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Letter 854 Hot vs. cold black oxide--- I work in a tool room as an apprentice and would like a comparison of durability between black oxide done with the cold method and the hot method. thank you very much. Thomas M. Herpel -
--- Room temperature blackening with proprietary solutions is more expensive and less durable, Thomas, and doesn't look as good. However, hot black oxiding is a nasty, dangerous, process. So, if the durability of room temperature blackening is sufficient for you, and the cost is affordable, it is certainly worthwhile. How much less durable, I can't say without doing a literature search though, and whether "durable enough" would depend on the application. Good luck!
--- Tom, Ditto on what Ted said. A well done hot process looks a lot better and my gut feeling is that it is ten times as durable as a well done cold process. The cold process is adequate for most of the tool room uses. Have done both and unless you absolutely need the better protection of hot, use the cold. Hot is going to cause you some problem with EPA more so than the cold. Personal feelings. James Watts Ed. note: Please see our FAQ on Black Oxide & Cold Blackening.
-- I'm very interested in the cold process for auto parts for personal use and want to find a local dealer for the chemicals. However I have the background to set up a small garage based unit for local hot rodders. any help will be appreciated. john g.
If you do, that will make you a Hazardous waste generator. suggest that you check with your region of the state EPA and with your local sewer folks before you go any further. You probably will change your mind. Minimum fine is about $500 up to a max of $25,000 per violation, per day if you are caught. If an angry customer turns you in, they will visit you, to clear the complaint. James Watts
+ James, Which process would make me more of a hazardous waste generator, the hot method or the cold? Do you know of any documentation comparing the waste concerns of both methods? Bob P.
+++ Response to John G. If you really have the proper background to install a mini plating shop in your garage, then you know full well you will be exposing your children, pets and neighbors to dangerous chemicals. You should also be aware that you will have chemicals and waste water to dispose of, and that you need a city permit, a state permit and EPA clearance to do all of this. Are you prepared to put in a separate sewerline, pay the business fees and license fees to all the proper agencies, or are you just out to make a fast buck, pollute the waterways, and take the livelihood from an honest, reputable plating shop that does all these things. Lee Garcia
+++ You people make way too big a deal out of this EPA stuff. I've been plating copper and nickel, and anodizing aluminum for YEARS in a very visible, well known shop 1 block from a county wastewater treatment facility, and have NEVER EVER EVER even spoke to one single EPA or any other agency representative. I have no special sewer line, nothing. I collect any wastewater I have in HDPE 50 gal drums and have it picked up by a local environmental service company who disposes of it for a fee. Stop trying to discourage people from getting into the hobby by throwing a bunch of legal mumbo jumbo at them. Why even bother to have this forum if all your gonna do is try keep all this century old plating stuff a "secret" just so you can make more money? A small 2-5 gallon plating line can be built any where, garage or basement included. Mike Horan
+++ You are welcome to your opinion, Mr. Horan and, as you see, we are happy to publish it. What good is this forum if it doesn't encourage hobbyist plating, you ask? Well, what good is a police force if they don't serve me breakfast in bed? And what good is an air conditioner if I can't barbecue a steak on it? The purpose of this forum is not focused on hobbyist plating, nor directed at tempting people to injure themselves, violate laws or jeopardize the public safety. If you operate a plating shop, please glance through 40CFR, especially the subheadings on waste water, sludge accumulation, nitrate generation, and air emissions estimating. Go to a hazmat course offered by AESF, or Lion Technologies, or your local community college. Go to the library and read a couple of issues of Plating and Surface Finishing, Metal Finishing, or Products Finishing. Attend the annual AESF-EPA meeting in Orlando. And then explain to yourself under what grounds you think you became exempt. Or simply call your local chapter of PIRG and tell them about yourself.
++++ Curiosity has me in it's grip today. I do gunsmithing once in a while. So far, sending parts out hasn't been too tough, but I'd like to add to my in-shop abilities. Some things MIGHT be better if I had some control over them myself. Getting parts back plated too thick, or not masked properly... I found, well, Ted's response a bit presumptuous, and rather inflammatory. Ya, it was a flame...but a semi-informative one. Listed a few areas for me to look into... Being interested in the plating/finishing processes, I'd like to know more about the laws involved, and what needs to be done to actually DO some plating/finishing on my own once in a while. Truth be told, it's MY judgment call as to what will be "too expensive" to justify it. Likewise with the legal research. It's MY responsibility to ensure I conform with law, specifically those that would apply to ME: MY application, quantities, location, whether to hire a lawyer to find all of this out, etc... Case in point: Some businesses ARE EXEMPT from OSHA. Law is not always the same, it's up to the individual to make sure they comply to whatever laws applicable. Real Estate businesses are exempt from OSHA, BTW...Supposedly not enough injuries per year to justify inspecting them...Hmph... Anyhow, rather than blow someone off with a flame, next time do it with some finesse. Information shared responsibly, AND IN A MANNER THAT IS USEFUL, is worth a lot more than some cheap shot at the auto parts plating guy. Enough to think about. Take Care, Robert Johnson
++++ Your view of this situation, Mr. Johnson, reminds me of the way zealots react to political ads. If they want to agree with one side, then they see that side's ads as "only saying what has to be said" (no matter how vicious and misleading the ad actually is). And they see the other side as engaging in attacks if they challenge any claims at all. James Watts and Lee Garcia warned the initial writers that there are EPA problems involved in this kind of chemical processing. To that, Mr. Horan responded by saying they 'make way too big a deal' of it and were 'throwing a bunch of legal mumbo jumbo' at people. He implied that our website is worthless to the extent it doesn't serve the purpose he wishes. He closed by saying that our motive for the long years we've put into this site was to keep things "secret" so we could "make more money" by discouraging people from the business. Yet you saw none of those deliberate, repeated, provocative, personal insults as a flame!? I then gave the volume number of the code of federal regulations that people should look at, and what subheadings to look under. I gave three places where people could get training if interested. I named the three principal journals serving the industry if anyone wanted to learn more. I told people the location of the annual conference where EPA would keep metal finishers advised of what the regulations actually are. But you considered this as 'blowing him off' and as not sharing information in a 'manner that is useful'. And you characterize my response as a flame :-) Hobbyists often react petulantly when they find that electroplating isn't as easy as they hoped. Oh well. EPA 40CFR413 and 40CFR433 make no exception for the size of a business! However, if someone is processing parts only for personal use and they neither sell a finished part nor their processing services, so that they can honestly say they are not in business, it is probably true that the federal regulations may not apply to them. However, there are still a myriad of state and local laws, and sewer regulations that are violated by that chemical processing. That, as you say, depends on the situation.
January 5, 2007 For your info - Ben Pearson
January 11, 2007 Those steps are the same, Ben. Scale must be removed, then the parts thoroughly alkaline cleaned before putting them in the hot black oxide tank. Usually there will be a post-dip involving a wax or oil. The biggest difference is that hot black oxide is quite dangerous, and operators have been killed. The cause of the problem is that the process operates at about 290 deg. F so there are evaporation losses, and water must be constantly added. But water flashes to steam at 212 deg F. If a slug of make-up water finds itself surrounded by this 290 deg solution, it can virtually explode into steam, propelling gallons of this hot concentrated caustic onto an operator. Extreme care must be used to prevent that from ever happening. Good luck.
Dear Reader: please choose what you want to do.
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