Comestible Polymeric Coatings Comestible Polymeric Coatings kenmathias (Mechanical) (OP) 8 Nov 10 20:51 Will this type of coating work on other metals such as brass or bronze? RE: Comestible Polymeric Coatings unclesyd (Materials) 9 Nov 10 14:45 I'm pretty sure they will work, but why do you need this type of coating?Food products are generally coated in copper vessels and there is always sticking problem. You should check with your provider as to the type and are there any coating problems on copper alloys. You probably want get a definitive answer as there are too many coating out there. RE: Comestible Polymeric Coatings kenmathias (Mechanical) (OP) 9 Nov 10 21:34 I have a bunch of questions do you have an email address? RE: Comestible Polymeric Coatings unclesyd (Materials) 9 Nov 10 22:00 Please use this Forum to ask your other questions and you should get more and better answers. RE: Comestible Polymeric Coatings kenmathias (Mechanical) (OP) 10 Nov 10 07:32 Brass has lead in it. Would a coating work on a part made of brass to prevent the lead from leaching into water? RE: Comestible Polymeric Coatings unclesyd (Materials) 10 Nov 10 08:54 Brass should have no lead in it. Brass is an alloy of Copper and Zinc and is use extensively in potable water supplies. Are you talking about leaded bronze? RE: Comestible Polymeric Coatings kenmathias (Mechanical) (OP) 10 Nov 10 09:47 There is no lead in brass? There is a reason why I am asking the question. In California laws are being passed as we speak to change what types of materials are used in the Plumbing industry. RE: Comestible Polymeric Coatings unclesyd (Materials) 10 Nov 10 11:59 Brass is mainly an alloy of Copper and Zinc and should have no lead. Brass has been used for potable water for many years and the only complaint is that in some water the fittings will turn green. This was mitigated by plating with Cadmium, very bad and later Nickel, until the price got too high for normal fittings. One other problem with Brass you have process called, Dezincification, if used in very pure water. This is where the Zinc and Copper dissolve and the Copper plated back on the brass fitting.What specifically are they trying to prevent with the new laws?Need a little more detail of why you are worried about Lead?If you are machining a part you can get a Material Test Report on your starting material that list every metal in the composition. If the parts already exist there it would be extremely hard to get tracer on the material. RE: Comestible Polymeric Coatings kenmathias (Mechanical) (OP) 10 Nov 10 21:14 http://www.copper.org/resources/properties/db/SDResultServlet.jsp?Action=search&service=COPPERINTRA&ACtype=Wrought&Alloy=Brasses&term=Copper-Zinc-Lead%20Alloys%20(Leaded%20%20Brasses)&alloyStart=C30000&alloyEnd=C39999see the link above. There is lead in brass. RE: Comestible Polymeric Coatings unclesyd (Materials) 10 Nov 10 22:39 Yes you can get almost any Copper Alloy with Lead, but why would you use it?I should have made it little clearer when it comes to brasses for potable water service. The brasses used have only tramp amounts of Lead, 0.05% for a lot is the max Lead allowed. I worked for foundry that produced brasses for potable water service and in the three years that I worked there Lead was reported undetectable using the chemistry of the day. When the company later got an emission spectrophotometer the amount of lead found was < 5 parts per million. Do you have the permissible limit for Lead per the new standard? RE: Comestible Polymeric Coatings unclesyd (Materials) 11 Nov 10 20:48 Check the full text of this paper at the AWWA site referenced. http://www.physorg.com/news/2010-11-brass-devices-plumbing-lead-in-water-problems.html RE: Comestible Polymeric Coatings dgallup (Automotive) 12 Nov 10 12:33 Good grief, what did they use & where did it come from?"The problem eventually was traced to a source in the building's piping system upstream of the water fountains. The cause was a particular type of ball valve and the problem disappeared when the valves were removed. The valves were later found to have as much as 18 percent lead by weight on the inner surfaces contacting the drinking water. Later testing proved the valves would leach lead at levels high above the EPA standard for months."Even free cutting leaded brasses don't have anywhere near that much lead. RE: Comestible Polymeric Coatings kenmathias (Mechanical) (OP) 12 Nov 10 14:53 No now between 2 and 5 percent which is still to much. So will this coating work? RE: Comestible Polymeric Coatings dgallup (Automotive) 12 Nov 10 17:18 I think they can be applied but that does not mean they will "work". If you are thinking about using them in valve bodies I expect they would wear through in short order, exposing the base metal. Screw threads might last the first use but then it would be destroyed if the fitting were reused. I think something like electroless nickel plating would be better.There are lots of brass alloys without lead, wouldn't it be simpler to use them? They won't machine as easily as leaded brass but they still are not hard to machine. RE: Comestible Polymeric Coatings unclesyd (Materials) 12 Nov 10 19:53 I don't know about how much lead will be allowed in brass, but with ceramics, lead anywhere is counted. The slip that an article is poured with can have no or extremely low levels of Lead. The glazes or any paint sor such article can have none.I suspect that the new law will apply to the base metal and will not be mitigated by any coating. As stated above at one time we plated a lot of fittings with Cadmium for aesthetic purposes. During the same period all galvanized fittings and pipe contained appreciable amounts of lead. The intent of the law is to prevent ingestion of Lead in any form and I don't think anyone will appreciate any attempt to cover up a leas containing material. I would definitely get a understanding of what the new law allows and until it's clear use a lead free brass, as suggested above. RE: Comestible Polymeric Coatings kenmathias (Mechanical) (OP) 12 Nov 10 21:32 When trying to keep the manufacturing in the united states every second of cycle time counts. And cycle times go through the roof in no lead/low lead brass especially in I.D. Work.