All this Talk of Comp Finish Rustin.

Once you can get that blackish grey outer layer off it's more stainless than ats34. This is already completely removed on factory double cut and satin blades, and having removed most of it myself It's no wonder why they charge more for those options. It seems they leave it on the comp/coated blades since there's no need to worry about it with a coating, and no one is supposed to care with a comp finished blade anyways :)
 
ZcouT said:
well sure, but as i understand it from this thread it started to rust during the time he was using it.

that is a little well extreme comparing to other steels that only might stain if you leave them i a wet sheath over the night.
Click to expand...

I agree, it does seem extreme. It probobally took a little longer than we think??? But as I said, the INFI dimples(and what Yoda said) are the culprit...as Ban explained.

Have you ever or seen one left wet in sheath with Dimples and unfinished raw that did not rust? I don't know of any other steel with dimples when raw... also a non stainless raw blade would rust around here if left in wet sheath overnight..I've had it happen with one my brother made that he had left the flats unpolished and raw on, and a couple of other carbon blades over the years(and those two where polished)

The polishing or DC on noncoated is what keeps all steels from rusting as fast.

I would say polished INFI would be about the same as polished D2 or stainless ATS-34 in rust resistance...maybe better than both of those.
 
Think of your skin as being the same as metal. When you take a hot bath your pores are open and allow breathing through the skin easily, when you go in cold water the pores close.

Similarly, after hot rolling and heat treat the steel has what you could call large open pockets or pores, which can hide moisture and cause the surface rusting you will see.

When you polish a blade, you reduce the depth of these pores and thus reduce the ability of moisture to stay within, thus it is much more resistant to rusting.

But how does DC do this when you are in effect creating dents for moisture to hide in. The reason being that they use ceramic media which imparts a ceramic coating from the beads that impact the surface of the steel. This has been discussed in the past on other forums and it makes 100% sense.

If you take a comp finish down to 400 grit you will significantly increase it's corrosion resistance. Hitting it with 320 grit ceramic beads will do the same.

One other note is that if you take the surface rust on the knife, it will come right off with a brillo pad or sos pad. You will notice that the rust does not cause pitting like it does in other steels. Pitting is a stress riser that can eventually lead to failure.

and herein lies the reason why you never hard chrome the surface of a carbon steel that is beng used for abrassive work like a knife. Hard chrome is not a vapor barrier and thus will allow moisture to wick through it's pores into the steel below. If the steel below is a carbon steel and not stanless, it will rust and this rusting will go unnoticed until the steel has severe pitting and the hard chrome begins to flake. When this happens it is almost to late. I am sure most of you have seen this in old bumpers and wondered why they rust, that is why.
 
ZcouT said:
well sure, but as i understand it from this thread it started to rust during the time he was using it. that is a little well extreme comparing to other steels that only might stain if you leave them i a wet sheath over the night.
Click to expand...

In this case it is only rusting because the dimples are rust magnets. INFI without dimples is highly rust resistant. If given the same surface finish.... INFI will be more corrosion resistant that a lot of stainless steel out there.
 
Any rust I've ever had has wiped off....but I DID get some decent patina on a SHBM from a combination of never cleaning it....coconuts....and trying to even it out with some vinegar. It looks cool. No rust though. I like the look of a used knife.
 
Ken44 said:
I agree, it does seem extreme. It probobally took a little longer than we think??? But as I said, the INFI dimples(and what Yoda said) are the culprit...as Ban explained.

Have you ever or seen one left wet in sheath with Dimples and unfinished raw that did not rust? I don't know of any other steel with dimples when raw... also a non stainless raw blade would rust around here if left in wet sheath overnight..I've had it happen with one my brother made that he had left the flats unpolished and raw on, and a couple of other carbon blades over the years(and those two where polished)

The polishing or DC on noncoated is what keeps all steels from rusting as fast.

I would say polished INFI would be about the same as polished D2 or stainless ATS-34 in rust resistance...maybe better than both of those.
Click to expand...

i totally agree, Ken. all my polished or Dc stuff is as rust resistant as my A-2 Blades, i love the rusting if not we could not have this great thread......thanks guys
 
Horton_Knives said:
i totally agree, Ken. all my polished or Dc stuff is as rust resistant as my A-2 Blades, i love the rusting if not we could not have this great thread......thanks guys
Click to expand...

The comp blades still have a layer of de-carb on them from the heat treat process. . . .That's the black or darker colored steel that you see above the edge. . . De-carb is very prone to rusting on pretty much any steel. . . If you remove it by either grinding or double cutting, then you have the real INFI steel surface and not the modified surface of the de-carb.

INFI has similar rust resistance to ATS-34 and D-2 due to the carbon to chromium ratio. . .

Make sense? If not. . . then you need to drink more!!!!!

Jerry :D


.
 
yoda4561 said:
It's a layer of decarb that wasn't fully removed after HT I think. Been working bit by bit getting my CGFBM refinished and it's easy to tell the difference between the "real" infi and the layer of decarb. The layer is really really thin, but incredibly difficult to remove. I really wish I had a sandblaster to do the work for me, since a scotchbrite wheel in a drill is really slow going, and doesn't get into the corrugations.
Click to expand...

Wish I had seen this BEFORE I made my last post. . . :eek:

You hit it right on the head. . . :thumbup:

Nice job!!! :thumbup:

Jerry :D




.
 
So after a few rust/clean...rust/clean cycles it will be more and more rust resistant?

:confused:

After it eats the decarb layer?


.
 
My comp squatches rusted, pretty bad. A little 2,000 grit sandpaper and some neverdull did the trick, then I pammed the blade. Hasnt rusted since. Im glade the sheath I had made for my squatch has a pocket big enough to hold a piece of a scotchbrite pad and some neverdull, so I can control rust if on an extended trip. The used neverdull also makes for some really good tinder.:cool:
 
GregS said:
My comp squatches rusted, pretty bad. A little 2,000 grit sandpaper and some neverdull did the trick, then I pammed the blade. Hasnt rusted since. Im glade the sheath I had made for my squatch has a pocket big enough to hold a piece of a scotchbrite pad and some neverdull, so I can control rust if on an extended trip. The used neverdull also makes for some really good tinder.:cool:
Click to expand...

Pam is the shit. It's multipurpose :D I use it to spray down the inside of my wetsuit so I can slide in and out real easy :p it creates a nice seal too :eek:
 
pbubsy said:
Pam is the shit. It's multipurpose :D I use it to spray down the inside of my wetsuit so I can slide in and out real easy :p it creates a nice seal too :eek:
Click to expand...

Thanks for that image, I just pictured the girl in your avatar wriggling into a wet suit, covered in Pam.:p
 
Funny, I just saw a girl that was just as hot doing exactly the same at wind and sea yesterday :D. I probably don't say this enough: I LOVE SAN DIEGO.
 
Heavy said:
So after a few rust/clean...rust/clean cycles it will be more and more rust resistant?

:confused:

After it eats the decarb layer?


.
Click to expand...

That was my thinking, so I never oiled it and even tried getting it to rust faster via soaking with saltwater/wheel cleaner (acid of some sort). Even with all that I've managed to wear out a 3 inch scotchbrite wheel and I still don't have it all off. The nice thing is that the decarb seems to hold oil pretty well, you can pretend it's really tough parkerizing :p
 
Sorry to revive this old thread, but...

If I understand correctly, the comp blades are cheaper because they come out of heat -treat and are decarbed with some solvent, and dried, then sent out.
So the final treatment would be removal of the decarb with what? Scotchbrite? (Or I guess Jerry uses a beadblast?)
Then the blades are finished as they are normally sent out, ie: coated or polished, etc.

So, my question is, what is the best way to remove the decarb? On a grinder with a scotchbrite wheel, send it for bead-blasting, or is there something else? Any chemical treatments? It seems like Ban was saying to polish, then let it rust, and polish again?
 
blast and stainless steel wool then scotch brite........ but, i like mine rusty....... if any one wants theres rust free, send it to me and i will do it at work........ my boss won't mind, they are so use to me working on knives they are numb to it...!
 
If I get in on this Ganzaa Jeremy, I'll PM you!

So the scotchbrite is just for the finish, not the removal, right?
 
I've found scotchbrite too slow for removal, mine was a 3 inch medium wheel run at 1600 rpm, and only now that's it's worn down to half it's size on one cg FBM is it starting to cut through the decarb. I'd say sandblasting would be the way to go if it has corrugations, 180-220 grit silicon carbide paper or cloth backed sheets if it's flat/convex/hollow ground. Scotchbrite does look nice and is very easy to do as a final finish though.
 
You must log in or register to reply here.
Back
Top