1080? 1084? 1095? Your Preferences Please, Gentlemen.

[Slash McCoy]

My new Paragon thermostatically controlled electric heat treat oven is coming next week. No more barbecue grill razors. I know that forge heat treated razors are best made with 1080 or 1084, but if I follow the standard protocols with 1095 is it pretty foolproof? And are there any advantages to 1095 or O1? Thanks. BTW I have O1 and 1095 on hand.

 

[P.G. Gibson]

The big thing I would keep in eye on with 1095 is taking steps to control decarb and use a proper quenchant. If your pre heat treat grind is like 20 thou you’re going to find it for sure. I don’t think I’d consider 1095 “foolproof”. Also accepted protocols on 1095 is kind of open ended because there are a lot of them. Everyone kind of has their own take, even more than you see with other common steels.

I’ve done several batches of trade knives from 1095 that starts as 93 thou stock and even taking very careful steps in my kiln, I get decarb that runs deeper than I would have expected. Both O1 and 1095 will make good razors (one of my best shavers is a BB in 1095).

If it were me and I was still getting my processes dialed in on a new kiln, I’d go with the O1. I think you’ll getter better results sooner.

 

[Slash McCoy]

Cool. Thanks for weighing in. In the meantime I already ordered some 1084 so I now will have 1084, 1095, and not sure but I think I have some O1 too. I decided to get a 5gal bucket of Parks 50 and I might get the McMaster Carr 11 second oil too. I was using canola or peanut but I had a couple barbecue razors come out sort of meh on the hardness and I am more suspicious of the oil than anything else. Tried brine and had a couple crack on me but the survivors were nice and hard, and honed nicely after medium//light straw. Just using magnet and eyeball for HT temp but I think I was consistent enough. Tried different quench heats and 160 by candy thermometer seemed to be best so I will guess that the oil was just a bit too thick for best O1 results. I haven't completed any 1095 razors yet. All grinding is temporarily on hold until I get my DIY twinned grinders set up.

And since it is already on the way, what do you think of 1084? I really want to be making way better than average razors before the end of the year and I don't mind having to work at it. If the first few attempts are not so great, no biggie. The world needs more amazon box openers. I am looking for hardness results of HRC60 and no microchipping, good edge retention at a 16 degree bevel angle. I don't care if they take a long time to hone. So if they come out harder than 60 but don't microchip then that's okay, too. I am looking at picking up a dewar and trying some nitrogen cryo treatment, to that end.

 

[bluesman 7]

I can't imagine any oil being too slow for O1. That stuff seems to want to get hard. I've never actually worked with 1084, but it is known for being the easiest steel for heat treating. Near uetectoid with fairly high manganese, so a bit deeper hardening than 1095. I've been using 1095 exclusively for the past four years.

 

[P.G. Gibson]

Bluesman are you using Aldo’s?

 

[bluesman 7]

Bluesman are you using Aldo’s?

Yes I am.

 

[P.G. Gibson]

Yes I am.

Good stuff.
In case slash goes the 1095 route: what do you do during your norm cycles to mitigate decarb (if you don't mind me asking)? Or am I alone in that observation? I have used satanite and SS wrap during normalization, but I think most of the decarb is coming in during my quench heat. Part of the problem could be that most of my work with 1095 has been in thinner cross section stock.

For me, I notice it mainly when there is a finished face that was very close to the original stock face (like just a "cleaned up" surface) I plan around it for the edge by leaving extra material.

Slash, I can't tell you how excited I am to see you going whole hog into razor making by adding a kiln. I can never adequately thank you (and I'm sure I'm not alone in this) for the contributions you have made to my honing regimens. I have zero doubt that the razors you make will be exceptional, and I hope one day to own one.

For the record I think 1084 is absolutely capable of making an above average razor. You can hit 60HRC easily. Look into Cashen's 1084 regimen (I think it is here on BB somewhere, but I can't find it at the moment). It is an excellent place to start.

Couple of tips for getting your new heat treating setup in place:

1) Get a few K type thermocouples from Amazon and a dedicated digital reader for them. You can find these on Amazon for less than $30. They make some with long stainless steel probe bodies that are perfect for dipping into your quenchant. Nice big digital readout too! I have tested dozens of these (the probes) and even the cheapest are within a few degrees of true.

2) Let your kiln soak when you first fire it up. Give it at least 15 minutes once it hits your target temp before you open it again. The thermal mass in the refractory walls helps balance things out. This will allow it to recover faster after you've put a blade in and also help avoid overshoots (which on thin stuff really can make a difference). Judging soak times can get tricky when it takes 10 minutes for your kiln to recover from an opened door.

3) For tempering, you may find the Paragon a bit tricky. It can be done, but a normal oven (like in your kitchen) is actually a lot easier to dial in and they are remarkably stable once you get some experimentation and data in on them. On kilns, when the elements fire they can hammer things with intense IR and you can overshoot fairly easily unless you really have things dialed in. If you are going to use the paragon, you might want to build some temporary baffles in between your coils and work piece (like a sheet of SS or SS foil) to help intercept some of that.

4) For tempering in an oven: I really like the iGrill from Weber in my oven. It is intended for smoking and BBQ applications but it connect via bluetooth to an apple or android device which allows you to get a visual graph of whats going on on your tempering tray. I hang my probe about an inch away from my work piece on the same tray. Doing this helped me see that my oven was accurate to within a few degrees and in a very predictable way. I now have a graph of the temper cycle for everything I make! This also helped me see that the oven doesn't become completely stable until about 30 minutes after it has hit target. Again, this helped avoid overshoots.

Sorry for the long post! Hopefully some of that is helpful. Can't wait to see your results!

 

[bluesman 7]

Good stuff.
In case slash goes the 1095 route: what do you do during your norm cycles to mitigate decarb (if you don't mind me asking)? Or am I alone in that observation? I have used satanite and SS wrap during normalization, but I think most of the decarb is coming in during my quench heat. Part of the problem could be that most of my work with 1095 has been in thinner cross section stock.

I do my HT in a CO atmosphere in a muffle in my forge. I temp cycle with a flash quench in oil to minimize de carb in the cooling cycle. I'm not going to martensite with these quenches cycles, just under 1000 F. At these temps the pearlite forms quickly. I create the CO atmosphere by putting a charcoal 'getter' in the muffle. NOTE; this charcoal 'getter' can not be used in a HT oven as CO is a fuel and could easily cause an explosion! I sand to 320 before my heat treat and see very little scale or surface deterioration from my heat treating.

 

[P.G. Gibson]

Very cool - thanks for the info! If Im fighting scale in the forge I usually just run a rich mix which helps a lot, but I’ve never thought of putting a carbon source inside the muffle before. Smart!

 

[bluesman 7]

The first time that I tried it I thought that I would be burning through charcoal like crazy. I learned that the charcoal is very nearly not consumed at all due to there being so little oxygen available. A small piece lasts though several razors and after the forge cools down the charcoal is mostly still there.

 

[bluesman 7]

3) For tempering, you may find the Paragon a bit tricky. It can be done, but a normal oven (like in your kitchen) is actually a lot easier to dial in and they are remarkably stable once you get some experimentation and data in on them. On kilns, when the elements fire they can hammer things with intense IR and you can overshoot fairly easily unless you really have things dialed in. If you are going to use the paragon, you might want to build some temporary baffles in between your coils and work piece (like a sheet of SS or SS foil) to help intercept some of that.

I use a chunk of 4"x 4" x 1/4" square steel tubing in my kitchen oven for tempering. Both to even out the temp swings and to shield the razors from radiant gain when the elements are on.

 

[P.G. Gibson]

Yep - I place a pizza stone in mine to add some mass. I also use the convection feature which helped even things out a bunch as well. The nice thing about having the probe in there right next to the blade is that it is small less massive than the blade itself. So any spikes that might hit register on it well before the work piece suffers. I usually see less than a 5 degree swing when the elements pulse. I have a table I've kept for what I set the oven dial to vs. what the work will actually see.

 

[Slash McCoy]

Thanks for all the tips, everyone, and thanks for the kind words, PG. I am glad to have helped and hope to continue to help more guys looking for a way or a better way or cheaper or easier way to hone. I have received a lot of help over the years from this community and it feels good to share back.

On a side note, UPS just delivered my new kiln a half hour ago. Got tongs yesterday. Waiting on my 5 gallon bucket of Parks 50. Still haven't built my twin grinder yet but there are a couple of O1 blades I started some time ago and maybe I can knock one out in the next few days and do my first "real" HT very soon. Busy with the new boat, totally wiring shore power, AC, and DC from scratch. It is starting to get hot in the 90s I guess, and the fridge on the boat is full of ice cold Dixie so things are going slowly. It is a lot easier to sit in the nice shady cockpit out in the breeze drinking brainfreeze cold beer than to sweat and bleed installing big heavy isolation transformers and shore power receptacles and breaker panels. Anyway I am really excited about the new oven. Tomorrow I will weld up a nice stand for it over in the hotwork corner of the shop. On another note, I might take another stab at 3D print scales and 7 day set cases with the new 500x500x500 printer. So many toys, so little play time LOL!

I was happy to see that the oven is already wired complete with 15a 120v plug so all I have to do is plug it in, and grateful that it shipped well and there are no cracks in the liner. I am gonna read the book tonight and mess around with it tomorrow. Pics below.

 

[P.G. Gibson]

Nice!! That looks like it is the perfect size for razors

Can’t wait to hear how the first heat goes!

 

[Slash McCoy]

Nice!! That looks like it is the perfect size for razors

Can’t wait to hear how the first heat goes!

Getting closer! Got my Parks 50 the other day, and my SS tool wrap foil a half hour ago. Got tongs. Oh, need bucket and lid for quenching but I get that at Home Depot. Still haven't turned the oven on. Dont have any razors ready for firing at the moment. I found two nearly ready, and one just cut out of bar, all three are O1. Delivery of my 1084 is eagerly anticipated around the end of next week.

Darn. I guess I need to weld up a couple of holders to hold the razors vertical, and a baffle chamber. This ove doesn't have exposed coils, though, so maybe a baffle isn't so important, but I definitely don't want the razors laying down on their sides. I ordered a couple of ceramic racks today but they will be a while getting here.

I might grind out a kitchen cleaver or chopper or something for the first heat. Only a couple hours of work in that. I would hate to have a hollowground razor crack on me after a couple days careful grinding. It has happened to me already and it is a real downer.

 

[P.G. Gibson]

That’s great! Yeah you will be fine without baffle for the normalizing and hardening stages. I primarily was recommending a baffle if you were going to try to run your temper cycles in there, but with those shielded coils you’re right: you probably won’t need it.

Obviously, you won’t be using foil on the cycle when you quench. For that cycle just make sure your kiln body has a good soak on it and it will recover quickly.

You can make a temporary rack out of some scrap stainless and it will work fine. The ceramic ones just last longer after repeated cycles. I use a slice of soft fire brick with twisted kanthal for mine and that has lasted ages. You can also carve some out of small pieces of soft fire brick.

 

[Mr.Crowley]

Way to go Slash....can't wait to see this unfold

 

[Slash McCoy]

Soon. Soon. Gonna build a twin grinder first. It will make hollowgrounds a lot faster and more precise and consistent.

 

[147_Grain]

I wonder how well A2 would work for this sort of thing. There are certainly some advantages - relatively simple heat treat, air quench, high achievable hardness without sacrificing much toughness, among the least prone to warping from heat treatment of the common tool steels, etc.

 

[Slash McCoy]

I wonder how well A2 would work for this sort of thing. There are certainly some advantages - relatively simple heat treat, air quench, high achievable hardness without sacrificing much toughness, among the least prone to warping from heat treatment of the common tool steels, etc.

Advantages, yeah. Maybe the bad sock is on the other foot. Maybe there is some other reason why it isn't used for razors, I don't know. I will leave that experiment for others.