disposed of, the color slowly changed to green. Hence, the blue detergent is recommended. Any other blue colored liquid detergent could work just as good.)

• 8 oz Shaklee Basic I. (The solution needs a surfactant to maximize contact between the solution and the piece being quenched. Amway Basic H will also work. Your local farmer's supply should be able to help here, as similar surfactants are used to facilitate the distribution of fertilizer in soil. In response to a question from the viewing stands, Robb said that just about any wetting agent should do, even the stuff photo film developers use. Just follow directions on amount of agent to be added to a given amount of water, then scale up or down to the 5 gallons of water used in this formulation.)
Heat your iron to 1550 degrees Fahrenheit, and quench. No tempering is needed.
So, he mixed up a batch right there in front of us and used it for his next demonstration. He took a piece of 1/2" 1018 and cut off a piece about 3" long. This piece was heated in the gas forge, and a cold chisel end was forged on to it. Robb heated the piece to 1550 (critical temp for mild steel), and quenched it in the solution. He then took his new "chisel" and proceeded to use it to cut almost through the parent bar. Then, he did it again. The cut bar and the chisel were passed around for all to take a good look at. The edge on the chisel was not deformed in any way. The top had not mushroomed, nor did it even show any evidence of having been hit with the hammer. But, so as not to mislead us, Robb said that a chisel of this type might be good for 7 or 8 cuts maximum. He recommends this quench for tools such as spring fullers and many treadle hammer tools/dies/fullers. He showed, and used, one such spring fuller that is made of mild steel and quenched in the solution. He has been using this particular fuller for several years with no ill effect. The fuller is unmarred, and the spring is still strong.
I was impressed, to say the least. I was not the only person there who was "wowed" by this little "trick". Robb said the quench is good for anything up to 50 points of carbon. Above this carbon level this quench should not be used.
The above is how I heard it from Robb Gunter at the Guild of Metalsmiths 1997 Fall Conference.
Dave Brown
Heritage 'Smithing
Heritage Hill State Historical Park
Green Bay, WI
 

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I've made superquench before and it's fun to play with. I played with rail road spikes mostly. It makes low carbon stuff hard. I couldn't get a blade of "higher" carbon steel to quench with out cracking but I didn't try that hard either.
 
It has been almost 6 months since I started this thread and since that time I have done some additional research and thinking on the subject.
In the article above Robb says that using the sodium hydroxide quench on 1018 resulted in average Rockwell ratings in the 43-45 range, with an occasional test result as high as 48.
I have not found any reference to the Rockwell rating using SuperQuench nor have I been able to find any reference to Rockwell hardness ratings using any other alloys of steel. It does say in the article, as well as in other places, not to use the sodium hydroxide quench on any alloy higher than 45 to 50 points.
This also applies to SuperQuench.
As many of you know, and as mentioned in the original post, I make knives using half of a horseshoe and carve a horse head for the handle. I quench these in SuperQuench and do not draw a temper.
I contacted St Croix Horseshoe Company and was told that they use A-36 for their horseshoes, as I believe most other companies do. Generally when you buy mild steel you get A-36.
I have checked the data sheets for A-36 and find that the minimum Carbon content for A-36 is 26 points but it may be higher. Most A-36 is made from recycled steel and may have varying amounts of Carbon (but no less than 26 points).
I do not have a pyrometer so when I quench I bring the blade up to non-magnetic. To determine this I bring the heated blade close to a suspended magnet and watch for movement of the magnet. I hope that the magnet is attracted to the blade. I then increase the heat in small increments until it is not attracted. At this point I quench it. In reading today I see that Robb suggests quenching at a “light cherry red”.
I don’t have access to a Rockwell tester so have been unable to determine what the Rockwell rating that is obtained. I do know that a good file skates on these blades. I carry one of these knives as my EDC. My wife carries a Case Equine knife and I have to sharpen her Case more often than I do my EDC. She primarily uses her knife to cut the twine on hay bales.
I would like to learn what hardness SuperQuench obtains on A-36, as I am sure that many others would. Perhaps someone who has a Rockwell tester will be willing to test this and give us their results. If anyone who would like to perform this test and either does not have access to A-36 or SuperQuench I will forge a blade from half of a horseshoe and send it to the tester or testers, if more than one person would like to test the blades. Matter of fact, when I get ready to quench the blades for these tests I will pay attention to the color and if it is different than the results obtained by quenching at the non-magnetic test I will send blades using each quench temperature. These will be forged and quenched but not ground and without the horse head carved for the handle. After the testers have reported their results, if they would like, I will forge a blade, harden it using the quench temp that got the best results, grind it and carve the horse head handle and send it to them. They are also welcome to finish the test blades and keep them, give them away or sell them. My touch mark will not be on the test blades but will be on the finished knives that I supply.
 
Wer make and sell a lot of spike knives since we are in coal/railroad country..The factory specs for "mc" spikes Ive seen are around 1020 steel with the "hc" spikes being around 1030 steel..With the 1030, superquench will make a hamon, this I know for sure..Ive been told(keep in mind this is second hand info) that a "hc" spike will get up to about 52 rc with super quench..
We keep a 5 gallon bucket of super quench on hand..
 
Thank you very much for the great information, Wayne. Just because "Everybody says you can't" doesn't mean you can't if you try a little harder. Denny
 
This a series of e-mails that I have exchanged with Robb yesterday and today. I will also add this info to my thread about SuperQuench.

Hi Wayne,
You're welcome to post or use the info any way you want.
Robb

Thanks for the quick reply and the information. I will post this on www.knifedogs.com with your permission. You might want to check out this forum. It is G rated, friendly and a good place to exchange information. I hope to see you again some time soon.

<);-)>
Wayne Coe
Artist Blacksmith
729 Peters Ford Road
Sunbright, Tennessee 37872
423-628-6444
www.WayneCoeBlacksmith.etsy.com
WayneCoe@highland.net

Subject: RE: SuperQuench


Hello Wayne,

The Super Quench is often used on A36 steel by many blacksmiths. When we were doing a series of tests at Sandia National Laboratories we consistantly achieved 42 to 45 Rockwell C scale on certified 1018 steel. Typically A36 has between 26 and 36 points of carbon. I would expect that you could get around 48 RC on A 36. You usually don't know exactly how much carbon you have in it, so there may be a little of variation in hardness. One other trick you might try, is to bake your finished knives is a toaster oven at 400 F for one hour. This greatly improves grain refinement after hardning even without a temper. If you are interested in a good book on heat treating that is easy to understand try: Selection, Application, and Heat Treatment of Tool Steels by William Bryson.
I hope this is helpful,
Robb Gunter


>
Subject: SuperQuench

I have met Robb (at Quad State) and Chad (when he was William Rogers assistant at John C. Campbell Folk school).
I have been making knives from half of a horse shoe and hardening them with SuperQuench. I have read articles on the internet and see that Robb states that he get a RC of 42 on 1018.
I have contacted manufacturers of horse shoes and have found that they use A-36. ANSI specifications state that A-36 must have a minimum carbon content of 26.

My question is, “Have you tested A-36 and what RC do you get on it?

On my knives I SuperQuench but do not draw any temper. They hold an edge well, as a matter of fact, my wife carries a Case Equine knife and I have to sharpen it more often than my EDC “Horse Head Horse Shoe” knife.

Thank you for your help here.

<);-)>
Wayne Coe
Artist Blacksmith
729 Peters Ford Road
Sunbright, Tennessee 37872
423-628-6444
www.WayneCoeBlacksmith.etsy.com
WayneCoe@highland.net
 
I make all of my tomahawk heads from A36 and SuperQuench them. I've never had a complaint about the quality of the edge.
 
I'm up late, but I just got a crazy thought... What about 4140 using the super quench as a knife steel? I thought I understood that 4140 wouldn't be good enough for even a chopper, but if it's extra hard, would it work for a knife?
 
Wayne, thanks for the bump on this. A really interesting bit of reading.

The Sodium Hydroxide quench sounds a bit scary for me though! We use it for unblocking drains and it eats through everything! I guess it's a quicker mix to make up.

I have a railroad spike waiting to be forged out. I was thinking of welding on a decent steel for the edge but may play around with this instead.
 
I used to mix powders in a chemical plant for a living, mostly making industrial-strength cleaners, and worked with sodium hydroxide (AKA "lye") on a weekly if not daily basis. We sold literally TONS of the stuff in solution, to dairies that needed to clean the fat and grease out of their pipes. (Think about that for a second :) ) It's highly corrosive and fairly reactive, especially when exposed to water, that's why it works so well as drain cleaner. I have the scars to prove it... a few grams getting under your boots onto your sweaty feet/ankles will ruin your whole week. The reaction takes a few seconds to get going, it will tingle, then irritate, then HOLY SMOKES THAT HURTS!!! at which point it's too late to do much except flush with LOTS of water or a mild acid solution like vinegar (works quicker, but has its own hazards) and try to stop the reaction from getting worse. It's not as wicked as sulfuric acid or, God forbid, nitric acid, but it can and will BITE you deep. Depending on the concentration, it can also corrode many steel and aluminum alloys right before your eyes. Breathing the fumes? NOT a good idea.

I suspect that Wayne's point is, there are other salts that are much safer and work nearly as well for quenching purposes.
 
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The comments about Lye are that it was to dangerous to use so SuperQuench was invented. Use SuperQuench not Lye for a super fast quench.
As far as other salts. Brine is quick, SuperQuench is a Brine but faster. All that I have any knowledge about is Brine (Ice Cream salt) and SuperQuench.

BTW James, I'm sorry to hear about your feet. Sure makes it more understandable.
 
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