I have this Greek baker friend. Today he asked me if I could re-tin a pot, actually a bowl from an industrial mixer. Apparently once upon a time it was routine to make such bowls from mild steel and tin them to keep them from rusting. But the whisks etc. over the years beat the tin off on the inside and they now say they can't find anyone left in the Pacific Northwest who does re-tinning.
Anyone know how hard this is, and what kind of setup you need? Tinners used to go from door to door, so it seems like it has to be something you can do with a blowtorch and a lump of tin .. ??
Hey Grant. Tin a cooking utensil and you'll be a felon. Both of you, as a matter of fact. Tell your friend to quit poisoning his patrons, open his wallet and buy Stainless Steel.
"John R. Carroll" wrote in message news:Mdtjk.15650$ snipped-for-privacy@nlpi070.nbdc.sbc.com...
?????? I see lots of tinned steel food processing equipment in use----pretty much the standard for older commercial mixers. You have a statute or some other evidence to back up that "felon" statement? I don't hear a lot about tin poisoning either---is it common? How does one become poisoned from a tinned mixer bowl in a bakery?
"First, the old tin is removed from the cookware and the raw copper is prepared to accept new tin. The surfaces are then covered with an acid flux which helps the tin adhere to the copper when heated.
The outer surfaces of the pot are protected with whiting to prevent the hot tin from accidentally sticking to the outside of the pot.
The pot is heated to approximately 450 degrees Farenheit which is the melting point of tin. Pure molten tin is then ladled into the pot and swirled around to coat the desired surfaces. The excess tin is wiped up with a flux coated cotton cloth and the pot is allowed to cool naturally."
"John R. Carroll" wrote in message news:YWtjk.31659$ snipped-for-privacy@nlpi066.nbdc.sbc.com...
John R. Carroll
I think you are confusing "tinning"----a soldering term for applying a thin coat of solder (lead based or otherwise), with Tin---an element, atomic number 50, symbol Sn.
The tinning process on mixing and kitchen utensils uses Tin, NOT an alloy of lead and zinc.
WHAT? TIN IS TIN. It is a base metallic element. Not an alloy.
No Lead and no Zinc in it.
Pure tin is used to line 99% of the copper pots used in the world, and any plain steel is also tin lined. It is also used to line the storage tanks and most of the systems in many water treatment plants. Why? It is chemically inert in the presence of water and does not taint it as it is processed.
Basically you need a source of PURE Grade "A" tin. Then you need a tank/bucket or whatever large enough to hold the pot. You will also need some good flux and a large heat source capable of over 450 degrees.
To do the process itself you need to CLEAN the pot very well. Then mix a dilute solution of Sulphuric Acid to use as a cleaner. Toss the pot in there to clean off and loose tin and to etch the steel and clean it. Now you bring the pot out and wash it VERY WELL in distilled water (keeps any stray chemicals off the steel). Now for the tinning process. You need to heat the pot so the tine will melt. You then wipe it down with the flux and heat it back up. Then use the pure tin and wipe the HOT surface with it so a thin coating is formed. Then use a CLEAN stainless brush to level and flow the tin. Let it cool slightly and wipe it with a dampened rag to smooth it out and cool it more.
Once you have the surface fully tinned you just let it cool down, give it a good washing and put it back in service.
The current local pricing here is about $4.00 per inch. A 24" diameter by 30 inch deep pot runs about $336.00
For a local place look for an outfit that does silver plating or ask one of the resturant supply outfits that sell copperware. 99% of copperware is tin plated.
OK. We have established that tin is tin, not lead + zinc. We have also reprinted the instructions for tinning a copper pot.
This is a steel mixing bowl. I know where to buy things like sal ammoniac or 4% silver 96% tin solder. I have no idea how to saturate a cotton cloth with flux - sal ammoniac is a powder, right? What is "whiting" and where is it sold?
Tin is tin. 50 electrons, 50 protons, somewhere around 69 neutrons if you buy it from a reputable vendors and not those glowing guys who hang out in Hanford. It's been known ever since folks started making bronze from copper and (get this!) tin!
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There may be some alloy of lead and zinc that's called 'tin', and thin sheet steel is called 'tin', and making a thin coating of solder (which is often tin and lead, but not always) is called 'tinning', but those are just colloquial names that mislead one from the basic fact:
'Can't help on where it's sold for *this* application. In comes in various grades and grindings. As for what it is, it's chalk: calcium carbonate. (But most of the sticks of blackboard chalk sold today are actually calcium sulfate [gypsum]). Calcium carbonate is sold as a pH buffer for swimming pools, which is where I've bought it for use as an abrasive and as a component of Swedish Putty, which I mix up from time to time (chalk plus boiled linseed oil).
If tinning with pure tin is anything like all the other soldering jobs I've ever done, doing it to steel is pretty much the same as doing it to copper, only much more fussy about how clean everything must be. I'd wear rubber gloves -- not to protect myself against flux, but to keep the surfaces CLEAN.
I'd also play around at home with some sheet steel to make sure I really understood the process before I went and messed around with the tools of someone else's trade.
Like everyone else here, it appears that I have a clue (and an opinion), but not much more.
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