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Step 2Background, & Metalcasting Notes
A few thoughts, tips, pointers.
First of all, there's an excellent Yahoo! group devoted just to the Gingery books, machines, etc. You should definitely check out the Lindsay books (see link in step #1), and the Yahoo group: http://groups.yahoo.com/group/gingery_machines/.
There's a TON of good information and suggestions on the group. Some of the more popular ones seem to be: make the ways (a slab of 1/4" x 3" cold-rolled steel, on which the carriage (the main cutting-tool holder assembly) rides) thicker and thus sturdier; secure the ways to the bed with many more fasteners; and use a modified tool-post/toolholder. There are designs, photos, corrections, bills of materials, etc. (I'll try to add much of that information here, as I'm able.)
Secondly - the Gingery method mostly assumes using scrap aluminum. A few things I've learned:
(A) "Can you use beer/soda cans?" This is often referred to as "beercanium", or some similar funny term. The concensus I've seen, and have experimentally verified, is this: you can't really use JUST beer cans -- aluminum exposed to air instantly develops a thin layer of aluminum oxide (for fun, this is also. in crystalline form, basically ruby!). Beer cans are thin, with lots of surface area, so melting beer/soda cans alone just doesn't really work well (especially since melting tends to produce MORE oxidation.
HOWEVER -- if you melt some aluminum, such as window frames, pistons, etc. -- and THEN drop in some well-crushed and dried beer/soda cans, they'll contribute to the mix just fine.
SAFETY NOTE: if there's ANY moisture left in the cans, you are probably going to witness a SPECTACULAR explosion several milliseconds before losing your vision permanently. I'm not an expert, and if you follow my instructions, you'll probably DIE, be seriously maimed, or end up on some very, very pernicious mailing lists -- do NOT take ANYthing I say as anything other than potentially *very* dangerous activities. YOU HAVE BEEN WARNED.
(B) Using Metals Other Than Aluminum -- this is my personal choice. I cast a few parts out of Aluminum, then switched to a Zinc-Aluminum alloy (called Zamak, among other things).
Why?
Several reasons. (1) Zinc melts at MUCH lower temperatures, in the 700-degree range vs. 1,400 degrees for aluminum. (The common zinc-aluminum alloys also melt in the 700 degree range -- even though aluminum needs a higher temperature to melt, it's actually DISSOLVED in the zinc -- just as common table salt, with a VERY high melting temperature, DISSOLVES in room temperature water....).
This means you can melt zinc alloy over a propane flame -- like a barbecue or gas stove. Note: I would NOT recommend doing it on your kitchen stove. I've done this, but then you have to carry a 700+ degree pot of molten metal through your house and outside to where you have the mold. (If you try to pour molten zinc inside your house, you're insane -- just *melting* it inside is crazy enough.)
(2) Zinc alloys don't shrink nearly as much as aluminum -- so you can basically make a part prototype the size you want it to be, without calculating in shrinkage; and (3) Zinc alloys are nearly as strong as steel, in many respects.
WARNING -- the BIG drawback to zinc is this: THE FUMES ARE TOXIC. If you breathe a lot around melting zinc, and inhale a lot of the fumes, you're going to be very, very sick, and possibly die.
Now -- with lots of ventilation, and doing things outside, I understand it CAN be pretty safe. After all, gasoline fumes are toxic; so are toluene, turpentine, etc. -- and we're not utterly terrified of them. Just use some caution, mmmm'kay? And - read up on it a little.
One last note -- it's not the most economical source of zinc, but it's kind of fun, especially for small parts: you can simply use pennies. Since 1982, pennies are mostly just zinc. Look at http://www.gizmology.net/stovetop.htm for more information. Seems to me it's about 2x as expensive as what I can buy scrap Zamak for, around here, but sometimes for small parts it's just easier.
That's all for now -- on to making the lathe!
First of all, there's an excellent Yahoo! group devoted just to the Gingery books, machines, etc. You should definitely check out the Lindsay books (see link in step #1), and the Yahoo group: http://groups.yahoo.com/group/gingery_machines/.
There's a TON of good information and suggestions on the group. Some of the more popular ones seem to be: make the ways (a slab of 1/4" x 3" cold-rolled steel, on which the carriage (the main cutting-tool holder assembly) rides) thicker and thus sturdier; secure the ways to the bed with many more fasteners; and use a modified tool-post/toolholder. There are designs, photos, corrections, bills of materials, etc. (I'll try to add much of that information here, as I'm able.)
Secondly - the Gingery method mostly assumes using scrap aluminum. A few things I've learned:
(A) "Can you use beer/soda cans?" This is often referred to as "beercanium", or some similar funny term. The concensus I've seen, and have experimentally verified, is this: you can't really use JUST beer cans -- aluminum exposed to air instantly develops a thin layer of aluminum oxide (for fun, this is also. in crystalline form, basically ruby!). Beer cans are thin, with lots of surface area, so melting beer/soda cans alone just doesn't really work well (especially since melting tends to produce MORE oxidation.
HOWEVER -- if you melt some aluminum, such as window frames, pistons, etc. -- and THEN drop in some well-crushed and dried beer/soda cans, they'll contribute to the mix just fine.
SAFETY NOTE: if there's ANY moisture left in the cans, you are probably going to witness a SPECTACULAR explosion several milliseconds before losing your vision permanently. I'm not an expert, and if you follow my instructions, you'll probably DIE, be seriously maimed, or end up on some very, very pernicious mailing lists -- do NOT take ANYthing I say as anything other than potentially *very* dangerous activities. YOU HAVE BEEN WARNED.
(B) Using Metals Other Than Aluminum -- this is my personal choice. I cast a few parts out of Aluminum, then switched to a Zinc-Aluminum alloy (called Zamak, among other things).
Why?
Several reasons. (1) Zinc melts at MUCH lower temperatures, in the 700-degree range vs. 1,400 degrees for aluminum. (The common zinc-aluminum alloys also melt in the 700 degree range -- even though aluminum needs a higher temperature to melt, it's actually DISSOLVED in the zinc -- just as common table salt, with a VERY high melting temperature, DISSOLVES in room temperature water....).
This means you can melt zinc alloy over a propane flame -- like a barbecue or gas stove. Note: I would NOT recommend doing it on your kitchen stove. I've done this, but then you have to carry a 700+ degree pot of molten metal through your house and outside to where you have the mold. (If you try to pour molten zinc inside your house, you're insane -- just *melting* it inside is crazy enough.)
(2) Zinc alloys don't shrink nearly as much as aluminum -- so you can basically make a part prototype the size you want it to be, without calculating in shrinkage; and (3) Zinc alloys are nearly as strong as steel, in many respects.
WARNING -- the BIG drawback to zinc is this: THE FUMES ARE TOXIC. If you breathe a lot around melting zinc, and inhale a lot of the fumes, you're going to be very, very sick, and possibly die.
Now -- with lots of ventilation, and doing things outside, I understand it CAN be pretty safe. After all, gasoline fumes are toxic; so are toluene, turpentine, etc. -- and we're not utterly terrified of them. Just use some caution, mmmm'kay? And - read up on it a little.
One last note -- it's not the most economical source of zinc, but it's kind of fun, especially for small parts: you can simply use pennies. Since 1982, pennies are mostly just zinc. Look at http://www.gizmology.net/stovetop.htm for more information. Seems to me it's about 2x as expensive as what I can buy scrap Zamak for, around here, but sometimes for small parts it's just easier.
That's all for now -- on to making the lathe!
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long story short, it won't kill you, but save yourself a few days in bed and go buy a proper respirator. (not a dusk mask. there's a difference)
"Illness" *can* be defined broadly enough to encompass just feeling bad physically, but generally if you say "Dave was in the hospital with an illness", most people will assume he had a disease. (An infectious agent (bacterial or viral); cancer; some manifestation of a disorder (like, say, MS, or sickle-cell anemia), etc.) One would NOT, given the word "illness", assume that he had ingested Drano, or breathed a lot of H2S, or overdosed on valproic acid.
If you get a free exciting ride in a boxy trucklike vehicle with flashy lights and a siren, because you accidentally poured insecticide on your Wheaties, that's poisoning, not illness. Ditto if you're a plumber and melt (and breathe) way too much lead. And...ditto if you melt a bunch of zinc and breathe it. You've ingested a substance that's bad for you and causes negative symptoms -- that's poisoning.
Again - that's nitpicking over terms. But the *crucial* thing is: that I'm right and you're wrong. >;-)
Movin' on: you make a decent point that it (probably) won't kill you, but from what I've heard, you might *want* to die -- it apparently feels like a serious case of flu: fever, chills, nausea, headache, fatigue, muscle aches, and joint pain. (Check out "Metal Fume Fever" on Wikipedia.)
You're totally right that a respirator is a way different thing than a 'dusk' mask (sorry, I *do* know it was just a typo - just couldn't resist ;-), and far more appropriate in this situation. However, I'd recommend not relying on that either - ventilation is in turn far more effective than a respirator. (Note that chemists generally don't wear respirators; they use laminar-flow fume hoods -- as I do. ;-) And when you're melting a few lbs of metal at 700C, as a hobbyist -- frankly, I can't see doing it indoors anyway (even if you *don't* have a wife to help you understand all the ways in which you've screwed up) -- you wouldn't build a campfire in your basement or garage, right? You do it outdoors -- AND YOU STAND UPWIND. If there's yellowish-green smoke coming off it -- pretty likely -- be on the other side. If you can smell it (and it's not horrible, but it's distinctive, like smoking a roll of pennies), you're breathing it.
Don't. (Just trust me on this one.)
Milk won't help.
a) It wasn't my suggestion (that came from "SirDave"), but I thought I'd look into it and respond.
b) I read the link you mentioned. Lots of reasons to not breathe lots of zinc fumes, but nothing about milk. (And there was a lot of MIXED info there; e.g. ZnCl poisoning mixed with ZnO, + lead, cadmium, etc.)
c) OT1H, breathing loads of concentrated Zn fumes is Real Bad and will kill you, no matter what you drink. OTOH, as with lots of folk wisdom, there's often some truth to it.
And here's why I immediately thought this one might be "true": I work with chemicals, including glass labware, which means I'm familiar with HF - hydrofluoric acid -- one of the scariest damn things you can find in a chem lab. It's like the inorganic equivalent of anthrax, plus ebola, imho.
Funny thing is - it's technically not even a 'strong' acid, like hydrochloric or nitric or sulfuric - it just happens to do 2 things: (1) unlike those acids, it WILL eat glass (Breaking Bad had a plot point based on this!); and (2) fluorine, being the most electronegative element, wants to replace all other anions - including calcium. Which your bones are kind of made out of. SO: when you spill HF on your skin, nothing much happens. It doesn't hurt, your skin doesn't burn or smoke, you may not even notice. Until it sinks down to the bone and starts dissolving it, by which time it's usually too late -- and the pain is apparently rather spectacular.
Here's the deal, though: people who work with HF keep a supply of CALCIUM GLUCONATE cream around, to rub on the skin at the site of any spill (just before calling 911 and taking an ambulance to the ER, which is mandatory at many/most university chem labs). The calcium provides a sort of 'decoy' for the HF to bond with - it's highly electropositive, and thus forms calcium fluoride, or "fluorspar" - a common mineral that's so insoluble as to be essentially harmless. (Unless it's formed from HF + your bones.)
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Somewhat similarly, calcium interferes with zinc absorption in the body - this is pretty well documented (see, e.g. www.ajcn.org/content/65/6/1803.short).
Personally, I'd go with a massive calcium supplement from the pharma counter (like crushed oyster shells) rather than milk -- but this here pseudo- episode of Mythbusters ends with the conclusion: Milk WILL in fact help. (How much is an issue, but it WILL at least help somewhat.)
HOWEVER...
Don't mess with zinc poisoning. Remember the rule of 1* - because that's exactly what you have. (translations will be left to the reader.)
I'm still really heavily slanted towards PREVENTION as a strategy. If you start to feel like you have the flu, from melting zinc (etc.) -- YOU'VE PROBABLY DONE SOMETHING WRONG (and something which was easily preventable).
This is simple - but requires the difficult step of THOUGHT (and planning):
1) Ventilation is your very best friend. (Ummm...after safety glasses. And your brain.)
2) Breathing fumes from molten metal is probably going to shorten your life -- so don't do it.
3) ALWAYS ask yourself: "what's the WORST that could happen?" Then plan to avoid that. And what you're going to do if it happens anyway.
Have an "escape plan":
What if you trip? What if your crucible breaks? What if your tongs break? (mine did, once!) What if you get stung by a bee -- and drop a crucible full of molten metal near your feet? What if the phone rings? What if your kid runs out the door and tries to hug you? (Kids do that.) What if your grip on the crucible starts to slip -- do you have an "emergency-dump sand-bed" nearby? (Hint: do NOT dump molten aluminum on concrete!)
What if you DO get a severe burn -- do you have ANY plan for that? Do you have a "buddy" nearby, who can at least call 911 and/or pile you into the car and head for a burn center? Do you KNOW where the nearest burn center, or even just hospital, is?
Yep - that's overkill. Until you need it. >;-)
"Luck is the residue of careful planning." -- paraphrase from some important dead white guy
Read up on Zinc poisoning people - Any heavy metal poisoning is bad news.
It can affect your health years after it occurs.