The Swamp Rat Free Rein 28 . . . Coming Sunday, January 14, 2024, At 9:00 PM Eastern

[Cobalt]

this is from eknives, for a folding blade.

The process of stonewashing​

1. To get started creating your custom knife, you’ll need a knife, five to 10 small stones (about half a thumb’s size), a large plastic jar or container (like an empty mayonnaise jar), nail polish, nail polish remover, a towel, rubber bands, WD-40 or dish soap and a dryer.
2. Disassemble the knife and cover the places you do not want to be stonewashed, like the pivot, in nail polish.
3. Place the blade in the plastic jar along with the stones and spray some WD-40 or soap and water on top of the rocks.
4. Close up the plastic jar and wrap it in the towel. Use rubber bands to secure the towel around the jar so you don’t damage your dryer.
5. Put the towel-covered jar in the dryer in a heatless dry setting. This might be called tumble dry or air fluff. Leave it in for 10 to 20 minutes–depending on how dark you want the finish to be.
6. Remove the blade and clean it to remove residue. You can use nail polish remover to remove the nail polish. Assemble the knife and sharpen the blade to see the final outcome.

 

[MattinLA]

Awesome design. In for a coated one to match my Free Rein.

Which coating? I love Swamp comp, but for this my inner Ninja is telling me coated...for stealth purposes
I love Sage, but might try Desert Bronze and then, if needed, strip it for that awesome black undercoating.

 

[Busto]

I've heard the same. I think the blades undergo an acid etch before stonewash that builds up a layer that protects against further corrosion. But I don't really know if that is true or not.

What actually takes place is called: Pickling or Passivation....a process to remove "Iron" contaminants on the surface introduced during manufacturing, machining of the parts. What you see as rust spots are the Iron Oxides in or on the surface. This process was introduced to treat Stainless Steels that see Oxygen in highly flammable service situations.....Which is what happened on Apollo 3 that burned up on the launch pad killing 3 astronauts.

The Acid actually eats the Iron to remove it from the surface...depending on the size of the article it's a 15-20 minute soak in Nitric 25-45%/Water Bath.

 

[W.E.S.T]

Which coating? I love Swamp comp, but for this my inner Ninja is telling me coated...for stealth purposes
I love Sage, but might try Desert Bronze and then, if needed, strip it for that awesome black undercoating.

I just went with black coating. I had a TNT-15 with desert sage and it looked really good. I also want to try the desert bronze at some point. Stripping it doesn’t remove the black base coat?

 

[MattinLA]

I just went with black coating. I had a TNT-15 with desert sage and it looked really good. I also want to try the desert bronze at some point. Stripping it doesn’t remove the black base coat?

I haven't stripped the Desert Bronze, yet, Anton did and it left a tough black almost DLC undercoating.
I stripped a Sage BG Boss Jack, Citristrip, and it left a Earthy undercoating that is also tough. The Citristrip didn't affect the undercoating at all.
So unless they change the process... I'm in!

 

[Cobalt]

What actually takes place is called: Pickling or Passivation....a process to remove "Iron" contaminants on the surface introduced during manufacturing, machining of the parts. What you see as rust spots are the Iron Oxides in or on the surface. This process was introduced to treat Stainless Steels that see Oxygen in highly flammable service situations.....Which is what happened on Apollo 3 that burned up on the launch pad killing 3 astronauts.

The Acid actually eats the Iron to remove it from the surface...depending on the size of the article it's a 15-20 minute soak in Nitric 25-45%/Water Bath.

I wonder how nitric acid works compared to ferric chloride in 8% Cr steels.

 

[Busto]

I wonder how nitric acid works compared to ferric chloride in 8% Cr steels.

Well the difference is that Ferric Chloride is a "Corrosive Salt" and Nitric is a True Acid....The action is to Remove Machining SWARF tiny bits of iron left from "Tooling Bits" that flake off in machining...so if it's a Mirror Finish or INFI Satin that debris may already be gone from polishing.

You could Dilute the Nitric down to a level where it less corrosive which I suppose is possible with ferric chloride also and adjust time of soak. It's been my experience with reagent grade nitric it's definitely more aggressive than Ferric Chloride. I have etched pattern welded steel (damascus) with ferric, but not with nitric. I have passivated 154CM, CPM 154, S30V, S45V, Elmax, AEB-L, and they all reacted similarly with no real after effects like discoloration.

 

[Cobalt]

Well the difference is that Ferric Chloride is a "Corrosive Salt" and Nitric is a True Acid....The action is to Remove Machining SWARF tiny bits of iron left from "Tooling Bits" that flake off in machining...so if it's a Mirror Finish or INFI Satin that debris may already be gone from polishing.

You could Dilute the Nitric down to a level where it less corrosive which I suppose is possible with ferric chloride also and adjust time of soak. It's been my experience with reagent grade nitric it's definitely more aggressive than Ferric Chloride. I have etched pattern welded steel (damascus) with ferric, but not with nitric. I have passivated 154CM, CPM 154, S30V, S45V, Elmax, AEB-L, and they all reacted similarly with no real after effects like discoloration.

How much are you diluting the nitric acid?

 

[The Knife Life]

The action is to Remove Machining SWARF tiny bits of iron left from "Tooling Bits" that flake off in machining

The iron being removed isn't from the "tooling bits", it's native in the steel itself (of the blade).

Passivation reacts with this surface level of iron and removes it leaving behind a passive surface of Chromium oxides which resist corrosion much better than free iron, hence the reason it's done.

If the surface of the steel becomes damaged, you will have to passivate again to deal with the iron now exposed in the damaged area.

Most modern tooling bits used these days to mill the steel are sintered carbide, not steel, which have extreme wear resistance and really won't be leaving any iron in the object being machined anyways. Even if it was HSS like a common drill bit, the amount of iron it may leave on a knife is negligible and only on the surface if it were to break off (unless you crash the machine and really bury that sucker in your work piece, then it can really be embedded in there! Lol). The amount exposed in the freshly machined knife blade is a part of the blade steel itself and is far greater than anything coming out of the machining cutters.

 

[tinfoil hat timmy]

well that's neat

 

[Busto]

How much are you diluting the nitric acid?

Usually I start with 25%...but I can dilute that if necessary. Since I have test coupons I try this dilution and adjust from there....Remember always add acid to water not the other way around. The Nitric I use is 70% reagent grade by weight...which is common for reagent grade nitric.

 

[Busto]

The iron being removed isn't from the "tooling bits", it's native in the steel itself (of the blade).

Passivation reacts with this surface level of iron and removes it leaving behind a passive surface of Chromium oxides which resist corrosion much better than free iron, hence the reason it's done.

If the surface of the steel becomes damaged, you will have to passivate again to deal with the iron now exposed in the damaged area.

Most modern tooling bits used these days to mill the steel are sintered carbide, not steel, which have extreme wear resistance and really won't be leaving any iron in the object being machined anyways. Even if it was HSS like a common drill bit, the amount of iron it may leave on a knife is negligible and only on the surface if it were to break off (unless you crash the machine and really bury that sucker in your work piece, then it can really be embedded in there! Lol). The amount exposed in the freshly machined knife blade is a part of the blade steel itself and is far greater than anything coming out of the machining cutters.

Tooling bits do leave behind particles...As a Journeyman Machinist and Engineer who has worked extensively with metals, especially stainless steels in the Aerospace industry I can assure you teeny tiny fragments are embedded in the machined metals. The onsite metallurgy lab did the testing of machined metals to conclusively confirm they were there. Our Machine shop turned out Thousands of "AN" fittings and Very Specific Aerospace Hardware that flew on the Orbiters (Space Shuttles) So I have a good idea of what the Tooling deposited on Inconel, Monel, 304, 303, 17-4....as well as some other less common hardware.

 

[dogboye]

That would make sense as I’ve also heard that bead blasted blades tend to be more prone to corrosion or freckling.

I've never had a problem with bead blasted INFI. I've got several, one that has been used quite a bit on wood, green wood, trimming fallen trees... and another that I've use to cut mean, veggies, etc. I don't exactly leave them laying around wet, but they'll end up having whatever on them for a few hours until I can clean them properly.

In fact, the only INFI blades I HAVE had a problem with are competition finish, and stripped coated ones (that I have trouble getting the decarb layer off sometimes). The decarb layer will rust while I watch, practically.

 

[Cobalt]

Usually I start with 25%...but I can dilute that if necessary. Since I have test coupons I try this dilution and adjust from there....Remember always add acid to water not the other way around. The Nitric I use is 70% reagent grade by weight...which is common for reagent grade nitric.

Walmart sells the 70% nitric. I am going to try it on one of my SHBM's. Or maybe the Rat Daddy LE

 

[DamascusBowie]

The desert bronze looks like raw gold to me, I love it.

 

[780ninja]

I’ve been asking for a Res-c two hand sword for years now and ITS HERE ..
I’ll take one til the 23-24” Free Rein blade comes

Hoping this Extra bacon gets put on OMG-28…Need a two hand gladius

 

[Cobalt]

I want one, but I am figuring I will never use it. Hard to justify for me. I still want one.

 

[adluginb]

I want one, but I am figuring I will never use it. Hard to justify for me. I still want one.

The same thing I went through 15 years ago when I bought my first sword. That sword has been in my closet for 15 years and has never seen the sun light.

But you know what? I wanted the damn thing so I got it. May even go touch it before I go to bed.

 

[Cobalt]

The same thing I went through 15 years ago when I bought my first sword. That sword has been in my closet for 15 years and has never seen the sun light.

But you know what? I wanted the damn thing so I got it. May even go touch it before I go to bed.

I am going to order one, and there is a cottonwood that needs to come down. So I may use it for that. I took a huge chunk of it this last year, but it is big and its roots are killing my other trees. So it has to go. This may be the springtime tool for it.

 

[MattinLA]

I am going to order one, and there is a cottonwood that needs to come down. So I may use it for that. I took a huge chunk of it this last year, but it is big and its roots are killing my other trees. So it has to go. This may be the springtime tool for it.

My Rodent Rucki has spent many years as a champion palm tree frond killer. The Rucki has earned it's keep through Many Tactical Gardening deployments.
The FR28 will usher in a New Age of Backyard Shenanigans