Bouncing mills and other scary stuff....

Discussion in 'Mistakes, Blunders and Boo Boos' started by MrMetric, Feb 23, 2019.

Help Support HMEM by donating:

  1. Feb 23, 2019 #1

    MrMetric

    MrMetric

    MrMetric

    Well-Known Member

    Joined:
    May 16, 2011
    Messages:
    54
    Likes Received:
    6
    Gender:
    Male
    Location:
    Tranquility Base, Moon
    I grew up in a die casting and machine shop and I've seen, or heard of, some nasty stuff. Here a few, as well as some of my own experiences:
    • Never put a can of chili next to a crucible of molten metal! The guys used to warm their chili by placing it next to the gas fired crucible. In came a new guy who decided it was a good idea. Unfortunately, he didn't notice others poked holes in the top of the can. Yep! The can exploded and went straight up. It came down in the crucible full of about 700 pounds of molten aluminum. That is kind of like adding H2O to concentrated H2SO4. Instant explosion! Fortunately nobody was hit by the volcano.
    • Always wear your safety glasses in the shop! One guy saved his eyesight while walking to the bathroom because the milling cutter that broke 40 feet away hit his glasses, not his eyeball.
    • Have an overflow for those crucibles when they break. Fortunately, this was already there. But molten metal on concrete is a bad combination. Concrete has a lot of water in it that will instantly boil, which then explodes the concrete (and the molten metal on top of it). A specialized trough solves that problem.
    • Don't max out your forklift... Bad things happen when you start to top forward because your stuff is too heavy. *NOTHING* will stop it so just hang on for the ride because it is going to be nasty. I've seen the back end drop heavily about a foot (broke the lift) once the item slid off the forks.
    Now my own:
    • Walk behind forklifts are dangerous. When I was 15 I was going faster than I should have (stupid). Thank goodness for that operable safety brake when the steering lever was raised. I wasn't injured through crushing.
    • Always look *UP* when driving a forklift. We had a low doorway between two buildings and way too much stuff around to monitor while moving a machine (sling). Jockeying the lift back and forth, I hit the header and was presented with some concrete blocks being partially dislodged. Ironically, the same thing had happened about 6 weeks before. Moral of the story? One person does something, shame on them. Two people, shame on you.
    • This one didn't bite me but... A-frame lifts on wheels are dangerous when trying to right dies laying flat; unless you constantly move the frame so the chain is vertical, at some point the frame on wheels will slide over, too far actually, and then the now descending weight below and absurdly out of plumb chain will 'pull' the frame down. I saw someone do that; he is lucky it didn't kill him. Instead, the lift toppled "around" him, although I suspect he needed to use the rest room afterwards (btw, no hard hat). That was probably one of the scariest things I've seen
    • Now for the home shop guys.... We are poor so we move our own machines with half baked equipment. Liftgate trucks are almost always a bad idea. You cannot crack open the valve to lower the gate. Due to the weight, the gate will come down alarmingly fast so you'll release the switch, which will shut the hydraulic valve off so quickly that the lift will start to bounce. That nice mill will be metal on metal and it could bounce off the gate. Moral of the story? Two really. First, don't use liftgate trucks. Two, and something you should always do... Position yourself in a location where you can't do any heroics. That split second 'emotional' response of "oh, %#$%*@, my expensive baby is going to break" simply doesn't matter because you are unable to put yourself in harm's way.
    • Which, reference above, is why I always use a suitable forklift. When you are in the driver's seat, you basically have no choice but to sit and watch... no heroics.
    • And now my really bad one... I was checking out a machine to buy. The guy had it wired incorrectly and when I turned it on, the chuck started to spin off. I always stand to the side and my instant thought was, "oh <removed>, thank goodness I'm over here!" Then that emotional "Oh <double removed>, this isn't my machine!" came in and for God knows what reason, I did something no sane person would ever do.... I tried to catch the chuck as it fell onto the bed of the lathe. *THAT* is the power of emotion. It kicks in when logic says run as fast as you can. Fortunately, all my digits are still here but I did have a good trip to the ER for stitches and I still have a scar. I look at that often just so I remember how powerful emotion can be.
    That's a lot of 'stuff'. I hope I didn't bore you. The last one, my own, was one of the best lessons in my life because it taught me that no matter how old you are, the best way to avoid an accident is to ensure you aren't ever in a position where you can let emotion kick in. Frankly, it is impossible to do all the time, but it is the reason I usually try to set myself up for success. I plan. I put safety equipment where it is available (extinguishers, bandages, phone, etc). I try to make sure someone is around when I am doing something more dangerous. And I use appropriate equipment (like a forklift instead of that really scary engine hoist), and I avoid liftgate trucks whenever possible.
     
    Last edited: Feb 23, 2019
  2. Feb 23, 2019 #2

    MrMetric

    MrMetric

    MrMetric

    Well-Known Member

    Joined:
    May 16, 2011
    Messages:
    54
    Likes Received:
    6
    Gender:
    Male
    Location:
    Tranquility Base, Moon
    Should you be wondering about OSHA (a US agency charged with workplace safety), most of this stuff occurred about 40 years ago. Things were different then. But home shop people don't have OSHA looking over their shoulders so they may possibly be performing similar actions today, hence the reason I brought up the cases. Be smart, be safe.

    Funny thing about OSHA... I was having a new roof installed a few years ago and I was watching these guys charge all over my rafters when the supplies were delivered. When they finished, they all donned harnesses and posed for a picture or two. I asked the foreman about it and he told me that OSHA required harnesses be used and that was their "proof" they had used them. Hmmm.
     
    Dubi likes this.
  3. Feb 23, 2019 #3

    larryg

    larryg

    larryg

    Well-Known Member

    Joined:
    Mar 24, 2015
    Messages:
    55
    Likes Received:
    23
    Gender:
    Male
    Occupation:
    Retired Maintenance tech now Farmer
    Location:
    Oregon, USA
    It has taken me a lot of years to train my self to just stand back and enjoy the crash. As a young man I would try to catch or stop something falling, no more.

    lg
    no neat sig line
     
  4. Feb 23, 2019 #4

    MrMetric

    MrMetric

    MrMetric

    Well-Known Member

    Joined:
    May 16, 2011
    Messages:
    54
    Likes Received:
    6
    Gender:
    Male
    Location:
    Tranquility Base, Moon
    I'm sure your insurance company appreciates your training. :)
     
  5. Feb 24, 2019 #5

    Cogsy

    Cogsy

    Cogsy

    Well-Known Member Staff Member Global Moderator

    Joined:
    Jul 30, 2012
    Messages:
    2,584
    Likes Received:
    742
    Gender:
    Male
    Location:
    Perth, Western Australia
    You raise some good points, especially about 'heroic' saves (I'm guilty of that myself - curse my cat-like reflexes). The chilli story does sound like a bit of an urban myth though. Moisture trapped under molten metal is an incredibly bad thing and the resulting explosion is terrifying to say the least (I've seen my share) but dumping moisture on top of the metal results in an instant cloud of vapor and very little else. The burnt chilli would have mad the shop smell nice for a while though.
     
  6. Feb 24, 2019 #6

    MrMetric

    MrMetric

    MrMetric

    Well-Known Member

    Joined:
    May 16, 2011
    Messages:
    54
    Likes Received:
    6
    Gender:
    Male
    Location:
    Tranquility Base, Moon
    The whole can ended up in the crucible and it blew stuff all over... beans, metal, etc. That wasn't, believe it or not, an urban myth because I actually saw the results. I didn't see the actual event, but I heard the bang and the mess. I understand what you are saying about it not making sense, but that is how it played out. Maybe if it happened again, it would just boil off, I don't know. I'm not sure I would want to try it though.

    I should also qualify this with... At the time, I was 15 or 16. That was decades ago. I remember being scared by the whole thing, but maybe it was a case of the "I once caught a fish that was T-H-I-S big...." I don't think so, but memories can play tricks on you.

    I do have a strong interest in sand casting now, but I don't have the space; I also have fears of the EPA coming down on me. But, my experience around molten metal has given me a healthy respect for it. I'm actually kind of scared of the stuff.
     
    Last edited: Feb 24, 2019
  7. Feb 24, 2019 #7

    davidyat

    davidyat

    davidyat

    Well-Known Member HMEM Lifetime Supporter

    Joined:
    Dec 29, 2012
    Messages:
    179
    Likes Received:
    38
    Gender:
    Male
    Occupation:
    Retired/Self Taught Machinist
    Location:
    Indianapolis, Indiana
    My story is learning when something drops, slips out of your hand or is falling off the work bench, don't try to catch it. How many times did I try to catch something and didn't quite catch it, only flinging it farther and making matters worse or damaging the item worse. Now that I've trained myself, when something slips, I just freeze. Let it go. Hopefully it's not a part you've put a lot of work into and you can always make another one. Obviously when it's big stuff, I get out of the way.
    Grasshopper
     
    happy hooligan likes this.
  8. Feb 24, 2019 #8

    a41capt

    a41capt

    a41capt

    Well-Known Member

    Joined:
    Jun 6, 2009
    Messages:
    94
    Likes Received:
    33
    Gender:
    Male
    Occupation:
    Retired Firefighter
    Location:
    Camp Verde, Arizona USA
    I concur. As a bullet caster, I know better, but my mind must’ve been elsewhere (a DANGEROUS condition when working with any molten metal) when I unthinkingly added a handful of poorly cast bullets back into my lead pot. Oh, did I mention that I always chill my bullets coming out of the mold in a 5 gallon pail of water?

    While I didn’t inject the wet bullet under the molten lead as suggested regarding subsurface water, the resulting steam explosion shot molten lead 7 feet into the air (I know this is how high it went because my ceiling still has the lead splatter present) and also onto my arm and hand. I had, however, taken the necessary safety precautions of a long sleeved shirt and gloves which saved my hide, but my wife still berates me for my stupidity every time she sees that shiny spot of ceiling...
     
  9. Feb 25, 2019 #9

    oldchadders

    oldchadders

    oldchadders

    Active Member HMEM Supporter

    Joined:
    Aug 13, 2013
    Messages:
    29
    Likes Received:
    2
     
  10. Feb 25, 2019 #10

    oldchadders

    oldchadders

    oldchadders

    Active Member HMEM Supporter

    Joined:
    Aug 13, 2013
    Messages:
    29
    Likes Received:
    2
    I had a science teacher many years ago who had a great gift of using "things that happen" to teach a lesson. One day he appeared with his lower right arm heavily bandaged. He explained that he had been helping his wife doing the washing up and dropped a carving knife, which he then tried to catch, badly cutting his wrist. Prompting for a motto for the story, most of the boys suggested "not to help with the washing up" but I suspect that most of us learned the real lesson - you don't get many teachers like that nowadays!!
     
  11. Feb 25, 2019 #11

    davidyat

    davidyat

    davidyat

    Well-Known Member HMEM Lifetime Supporter

    Joined:
    Dec 29, 2012
    Messages:
    179
    Likes Received:
    38
    Gender:
    Male
    Occupation:
    Retired/Self Taught Machinist
    Location:
    Indianapolis, Indiana
    Oddchadders,
    Just what I learned! OH, and when you did try to catch the dropped object, how many times did you slap it to a location where it took over an hour just to find it!!!
    Grasshopper
     
  12. Feb 25, 2019 #12

    Cogsy

    Cogsy

    Cogsy

    Well-Known Member Staff Member Global Moderator

    Joined:
    Jul 30, 2012
    Messages:
    2,584
    Likes Received:
    742
    Gender:
    Male
    Location:
    Perth, Western Australia
    Your cast bullets, being solid, would have been denser than the molten lead and would have submerged, with the added problem of being somewhat porous and holding liquid water in them. So you did place the water under the surface of the molten metal and this is indeed extremely dangerous. With water expanding around 1600 times its volume upon changing to steam, the explosion displaces a huge amount of metal. I've personally seen several such explosions in my time as a hot dip galvaniser (and the horrific injuries that often result) and you never want to be anywhere near such a thing.

    With the chilli, I know an exploding can makes an enormous bang on its own and the physical impact of the can and contents hitting the metal may have splashed a little, but being far less dense than the metal, and substantially less volume, the Leidenfrost effect pretty well ensures you don't get a steam explosion in such circumstances. It's also why we don't have to worry about sweat from our brow dripping into the melt when we're casting - it just flashes off with no harm done. With chilli flying everywhere and a big noise I can understand the confusion though.

    I found a video on Youtube that shows what I'm talking about - about half way through he pours water onto the molten metal (for his first test with water in the mould he was incredibly lucky it didn't go bad).

     
  13. Feb 25, 2019 #13

    a41capt

    a41capt

    a41capt

    Well-Known Member

    Joined:
    Jun 6, 2009
    Messages:
    94
    Likes Received:
    33
    Gender:
    Male
    Occupation:
    Retired Firefighter
    Location:
    Camp Verde, Arizona USA
    Thanks for the explanation, you live, you learn, you grow! I do know I learned one thing from my event, NEVER put any water into ANYTHING that you don’t want steam to come out of!

    As a 42 year career firefighter and HazMat Technician/Specialist, I knew these rules ahead of time, but was shown the full-on demonstration with my own foolish inattention!
     
  14. Feb 26, 2019 #14

    Dubi

    Dubi

    Dubi

    Active Member

    Joined:
    Jan 9, 2018
    Messages:
    31
    Likes Received:
    5
    Gender:
    Male
    Occupation:
    Designer of Wet Submersibles
    Location:
    Indonesia
    I recall some years ago melting aluminium in a ceramic flask. I started to smell burning rubber and looked down to see I was standing in a molten flow of aluminium. Never moved so fast in my life. Will never use ceramic flasks anymore only cast iron.
     
  15. Feb 27, 2019 #15

    MrMetric

    MrMetric

    MrMetric

    Well-Known Member

    Joined:
    May 16, 2011
    Messages:
    54
    Likes Received:
    6
    Gender:
    Male
    Location:
    Tranquility Base, Moon
    I'm very interested in casting, but I don't really live in an environment where I could do it easily. I'm pretty sure that the fire department, air quality board, FBI, CIA, and Homeland would all pop up on my door the moment there was any off-smoke that looked nasty. :( Maybe when I move away from here during retirement. Anyhow, casting is very cool but when I look at the videos, I always feel like people are a little cavalier about the clothing and safety equipment they have on. I don't know the recommended equipment as I am no expert on the subject, but it is just my impression.... But, funny story. I bet you did move fast!
     
  16. Feb 27, 2019 #16

    Eric C

    Eric C

    Eric C

    New Member

    Joined:
    Dec 21, 2018
    Messages:
    1
    Likes Received:
    0
    Gender:
    Male
    Location:
    Bay Area, CA
    Hi MrMetric. Where in Sunnyvale? I live in Sunnyvale too. There are a couple of blacksmiths around here. One of them in the San Miguel neighborhood uses bituminous coal, and the neighbors are cool with it. It probably depends on the location. I am trying to set up a foundry.

    My silly foundry story is that once I was working under the direction of an experienced foundry master. I was doing my first brass pour, and we were working over a steel plate floor. The brass was dirty, so it was a bit overheated, and when I bobbled the full crucible, the flux cover opened a little and the top ignited releasing a huge plume of zinc smoke which caught me in the face and made me gag. The foundry master laughed and said pour pour like you're supposed to. Anyway, I got an inclusion due to being nervous, and the foundry master came over afterwards and asked why I was so squeamish about breathing a little zinc fume. Too much internet surfing? He told me that I must be reading horror stories on the Internet. The room was all set up with a commercial furnace, and a ventilation hood. When I came later, he laughed again and asked, didja get sick, didn't think so.
     

Share This Page