View Full Version : Making "food-safe" items
07-03-2007, 12:16 AM
The thread about lathe-turned cups got me thinking...
Back in my college days, guys would often make aluminum or brass shot-glasses and cups in the machine shop. After polishing them, they'd cover them with auto-body clearcoat to preserve the shine. I can only imagine that there are health problems associated with drinking from those glasses. So, when you guys make items that come in contact with human food, do you take any special precautions? Do you coat the finished product with something or do you just wash it and call it done?
Thanks for any help you guys can provide.
07-03-2007, 02:01 AM
Removed - double-posted - see next post.
07-03-2007, 02:19 AM
07-03-2007, 02:29 AM
brass is a baddie, as is straight copper. Both need silver plating (or some other type of non-reactive coating) to allow them to be food-safe.
Aluminum has a baddish rap these days, and also corrodes.
have not dealt with that for machined parts, but metalsmithing/metal sculpture, there I have had to.
07-03-2007, 02:52 AM
As J Tiers said, copper & brass should not be exposed to foodstuffs. In plumbing we have been using lead-free solder for years on potable water piping. In fabricating/ repairing commercial food equipment it's almost all stainless steel of one type or another. (316, 316L) usually tig welded. Some types of plastics are approved for piping to handle food products.
I have a few customers in this field, and the jobs are always a pain since the customers often can't/ won't understand the expense of the materials used.
Even making bakery pans (think large roasting pans) from stainless sheet, they bitch at the cost and I try to use them as fill-in jobs.
07-03-2007, 02:58 AM
I was reading about tin cans awhile ago. Seems they are coated on the inside with epoxy, the same stuff that's used to coat burls, coffee tables, etc. One such product is called Envirotex, another one is called Nu-lustre 55. If this stuff is safe for food that's in contact with it for months, sometimes years, it probably is food safe. Think of what else we use as containers to handle our food and drink- styrofoam, styrene, polyethylene, aluminum (foil), iron, rubber, lexan, enamel, silicon and urethane, vinyl- the list goes on.
I would have no problem drinking rye wiskey out of an epoxy coated brass cup, I'd probably want it to cure for a week or so first.
07-03-2007, 10:14 AM
surely your pots and pans are made from mild steel or aluminium or stainless why should this be unsafe ?Alistair
07-03-2007, 10:40 AM
I guess gold would have to be the metal of choice if you want to be non-reactive, but sometimes you want to be reactive, Silver would be the bomb as it is reactive but generally in a positive way, it's been used for eating utensils for century's for good reason, it kills almost all virus/bacteria/and most molds and fungus that come in contact with it within about 4 minutes,
All the space shuttles plumbing is lined with it for this reason, Most major airliner water filtration systems use it in thier filter medium, And in its colloidal form it has some very powerful effects systemically and I can personally attest to that --- argyria is the only real documented side effect (blueish discoloring of the skin, and the reason the "royals" got the nickname "bluebloods" because back in the day they were the only ones who could afford silver and they used it for everything and used to grind it up and eat the powder) Argyria is about non-existant in the pure colloidal form, its very safe and the better the colloidal "brewer" you have the better it works and also the lower the risk as the particles are kept very small --- So if i had to build a goblet, I would want one of both silver and gold, save the swarf...
07-03-2007, 01:19 PM
Along similar lines, I needed gold and silver plating capability years ago for some electronics work. The chemicals involved contain a small amount of sodium cyanide. I still have that capability and thought about some jewelry uses. However, I recall seeing something in passing (maybe at a clean freak or greenie website) about concerns with cyanide-based plating in contact with the skin. So far, I have not been able to relocate the information. Any ideas?
The supplier I originally purchased from no longer sells plating supplies.
Seems other plating suppliers are pushing the "safer" non-cyanide processes. Not unreasonable from an economics point of view, as shipping is cheaper. Still, I wonder if there is any prohibition or rule about cyanide-based plating.
As far as i know, (which may not be very far), the top gold-platers in the country still use cyanide based gold. I run a small gold-plating bath, and sometimes i may have to reach in to rescue a part that's fallen off it's wire. A quick rinse, and all is well. I've never had any serious skin reaction to this, even though the purple liquid may be in contact for thirty seconds or more. Obviously you'd need to clean it off before eating your sandwiches:-). Email me if you need any more details.
Richard in Los Angeles
07-03-2007, 11:03 PM
HOW MUCH CYANIDE IS IN THE GOLD PLATING SOLUTIONS? The amount of cyanide hinges, generally, on the actual amount of gold in the solution. The actual gold in the gold plating solutions on the market today run from 1/2 an ounce to a gallon up to 4 ounces to a gallon. The average seems to be about 2 ounces to a gallon.
The gold plating salts come from one of several companies providing gold to the different distributors serving the Mobile, or BRUSH, Plating Industry. For each ounce of gold "metal" there is, approximately, 1/2 an ounce of cyanide.
So, in a solution of 2 ounces of gold to a gallon (a gallon = 128 ounces) there is, potentially one ounce of cyanide. Or, 1/128th of the whole.
My two quarts of the stuff adds up to a half ounce. My original question concerns whether and how much will be transferred to jewelry or perhaps a pen ferrule or clip, and if any will remain after a thorough washing after plating. What was common practice only a few years ago may be considered hazardous today. Look at the unreasoned and uninformed fear of anything with even a trace of lead, mercury or asbestos content. Now, I don't advocate a cavalier attitude about such things, but I think that most reactions to "spills" are overblown. Probably because somebody has found it profitable to stage overreactions.:mad:
I think society has lost most of it's common sense.
07-03-2007, 11:57 PM
Oldtiffie is on the right track...I say enough rum will render anything safe.