Bead-Blast = Bad Stuff ?

B

Bill McWilliams

Joined
Oct 3, 1998
Messages
811
The ONLY knives I own that have ever stained or rusted are those with a blasted finish. There is one exception, though. My Vero Beach autos have a smooth bead blast finish on 440C steel. They have been through hell and back and look great.

I have a Spyderco Mini-Police neclace that is satin ATS-34.
It goes into the shower daily and gets soaked with sweat as well as starch from my business shirts. Never gets wiped off and still looks great.

The point I'm making is that it appears that the steel itself is not the problem. It's the finish. Accordingly, why do we have so many bead-blasted knives out there ?
Bill

BTW: All blades have been wiped and maintained with Tuf-Cloth
 
Bill,
I agree with you 100%!! Many of the kives I make get bead blasted, and yes they rust and stain more because of it. I bead blast only to satisfy customer requests. I explain what happens to the finish to the customers but they want it anyway! Why anyone would want a bead blasted hunting kife is beyond me......
The deer cant see the reflection when it's in the sheath, inside the hunting pack!!! The knives that leave my shop bead blasted are the only ones that ever come back!!! To be re-blasted!
 
Bead blasting is out there because the market demands it. Corrosion resistance is reduced greatly by roughening up the surface. In other words the best finish for preventing corrosion is a full mirror, the worst is a bead blasted finish.

It takes a really good steel to resist corrosion after bead blasting.

The public gets what it deserves I guess.

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george
www.tichbourneknives.com
sales@tichbourneknives.com



[This message has been edited by george tichbourne (edited 04 September 1999).]
 
It depends on the media and pressure used during blasting. Sand and Aluminum oxide grit cuts the steel opening up the pores to moisture. On the other hand, the auto you talk about was probably blasted with new glass beads and peened the finish rather than cutting it. I am using ceramic beads on A-2 knives and the ceramic seems to hammer the grain shut and these knives are noticeably harder to rust. This is my limited experience.

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www.simonichknives.com
 
Couldn't agree more... It's become standard practice for me now to take some metal-glow and rub the finish off these knives, just to the point it has a slight shine to the balde...Problem solved! It seem's to really put an end to the rust problem. You should see my CRKT M16 now, It's got shine that I can almost see myself in
smile.gif
. I've seen the same problem on a Benchmade CQC7 too, so it's not just in the price you pay for a knife.




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~Keith~
"War to the knife and knife to the hilt"

 
I was always under the impression that companys bead blasted their blades because it is easier/cheaper to do than to satin finish a blade.

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Johnny
[]xxxxxx[]=============>
 
Yeah, but bead blast is great to cut glare as you stalk a sentry to slit his throat...
wink.gif
What's that, all these tac!@#$% (whoops, almost said the t-word)folders aren't sold to high speed low drag special forces recon seal ninjas ? I refuse to believe that form doesn't follow function in the cutlery industry
wink.gif


[This message has been edited by Root (edited 04 September 1999).]
 
Johny,
Bead blasting and Tumbling (stonewash)finishs don't hide very much! Both processes remove or Peen in about the same amount of material. In order to get a good bead blast finish, no grind lines etc., I spend alomst as much time as satin finishing before I beed blast. A good example of not covering grind marks is on the Nov. issue of Tactical Knives. Nothing against REKAT, I ordered a SIFU!!!! But the factory Carnivor on the cover has its grind lines showing through the stonewash finish. It is even more pronounced in the picture on page 10!!!!If I presented one of my knives to one of my regular customers looking like that........
Bead blasting and tumbling wont even hide a Rockwell mark!!!!!
 
Well,
Here's another take on the bead blast thing. The mirror finish on my custom knife purchases are awe inspiring in their beauty. Too beautiful to use in fact and therein lies the rub.
Personally, when I buy a knife I want to use it and I just cannot bring myself to take the chance of scratching the beautiful finish on an expensive custom made knife.
Take the same knife and put a subdued finish on it and I don't have near the aversion to using it that I would if it still had that wonderful mirror polish. I guess I'm like a crow and I like shiny things.
For this reason I have knives that will never see a days' use.
Now I totally agree that a mirror polish will always have better corrosion resistance than a bead blast finish but in my case a mirror finish precludes a knife from being a using knife. Pretty damn silly huh?

------------------
If it's stupid but works, then it isn't stupid.


 
Try the ceramic bead that Rob is talking about. It peens the finish and doesn't cut it like broken glass or sand. Leaves a finish that will bead water.
Saves time? I don't think so. I go to a 400-500 grit finish before I bead blast. It doesn't "cover" anything.
 
While I agree that there are a few folks doing very nice, fine bead-blasts out there, the bead-blasts used on most factory knives are rougher and have the ability to hide a great deal. A thorough bead-blast can hide a blurry grind or the marks from a fairly rough finish. Perhaps the reason that we don't notice this so much is that we have come to accept grinder marks in the 220-320 grit range as a "satin" finish. These finishes are not "satin" and they are also not very rust-resistant, just like bead blasts. To give some idea, I've seen rust form in minutes on ATS-34 ground only slightly rougher, just due to exposure to pure water and heat.

I know that bead-blasting can slightly peen the material surface, which theoretically hardens it further to resist corrosion. But this effect is minimal compared to the increased surface area and the massive potential created for corrosive agents to become trapped in the rough surface when on a mirrored surface they would be wiped away with ease.

Bead-blasting is an easier finish to apply than a good satin or mirror. Anyone disagree? I feel this is what has driven its popularity. Talk of low-reflection is nonsense; every opinion I have seen from military personnel agrees that by the time the knife is out of its sheath, reflection is not a concern. Furthermore, what percentage of these knives ever get sold to the Military, and what percentage of those that are will ever be used in such a role?

I know that there are some makers who this will anger, but I see bead-blasting as an easy way out of properly finishing a knife. If an easy non-reflective coating is desired, many coatings will hide some grinding marks and also eliminate reflection without opening the knife up to corrosion. I'm willing to consider everyone's opinions and reasoning on the matter, but so far I see no reason other than economy to pit the surface of a perfectly good knife.

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-Drew Gleason
Little Bear Knives
 
I did the "rest" job on my BM 975 for Benchmade. The blade got coloured brown in my front pocket within a daytime carry, and the colour seemed so sticking I couldn't polish them off the blade without damaging the bead blasted surface. At last I decided to polish off all the rust with bead blasted surface altogether.

I started to polish... within a minute I found out rough grind marks showing on its surface but too late then to get back.
Finally I had almost successfully my BM975 hard to rust that reflects my face in it for the cost of hours of sweat and BM warranty.


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\(^o^)/ Mizutani Satoshi \(^o^)/
 
for once i wont argue..everyone is right... the major reason for rust in bead blast is the depth of the crater....sand or garnet vs very fine glass etc...they even have plastic beading media.....the reason the industry uses it...come on....$$$$$$$$$$$$$$$$$$$. they are saving money...dont have to get a nice finish....just blast away with coarse beads......didnt read all the posts but the harder the material the more it resists rust...paul bos also told me that when 440c is tempered below 56c the corrosion resistance goes out the window...dont know about other steels but would imagine this is probably true for a lot of the high chromium steels...

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http://www.mayoknives.com


 
Response + Question:

I believe that bead blasts/satin finishes are so popular because:

a) Some have bought into the idea that there is a great tacticle advantage to the cut in reflection,, by gun/knife writers.

b) Others just like the look of a good satin/bead blasted finish better than a good high shine polish.

I happen to be one of those people, that in spite of the advantages of the polished surface, just like the satin finish better on my hardware. It makes very little, if any, sense to have that kind of finish. Its just more asthetically pleasing to ME. What I find more visually pleasing, tends to spend more time in my pocket/waistband; so it gets used more and becomes my friend. My favorite finish is a satin finished high carbon steel that's hot blued. YeeeeeDoggies what a beauty!!!
smile.gif
I'm droolin just thinkin 'bout it. I can't see my ugly reflection in it, but I can see a rainbow of colors.

QUESTION: Does anyone know:

a) How does a aluminum oxide blasted blade look coated with TiCarbonoNitride or TiAluminumNitride?

b) Would these coatings eliminate the posibility of corrosion when exposed to nothing more than perspiration?

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"But now, he that hath a purse, let him take it, and likewise his scrip; and he that hath no sword let him sell his garment and buy one." Luke 22:36 & John 3:18
 
I just wanted to put on my .02 I make all of my knives with a blasted finish. I have sold many knives, to many customers, all over the world. I never get complaints of rust. My knives are ATS-34. They are flat ground, so I feel confident with the blade being harder. The harder the steel, the better the rust resistance (apples to apples). I carry one of my knives at all time. I live in Oklahoma, in a very humid area (Tulsa area). I use my knife regularly. I have never had a problem with rust. I have customers, that use my knives for skinning. No complaints from them. The great thing about blasted, is that it can be reblasted easily. So if you do manage to mess up the finish, the maker can fix it for you, cheap. I beadblast for 2 major reasons. #1, it is what sells best for me. #2, I like the way it looks. People say a beadblast is easier. It is not difficult once you get all the details worked out. It took me over a year, to get everything lined out, to be able to do it consistently. I also would like to point out, that blasting, will not hide funky grind lines. It also will not hide deep grinder gouges, or grit marks. Also a there is a major difference between different makers beadblasted knives. Don't judge them all, by a few bad ones, or good for that matter, that you have seen. Different makers, but different amounts of time, into there knives before, and after they blast. Same thing with makers that satin finish, or mirror finish. I would put a properly heattreated blasted ATS-34 blade against 1095 or O-1 with a mirror finish, for rust resistance any day of the week.
Sorry for the rant.

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Lynn Griffith-Tactical Knifemaker
Winner of "Best Tactical Knife" at 1999 PKA show
My website
See my award winning "Spec Ops Tanto" in Gallery 3 of my website
GriffithKN@aol.com

 
One point about bead-blast vs satin finish that I haven't seen anyone make is that the satin finish just seems to cut better. If i take a satin finished blade and cut some cardboard it is easier than cutting with a bead blasted knife of the same configuration. The sides of the blade being rough really seems to add a lot of friction cutting some materials. I've noticed this with food-prep too, especially when cutting something like a winter squash or a melon.

Just thought I'd throw that in.
 
Point to Mr. Griffith on the easy re-finishing.

I'm starting to feel as though we're having a "prop planes versus jets" conversation, with no regard to the variety of either type. There are a variety of blasting media available, and a variety of blasted finishes. Perhaps we should not judge all equally.

Folks know a great deal of my time has been spent working with or on Benchmade brand knives. These are generally ATS-34 at about as high a hardness (61Rc) as anyone feels is practical. Nevertheless, they get rust-spotting with relative ease, even in their "satin" finish. I've disassembled bead-blasted models straight from the factory that showed rust on areas of the blade (though not the pivot area, which is smoothly finished). Perhaps this is the "ugly end" of bead-blasting - it has certainly prejudiced me against all forms of the finish. For my own knives, I use at least a medium Scotchbrite wheel for a "working" finish that won't pick up corrosion from fingerprints and assorted gunk, and prefer a mirror finish whenever it looks appropriate.

The testimonies of folks like Mr. Carson have me somewhat shaken, though. Curious to hear from more makers.

-Drew
 
Drew,
I actually tell my cusotmers, to go use there knife. Don't worry about scratching, or hurting the finish. If you mess up the finish, I can fix it. I tell them, about $10 + postage, to reblast and mark the knife. I will sharpen he knife to new, while I have it. I want my knives to be used. I love it, when a customer shares there knife stories with me. I make using knives. I don't want a worry, about the finish, to discorage use of my knives. When I sell my knives to police officers, I know the knife will get wet. When I sell the knife to hunters, I know the knife will get bloody. When I sell the knife to military, I know they will probably use it hard. I want them to all know they can use it. Being able to have a knife brought back to new, relieves the fear of using it. Espescially if they can have it, back to new, with very little expense. How some feel about beadblasting and blood, I feel about stag and blood. Or pearl and keys. Or wood and water. Or leather and carbon steel. Or leather and water. Or ivory and time. You have a give and take with any option you choose,on a knife. The key I believe, is knowing what you need the knife to do, and buying the knife, that will do that best.
Drew, BTW, Your insights show intelligence, and are appreciated. Don't ever consider it personal, when I have a difference of opinion.


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Lynn Griffith-Tactical Knifemaker
Winner of "Best Tactical Knife" at 1999 PKA show
My website
See my award winning "Spec Ops Tanto" in Gallery 3 of my website
GriffithKN@aol.com

 
Lynn,
I have seen your knives and have the utmost respect for your work!!! I am not trying to provoke an argument here!!
I am a virtually unknown, part time knifemaker. However, I make and sell an average of 3 knives per week. I dont advertise, have a website or do shows. I have to provide my customers with what THEY want in a knife as far as finish. Less than 10 percent of my knives are bead blasted. I mirror finsh, satin finish and quite a few blades have a combination finish (mirror hollow grinds, hand rubbed flats) I use a photo masking process in order to sandblast my logo and any personalizations the customer might request! So all my knives wind up in the blast cabinet, no matter what the blade finish is!!I stand behind all my finishes on all the materials I use including carbon steels. I will re-do any finish and resharpen for a reasonable price.
If I was going to offer one steel and one finish, bead blasted ATS-34 would be on the top of my list! My customer base just would not accept this, however, I think I am going to limit the bead blasted blades to ATS-34 and D2 from now on!!!
This has been a good topic, on a good forum!!
 
Dr. Lathe,
I apologize, if I came off, as being argumenative. That was not my intention
I also apologize, if any materials reference(that I made), was taken as a cut down. I think that all of the cutlery steels in common usage, have there place.
I was just stating my experiences with blasting, and ATS-34.
I 100% believe that you should give your customers, what they want, from you. This is also what I strive for. I do not encourage anyone to do, what works for me. I encourage them to do what works, for them.
I appreciate it, that you respect my work. Coming from a knifemaker, that is a fantastic compliment. That would be a fantastic compliment from anyone.
If convenient, I would love to see a scan of your work sometime. I promise to show you the same respect, you have shown me. I know your work must be good. If it were not, you would not have people buying it.
You are also, welcome to e-mail me direct. I would be happy to talk knives with you anytime.

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Lynn Griffith-Tactical Knifemaker
Winner of "Best Tactical Knife" at 1999 PKA show
My website
See my award winning "Spec Ops Tanto" in Gallery 3 of my website
GriffithKN@aol.com

 
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