View Full Version : Scrap bin warning

03-05-2017, 08:21 AM
I had a job which needed a heavy plate to mount a tube bender. Off to the scrap bin and picked up this 1" X 8" X 8",it was a dull gray color, looked like aluminum but was much lighter. I though this aluminum plate is really light and looks to be hardened. On the plate there was a manufacturer stamp " tool plate" and some illegible sharpie marker writing (esium or ebiun )???. To me the material I was using didn't really matter it was just a base plate to mount the bender, so off to the milling machine to square it off and drill the mounting holes. After I was all done machining, the plate was sitting on the bench, my co-worker came by for a chat and we talk about the plate being so light and he mentioned could it be Magnesium? I then realize, yes, that make a whole lot sense, dull grey, easy to machine and extremely light. I took one of the shavings and lit it with the torch and it burn bright white just like magnesium. I am glad my tooling was sharp and didn't linger over while cutting this stuff. Then that got me thinking, what other metals I should be careful of? Beryllium is another one that comes to mind. Because most of my homeshop metal stock comes from the dumpster bins, I usually call this material scraptanium, freetanium or obtainium .

03-05-2017, 09:22 AM
You are very lucky. You cannot extinguish a metal fire with the usual fire extinguishers or water. It requires a class D extinguisher. I have a halon extinguisher for that purpose but good luck trying to find one of those.

03-05-2017, 11:46 AM
8x8x1 magnesium? lol.. lot of energy can come from that when burning!

Are you sure it's not just AlMag - high mag content aluminum alloy? lots of that around here. Machines well, but hard to start a fire from just that.. Oh.. it will burn spectacularly - throw an old VW motor or Pro stihl chainsaw into a fire ;)

03-05-2017, 11:55 AM
Titanium has almost all the same traits too.

03-05-2017, 12:51 PM
If it really was magnesium or Ti you could probably sell that block and get a lot more aluminum or steel to replace it. ��

03-05-2017, 01:28 PM
That could be dangerous, but could you get a large piece hot enough with a dull end mill???? It takes a fair amount of heat to start it.
I would think a large piece would dissipate the heat faster than a dull end mill could heat it up.

I remember when I was in high school we had magnesium tape in the science lab. It came in short strips about 3" long x 1/8" wide. Looked just like a bread tie.
One day in the auditorium I decided to take a Bic lighter to it, it lit the whole auditorium up like it was daylight. Got a nice vacation for that.


03-05-2017, 01:40 PM
When I was teaching Metal Shop we were short of Aluminum for the melt furnace. One of the students brought in a rotary lawn mower deck. We chopped it up into small pieces and loaded the crucible. With all that was going on, somebody wasn't watching the furnace and the "Aluminum" lit off. It burned for the rest of the class and a bit of the next period. It was like a huge "Highway Flare" and I got to reline the furnace.

03-05-2017, 01:49 PM
This happened sometime late last century.

Back when the missile factories around Tucson were producing lots of nice light air frames there was a recycling company who took in the waste for reprocessing. At some point he had 100's of 55 gallon drums of magnesium and titanium scrap sitting on the desert. Somehow it caught fire. We lived about 40 miles north of the facility but we could easily see the glow covering 1/4 of the night sky. When it was done burning they found that the burning metals had turned the top layer of the sand into a glassy slag.

03-05-2017, 01:55 PM
My sons were in scouts so at a campout we showed them metal burns by tossing a VW engine case in the hot coals. Once I had an out of date second chanz rocket propelled ultralight chute we strapped to a tree & pulled the cord & yep it still worked. The dads had more fun than the kids I think.

03-05-2017, 02:16 PM
That could be dangerous, but could you get a large piece hot enough with a dull end mill?

It's the chips that are easy to start. Then if one gets in with others that can start the entire pile and away it goes. When I worked at Northwest Industries they would sometimes be doing CNC machining of large pieces of magnesium for aircraft. When that was happening there would be a large no-go zone anywhere near the machine. Even just skidding a small chip under a boot could start one up.

03-05-2017, 02:21 PM
We had thermite in high school chemistry to fool with, outside of course.

Do they still use it in schools or is it considered too dangerous?

03-05-2017, 03:00 PM
This is one of the areas that really upsets me. In science classes everything is now done by simulation on a computer instead of the real thing. Watching a computer simulation does NOT give a good insight into reality. When my father taught science he had a room in the back with the elements A to Z and a lot of other chemicals as well. We even did experiments using radioactive tracers in plants. Try that today!

03-05-2017, 03:05 PM
Back when it was still ok to hit students in school, one of my science teachers put I think it was a small piece of Sodium in a beaker with some water, then put a lid on it. IIRC, the sodium reacted with the water, producing hydrogen and a lot of heat, causing a small explosion, launching the glass lid off the ceiling and landing on a students desk.

Good times...well, except for getting the strap.

03-05-2017, 03:06 PM
Magnesium fire starter:




03-05-2017, 05:19 PM
@Evan, I did a similar thing when I was a kid. The summer between 8th grade and high school, I took a summer course where we ordered a variety of radioactive tracers and added each one to a different fish tank with several frogs. We dissected the frogs, dissolved the organs in nitric acid, put them in planchets, evaporated to dryness and counted the radiation coming off the different organs to see where each tracer went. This was 1968.

Can you imagine proposing this now??

03-05-2017, 06:15 PM
In my 10th grade biology class (1963) we raised tadpoles in a solution of adrenaline and observed the effects compared with a control group. That would also probably be taboo now.

There was also a program where radium rods were inserted in the noses of children in the 1950s and 1960s, in Baltimore, where I grew up.

I'm not sure if that was done to me, but I did have my tonsils and adenoids removed around 1955, and I have had nasal and sinus problems for a long time. I had deviated septum surgery in 1999, and I think it revealed that my nasal turbinates are reversed, which seems to present as inability to clear mucus by blowing my nose, and instead I need to draw it back and expel through my mouth:



03-05-2017, 08:08 PM
holy cow, nitric acid? Why not just go the whole hog and use hydrofluoric acid while you're at it?

Ah the good old days, when real boys learned how to make BBQs by cutting propane cylinders in half. Sure, a few died, but those suckers! Gotta keep the gene pool clean!

03-05-2017, 09:14 PM
holy cow, nitric acid? Why not just go the whole hog and use hydrofluoric acid while you're at it?


I remember my father (chemical engineer) telling me about a story circulating through the chemical industry: someone was screwing around with hydrofluoric acid and put a drop on the point of a pencil - next, he accidentally transferred the drop to his finger.

Next, the tip of his finger had to be amputated.

Better living through chemistry ...

03-05-2017, 09:54 PM
He coulda licked His pencil to start writing!