How to heat treat rebar knives for edge retention...it works!

Will a rebar knife harden if quenched and tempered properly? And if so, how well will it hold an edge? The subject of heat-treating is controversial when it comes to rebar and a lot of other "mystery" steel. People have been arguing about the qualities of rebar probably about as long as it's been around. Here I prove that you can indeed harden a knife made of rebar, at least some types of rebar, but will the knife really stand up to abuse? And what kind of edge retention can you expect?
If you liked this video please check out some of my others:
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Also, check out GeographyCzars great channel. He mostly tests and researches the performance of small caliber defensive weapons using Ballistic Gelatin:
/ geographyczar

[@OUTDOORS55]

Id like to know the hardness of the treated knife. I was really impress how that held up. Id be interesting to see how well it held a razor edge. Ive found you can tell a lot about how good a steel is by putting a very sharp edge on it, and see how well it holds that edge cutting cardboard. Cheap steel, and steel that isn't hardened properly loose their razor edge VERY fast. Theres something about that very fine edge, that shows a steels strength or weaknesses. Great video!

[@FargoFX]

OUTDOORS55 Thanks for the comment. Very informative, I'll keep that in mind on future tests.

[@tracymitchell9399]

I'm a little late to the party on this video considering it's been 3 years but I do appreciate you doing it. Thank you.

[@waynelewis881]

Well done. I guess most everyone had a pretty good idea what the outcome was going to be, but actually seeing it is always best. I’d really like to see that same comparison between a rebar edge and a railroad spike edge.

[@billgator2005]

i think the question of whether it can be hardened is determined by what GRADE rebar you use. all rebar is not created equal. there are several different grades. carbon content is the critical factor.

[@randomschittz9461]

Is there a good way to tell the difference?

[@sammy13ificationable]

What's learned from this. You can treat anything, if you do it right

[@mountainholler290]

I've found that with rebar some are much better than others , bottom line is test and try different quenching mediums .

[@robinhoods-homestead]

Rebar makes amazing tools

[@jakemakes]

I agree that you need to test each individual piece of rebar. Every piece has different carbon content. Heck, a guy on bladeforums told me he found a piece with a solid vein of copper running through the whole thing!

[@FargoFX]

Jake Makes Lol, I'm hoping to find one with a solid vein of gold.

[@huckstirred7112]

the serious high grade re-bar , like the huge stuff used in high rises ,has I believe 40 -45 percent carbon and it is really tight specks .I have 3 ft of it in my shed . It does have numbers and letters as in a code but I'm not going out there right now. LOL

[@craigcook1571]

@ JM I use to cut and fabricate rebar back when the Dinasors walked,(1970's), and it was amazing the difference in hardness from stick to stick. Some of it cut like butter, and every once in awhile you would cut one so hard it would almost explode into pieces and usually chipped the blades on the cutter

[@dayostrvladimere6349]

This is great thank you this shows that anything in a situation can do not perfect but if you came across a rebar somewhere and needed it could make a shape steel piece that will do things basic great work

[@dicedoomkid]

I appreciate your assistance friend.

[@halfpotatohalfunicorn9009]

Wow im impressed and you sad it took you like a few hours to build one so thats very good.

[@TshirtWetter]

Awesome video! Great work... I made an axe out of rebar but wanted to get more information regarding heat treatment and annealing before finished the edge! Thanks.

[@TheCryptoman]

Great video that was a awesome test. Thanks for sharing.

[@FargoFX]

TheCryptomanHiking&Bushcraft , thanks my friend, glad you enjoyed it! Cheers!

[@ulteriorresources]

Very helpful information

[@clauscraut]

Thank you! Interesting video!!

[@manzurulgalib4651]

Man you are awesome. I love your explaination

[@nebianninja8846]

Really good video

[@tomb2623]

about 2 decades ago, I attempted to harden 15 pieces of rebar steel to as hard as they go. Resulting in pretty much all of them cracking, specifically when cooled in water. When cooled with oil, i think some of the samples survived, some of them being up to 60 hrc :)

[@Divine_Serpent_Geh]

Tom B You never know what you get with rebar, but I’ve heard the old stuff is much better. 60hrc is pretty damn high with oil. Probably 62 with water

[@colsoncustoms8994]

With lower carbon steels, I find that only doing a snap temper gives the best results. I do a peanut oil quench from a fairly bright orange, say around 1,600-1,800 degrees depending on the type of knife (mainly size, smaller ones get quenched a little cooler so they don’t get burned up in the forge). I like to get the blade up hot enough while forging that I see some “bubbles” start to form on the surface. Those ones always seem to be harder after normalization and quench than the ones that were only taken up to a medium bright orange. I make sure it fully cools in the oil below about 200 degrees so that handle doesn’t draw back the temper as the heat migrates back down the blade (or just not get hard if it was left at say 450 degrees where it seems to auto temper at whatever temp it’s left at). Then temper at around 300-350 for an hr just to relieve any stresses. On the higher alloy stuff I use (wrenches for wrench knives of a specific brand) with only about .3-.35% carbon, I can get a pretty nice edge from this process. I’m grinding them down to about .040”-.060” at the edge and only grind off the forge scale from the edge itself after heat treating, not taking off 1/8”. Since they are so thin and I’m using a charcoal forge, I’m fairly certain there’s a little natural carburization taking place and although it goes well past the edge, the core of the blade likely has a slightly lower hardness. That’s dependent on thickness though. Some of the really thin ones that get really hot during forging seem to get surprisingly hard. I’ve tried the same recipe on thick railroad spike knives and had mediocre results in comparison. Likely the main culprit is the lack of alloys, then how the thicker stock cools slower during quench, and potentially less carbon migration, although I’d assume that would be more a factor of temp + time + available carbon, not so much the thickness.

[@JustinTopp]

I found a bunch of hydraulic oil well pipe that acts like 1095 and hardens the same too. Not the same steel but similar. Some kind of high carbon very tough too. Good stuff. I’ve got 50’+ of it. Annoying to straighten but worth it.

[@DarrenMalin]

Interesting thank you.

[@kimcurtis9366]

You can always use an old belt for a strop! Put some compound on it and strop away! They work pretty well and far better than your welding gloves! Cheap, too! Good video! Make throwing knives to practice with!

[@zincoleo1]

yeah, there's a 90yo barber where i live, when he was a boy he shaved my grandgrandpa, when he was a teenager, my granpa, and so on, and he always used a buffalo hide belt to strop his razors, and they got sick sharp

[@stauffap]

Cardboard works as a strop as well. "Cutler cutlery" promoted this as a cheap stropping method and it really works. Apparently there are fine clay particles in cardboard that have a similar effect like a polishing compound. I'm able to get a shaving sharp edge this way.

[@craigcook1571]

Another good cheap source for a belt to make into a strop is goodwill

[@humbertohuizar1375]

What grade rebar did you use? Try using a 100grade piece if it’s available in your area would like to see your test with that👍🏼

[@BurntKittyForge-pl8ol]

edit: i was really wondering for say seven foot span how much more rigid the rebar rod becomes in terms of posts ...so maybe a spring steel hardened rebar slid into pex pipe (maybe snug or has grease for rust free ) , both affordable , anyway if a shed is made from that as the frame and foamboard insulation used i wonder , but i daydream about rebar and cement inside pvc for posts etc, i've decided to stick with cinderblock full of concrete, 10 foot rebar into concrete footer for shed , porch with gutter support independant from house, carport shed posts design

[@gravelman5789]

👏👏👏🖒 have u researched Case Hardening? im thinking once u have a Blank made u can Soak it in a Reducing atmosphere, (i use a piece of Tire) then Heat Treat like normal...😉

[@xgu4642]

I’m wondering because this could be very difficult to try but would layering it harden it better.

[@KageShi]

I know I'm late but I had an idea about this to make my own camp chief knife, Have you tried forge welding a higher carbon steel wedge into one side of the rebar to take the edge? Physical issues are slowing me down in my progress however am trying to make a 4in chief knife to clean and process small and medium game.

[@REAPERMILITIAOUTDOORS]

Awesome

[@FargoFX]

REAPER MILITIA SIDETRACKED Thanks, my friend 👍

[@Coleman77]

Case hardening with “cherry red” ? Much appreciated!

[@mindofmadness5593]

Maybe you should make some conversational table kniives-bet they cut steak fine. Even something Old Hickry style.

[@amaanshaik9758]

Conventional?

[@mindofmadness5593]

@@amaanshaik9758 well sure that too bu if you are havin guests and you place a rebar knife on the table it's going to start a conversation too. :D

[@amaanshaik9758]

@@mindofmadness5593 true

[@cdrom1070]

i noticed the softer wood sharpened way better and cut paper better for the same amount of effort. The hardened one tore a bit.

[@johnnyhughes9178]

what grade of rebar did you start with 60 or 40 60 vrade is

[@ToxicFruit]

So how much time passed between the initial annealing/quenching and the heat treatment?

[@leemday5731]

Good news! I read last year in some industrial paper international standards have ordered that more carbon and a little moly and vanadium be added to rebar becous to much infrastructure not earthquake proof and failing so rebar makers need to make changes the spec is not far off en45 or truck spring steel..at last!

[@djordjepavlovic5870]

same woukd happen if you made a knife out of propper inife steel. it would also go dull when hamered on rebar

[@craigcook1571]

Both, especially the hardened one would work in a pinch

[@droppoint495]

Good show i would like to have seen if one would scratch the other

[@reconwatcher9475]

Well Done !!!!! Many Thanxxxx !

[@andycraig6905]

Case hardening?

[@caomunistadoggo4129]

But if you don't do the temper after heat treating?

[@matthewsherriff-growingfoo3110]

Would rebar be good steel to use for forging hammers?

[@billgator2005]

the better test is strike the blades together. the one with the least damage is the harder

[@wwoodworks1021]

Do you know anything about railroad spikes? I have some of the smaller ones I'm able to forge.

[@FargoFX]

Saline Woodworks No, i'd love to get some spikes and do some different projects with them, and edge testing would be a good one.

[@wwoodworks1021]

I could send some of you want! I have like 25

[@FargoFX]

Saline Woodworks I appreciate it. But there's a local place I can get them, just been too lazy so far. LOL. Thanks again! Hey, checked out your channel…good work, new sub. Odd though, I watched one of your videos before and I thought I subscribed, I guess not. Anyway I definitely did now. Cheers!

[@wwoodworks1021]

Thank you!

[@huckstirred7112]

rail road spikes with HC on the head has 40 percent carbon . Not enough for even a half decent knife .will it work yes not very well but will work .not worth the effort .

[@oldgoat8132]

Have you tried quenching it in brine (water saturated with salt).

[@randomschittz9461]

That sounds interesting. What does that do?

[@oldgoat8132]

@@randomschittz9461 as far as I understood the salt makes the heat transfer a lot faster, making the Steel Even harder.

[@Spike-qn3qn]

any suggestion how to temper a knife without an oven???? coz i dont have

[@drevil8223]

How don’t you have an oven

[@Spike-qn3qn]

@@drevil8223 because we have different way of living..... Maybe youa are rich and i am not thats it

[@Simo_-rv5dw]

You can try use your forge/fire and put the knife near it, but is very hard mantein a constant temperature...

[@brianwiggins2169]

King Lher Meniano you don’t have a regular cooking oven

[@binauralboost7401]

If you can get your hands on a toaster oven, one of those small counter top ones might work.

[@AlexEllis]

I thought rebar was made of mild steel rather than high carbon?

[@ianfinrir8724]

Depends on the rebar.

[@sirdanielsmalley9657]

The second paper test made me sad.

[@braindeadnewyorker9569]

First comment 👍

[@FargoFX]

brain dead New Yorker First comment on the first comment! 👍

[@Mwhbmnabjms]

Shold have test oil vs water quenche-

[@garysumlin8355]

Regular rebar does not work like you get from Lowe's or Home Depot

[@thecoolguy1233]

3:19 you can hear someone call "Dad!" lol

[@HB-jc9uf]

Your didn't anneal but tempered

[@Nas96__]

0 dislikes...

[@antonstorchak4388]

Thanks for the tests! What if you try to hit the heat treated edge over the soft one and see how far one edge harmed another one? And one more question, have you ever try to do a blade carburizing, you know to get more carbon into the blade? kzbin.info/www/bejne/nJDFiZx_m8h1jdU

[@effyou128]

its Mild steel its never going to hold a edge

[@HB-jc9uf]

Depends on rebar some 1045 sometimes w1 some 1095 so it's a stupid video