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I picked up an Emerson CQC-7 "Mini-B" with satin finish. Great little folder, but I was wondering how durable is the silver coating compared to the basic Black-T? Does it wear the same?
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Question on Emerson hard chrome finish.
- Thread starter Cosmic Superchunk
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Thanks Holden. It's an attractive finish that looks better than my older bead blasted CQC-7B. Other than Emerson Knives, I haven't seen any others using it. Is it a proprietary coating only used by Emerson?
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I think Busse also applies a hard chrome coating to its blades. Don't think it's proprietary. The coating is supposed to bond pretty well with the blade steel.
It's not a proprietary coating. I've seen it used on other knives, and tools for that matter. It holds up really well with light-moderate use. The only problem I've had is the coating chipping off while prying with the knife, or when the knife strikes a hard surface. This is not too surprizing though. In my opinion, hard chrome is the best non-black finish I've seen. Looks good, lasts a long time.
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Thanks for the update guys. 
rfrost, I'm not saying you are wrong but I don't understand how ceramic coatings can strengthen blades? If my understanding is correct, ceramics are rather brittle and would tend to crack or chip from a blade that is flexed or impacted with another hard object.
Just looking for some clarification. Maybe you know something that I don't... Thanks.
Just looking for some clarification. Maybe you know something that I don't... Thanks.
Holden,
I am not an expert in this, but about the ceramic coating, perhaps it would relatively strenghten the blade because it is harder then steel itself, and thus form a harder outer coating? sort of like a laminate effect?...just guessing on my part though...
I am not an expert in this, but about the ceramic coating, perhaps it would relatively strenghten the blade because it is harder then steel itself, and thus form a harder outer coating? sort of like a laminate effect?...just guessing on my part though...
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The Emerson hard chroming is done by a friend of mine. He first tried hardchroming blades on 3 of mine from other manufacturers. He told me that the hardness is equal to about RC 73. I've been using my hardchromed blades since a couple years before the process was adopted by Emerson, and it holds up well. If a blade ever became badly scratched up, it might even be possible to send it to Steve for re-chroming (but I'd need to ask him).
DWK, would it be possible to ask your friend, Steve, if the hard chroming he applies is somewhat permeable? I've never had a problem with the coating on my Emersons but I did hear elsewhere that a certain "...pure chromium [coating] is porous in and of itself." TIA.
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Brian,
It may take a few days to catch up with Steve, but I'll be glad to ask. I've heard that hardchroming is used for a lot of different reasons (like lubricity on bearing surfaces), but corrosion resistance is a common reason for doing it on firearms. Significant porosity would seem inconsistent with that attribute, but I'm not a metallurgist so I won't speculate.
I'll be back in touch.
It may take a few days to catch up with Steve, but I'll be glad to ask. I've heard that hardchroming is used for a lot of different reasons (like lubricity on bearing surfaces), but corrosion resistance is a common reason for doing it on firearms. Significant porosity would seem inconsistent with that attribute, but I'm not a metallurgist so I won't speculate.
I'll be back in touch.
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Brian,
Well I just spoke with Steve and my (incorrect) speculation above shows why it's not a good idea to guess before talking with an expert.
Steve said that hardchrome is so hard that a number of microfissures exist in the material. That creates the porosity about which you asked. Despite the fact that hardchrome has some porosity, hardchromed metals still seem to fare better in weather tests than comparable metal without the hardchrome. However, to get the maximum corrosion resistance for environments like saltwater, Steve said that you need to coat the metal with sulfamate nickel before applying the hardchrome.
Steve stated that additional benefits of hardchroming a blade include much better scratch resistance and higher lubricity. As you would assume, the higher lubricity means that the blade surface is more "slippery" so it slides through the material being cut with less effort.
I asked Steve about re-chroming a blade and he said that it is possible for his company to bead blast a blade then re-apply hardchrome. However, since the chrome is harder than the underlying steel (into the C70+ range), any scratches that get through the chrome are likely to have an impact on the steel. Therefore, the steel would probably require polishing prior to re-chroming, in order to assure a smooth finish. I didn't ask him, but all of that sounded expensive.
I hope I have accurately conveyed what Steve told me and, if you have any further questions, I expect to see him next Thursday at the Adventurers' Club, Los Angeles, for the weekly program.
Well I just spoke with Steve and my (incorrect) speculation above shows why it's not a good idea to guess before talking with an expert.
Steve said that hardchrome is so hard that a number of microfissures exist in the material. That creates the porosity about which you asked. Despite the fact that hardchrome has some porosity, hardchromed metals still seem to fare better in weather tests than comparable metal without the hardchrome. However, to get the maximum corrosion resistance for environments like saltwater, Steve said that you need to coat the metal with sulfamate nickel before applying the hardchrome.
Steve stated that additional benefits of hardchroming a blade include much better scratch resistance and higher lubricity. As you would assume, the higher lubricity means that the blade surface is more "slippery" so it slides through the material being cut with less effort.
I asked Steve about re-chroming a blade and he said that it is possible for his company to bead blast a blade then re-apply hardchrome. However, since the chrome is harder than the underlying steel (into the C70+ range), any scratches that get through the chrome are likely to have an impact on the steel. Therefore, the steel would probably require polishing prior to re-chroming, in order to assure a smooth finish. I didn't ask him, but all of that sounded expensive.
I hope I have accurately conveyed what Steve told me and, if you have any further questions, I expect to see him next Thursday at the Adventurers' Club, Los Angeles, for the weekly program.