The sometimes fatal cost of this hobby

[TheSidewinder]

when you say lightbulb...do you mean the flash temp for acetone vapors is so low that the hot surface of a light bulb can cause the vapors to combust?

I *believe* the anwer to this is, yes, the temperature on the surface of a typical 100-watt lightbulb is higher than the flash point of Acetone.

That's one of the reasons serious pyros equip their shops with explosion-proof fixtures with a much larger safety-dome type outer cover.

[crazyboy25]

Yeah its scary I always get a headache after working with it and once I poured some down the drain then turned on the stove to boil some water. The acetone caught on fire and the stove was 7-8 ft away! It was only a tiny fire but it was scary.

[Mumbles]

Flash point is different from auto-ignition temperature. The flash point is the temperature where said compound can self sustain a flame. The flash point of acetone is -18C (around 0F), while the auto-ignition temp is 465C (about 870F). I am unsure if a standard lightbulb is capable of producing this kind of heat, but one of those new fluorescent ones probably could. They may require less energy, but they produce a lot more heat and I believe require UV filters.

 

I was having trouble thinking of a good example of something that is commonly known as flammable that would have a flash point above room temp.

 

Obviously unleaded gasoline has a pretty low flash point (around -40F or -40C). If you pour it on the ground and put a flame to it, it will light. If you tried to do the same with diesel you would not get the same result. Well if you held the lighter there you could, but just a sweep wouldn't do it. You have to preheat the diesel to burn. Kerosene and jet fuel behave the same way.

 

Auto-ignition temp table.

http://www.engineeringtoolbox.com/fuels-ig...ures-d_171.html

[TheSidewinder]

Thanks for the CORRECT answer.

 

I thought I had read/seen/heard somewhere that a light bulb's surface was hot enough to cause auto-ignition (which I mistakenly called its flash point) for certain VOC's.

 

Could Ether be what I was thinking of? I know that's a touchy one.

 

M

[jlmemt]

That is scary!

I always thought that the flourecent bulbs were cooler. I will have to check into that a little more.

 

I can honestly say that I never would have worried about a bulb for a ignition source! The switch I had, but not the bulb.

That is a good thing to know!

 

 

Mumbles,

 

You are right on the diesel fuel, but there is another point to think about. While it's flash point is higher than gasoline, it is only around 120, IIRC. I learned that a diesel truck in an accident on a hot summer day could lose it's diesel on a hot asphalt road and it could behave just like gasoline. It is not too hard to get asphalt well above 120 on a hot day.

 

Not directly pyro related, but another way to think about it, and a little easier to understand for me at least.

 

Jason

[WarezWally]

Fluorescent bulbs are much cooler than their incandescent brothers, You can happily touch one without burning yourself.

[TheSidewinder]

I could probably fry eggs on the new *COMPACT* fluorescents.

 

Yeah, they save energy but, as I learned QUITE painfully the first time that I *ASSUMED* they'd be a lot cooler, I blistered two fingers when I grabbed one full on and tried to unscrew it, after it had been lit for an hour or so.

 

That HURT.

 

I remember it like it was yesterday, and that was 2 years ago.

 

WarezWally, yes, the older long-tube style are a hell of a lot cooler but the endcaps can give you a burn if you're not careful.

 

Asketh not how I know this.

 

M

[WarezWally]

The compact ones here are hot to touch but still much cooler than the 60W incandescent lights we have.

 

I don't see how a light bulb can start a fire though, if something has a ignition point low enough that a light bulb could ignite it then you probably shouldn't be using it inside for that matter. I don't know of any substance where having a light on could be dangerous.

[Frozentech]

In my post about acetone vapors flashing back and starting a fire ( which actually happened ) the probable source was a small high intensity desk lamp. I think those use halogen bulbs, very hot.

 

It burned out the entire shop, the pyro barely made it before bags of whistle mix and KP rice hull burst went up, in his words it was an inferno fireball that filled the entire room.

 

No, acetone should not be use indoors! At least not in the qty that we use it.

[shagaKahn]

That settles it: I'm going LED.

 

Wife has a nightrider bike lamp and in the instructions it says to keep moving and to be sure and turn off the lamp if you stop for any time because the halogen bulb becomes dangerously hot.

 

Shopping for lights for our new bathroom we came across some amazing LED's. Really wanted this one but I think it was intended for use as an indirect lightsource, like under a counter or something--but talk about a kool light, figuratively and literally:

 

http://www.efn.org/~mikemcoo/koolLEDpanel.jpg

[ST1DinOH]

the c.crane company makes a ton of very cool LED's that you guys may be interested in.

 

all sorts of other nifty gadgets to play with too...especially if you are into tech and/or radio toys.

 

http://www.ccrane.com/

 

enjoy.

[GalFisk]

Yeah, halogen bulbs are by their nature a lot hotter than normal incandescents, it doesn't suprise me that they can ignite flammable vapors. CCFLs are not that hot overall, but there are filaments at either end of the tube that get quite hot. I'm unsure if it's enough to cause ignition, but why take the risk.

[Dr Dudley]

I myself was almost in the same boat as Tad. I had used my small garage as my shell making area but I didn't store any made materials within the garage. I had been making stars the previous week or two and had also just made up about 25# of homemade lift charge for my shells. This was already on rice hulls so it filled up a garbage bag full.

I came into my garage to do something and stepped on a star that had errantly gotten on the floor which immediately took fire. I noticed which direction that it was pointing to and closed my eyes and ran for the door. I was no more than 10 feet from the door which was closed when the I heard the worst noise ever in my life. I was in the garage for no more that 2 to 3 seconds before I was out the door rolling on the ground trying to put out the fire that was on the back of my shirt.

The fire from the star ignited the rice hull and bp mixture which filled the garage with fire engulfing me. I sustained 3rd degree burns to both arms to the elbow. Burned of a good majority of my hair, which I had the burn unit shave me bald, burns on my back 2nd degree. They took skin grafts from my legs to fix my arms.

The garage sustained major burns but didn't explode since I wasn't playing with flash or anything like. All 100# of my stars burnt up as well as about $5000 worth of chemicals but I am still here.

This happened February 28th, 2006.

[TheSidewinder]

Thank you for sharing a story that others should take to mind when participating in this hobby. It's another sobering reminder that it can happen to anyone. All it takes is the wrong set of circumstances.

[FrankRizzo]

Yes, thank you for that. It's sobering to here of other peoples experiences with the hobby. If you remember, what was the composition of the star?

[Frozentech]

I myself was almost in the same boat as Tad. I had used my small garage as my shell making area but I didn't store any made materials within the garage. I had been making stars the previous week or two and had also just made up about 25# of homemade lift charge for my shells. This was already on rice hulls so it filled up a garbage bag full.

I came into my garage to do something and stepped on a star that had errantly gotten on the floor which immediately took fire. I noticed which direction that it was pointing to and closed my eyes and ran for the door. I was no more than 10 feet from the door which was closed when the I heard the worst noise ever in my life. I was in the garage for no more that 2 to 3 seconds before I was out the door rolling on the ground trying to put out the fire that was on the back of my shirt.

The fire from the star ignited the rice hull and bp mixture which filled the garage with fire engulfing me. I sustained 3rd degree burns to both arms to the elbow. Burned of a good majority of my hair, which I had the burn unit shave me bald, burns on my back 2nd degree. They took skin grafts from my legs to fix my arms.

The garage sustained major burns but didn't explode since I wasn't playing with flash or anything like. All 100# of my stars burnt up as well as about $5000 worth of chemicals but I am still here.

This happened February 28th, 2006.

 

Thanks for sharing that. Do you mind if I keep a copy of that post and use it in safety discussions ? I would attribute it to "an anonymous pyrotechnician".

[Swede]

Dr. Dudley, thank you for sharing that. I had severe burns once (not pyro related) and I understand what you went through.

 

This is a valuable lesson, and I DO NOT mean to belittle Dr. Dudley IN ANY WAY, but storage of 25 pounds of BP on rice in a garbage bag? Powerful/flammable/explosive comps need to be stored in something much more substantial. If you don't use a magazine, at the very least, put stuff like riced BP inside one (or more) of those HDPE buckets. For $6, you've got a 5 gallon airtight container that will withstand stray sparks, the fallout from minor pops and such in a shop, and the burning, rolling star... the star might have burned through the bucket and ignited the BP, but I think it would have given him time, much more time, to evacuate.

 

I hope you have all the medical, financial and hopefully (no) legal issues well behind you. Again, thanks, it could hapen to me or anyone, but we need to think about how we store compositions.

[FREAKYDUTCHMEN]

Mr dudley, that sounds more like a fireworks factory to me. 100# of stars and a bag full of coated ricehulls.

I'm glad you're still alive and telling this story, that makes us more cautious.

[FrankRizzo]

Mr. Dudley,

 

The newspaper article says you lit a fireworks insert and kicked it away into other explosive material?

[whitefox77]

Mr. Dudley,

 

The newspaper article says you lit a fireworks insert and kicked it away into other explosive material?

 

Which would be newspaper ease for saying he stepped on a star which ignited and rolled into a bag of lift charge.

[spitfire]

I have a pyrobuddy who always tells story's about one of his pyrofriends some years ago. He died in a terrible accident while pouring his 20 pound ballmill contents onto a large sieve, placed over a bucket. It happenend on a cold dry day, so the cause was probably static electricity sparks. He was known for his large round shells, wich he produced in dozens at a time. I didn't knew him in person, but have read a lot from him, seen pictures and footage of him building shells with friends, including my pyrobuddy. His shop was totally distroyed and he died one day after the accident from his burn injuries. leaving behind his wife and 3-year old daughter.

 

always think twice of what you are doing, never forget what you are working with.

[Swede]

Spitfire, do you have ANY idea what the contents of the mill were? If it was plain old BP, that will surely give pause. We all (me included) get a bit too comfortable with BP.

 

I count myself fortunate in that Texas winters are almost always exceptionally damp.

[spitfire]

His millingdrum was made from large PVC pipe and an screw-lid at one end. The lid being almost half the diameter of the drum. So basically, it was a giant bottle from PVC. As i recall the story correct, he used round lead media. At it's maximum load, he milled 10 kilograms BP at a time for 24 hours. That should be around 20 - 22 pounds. It was huge, i might be able to get you some pictures of his mill and shop.

All ingredients he milled where as dry as they could be. So when pooring it out on the sieve, you can imagine what quality this BP might have been. Dry and dusty on a freezing dry day.

it might have been stupid of him, nonetheless he paid the price, and his wife and daughter untill this day.

[Swede]

Hmm, I can see that. Mill dust forming a small but dense cloud, a static spark...

 

Some thoughts: On a cold winter day, it might pay to dampen BP in a mill jar, and respect static as if you were working with FP. Use grounding straps, spray, and a mat. Rather than dumping the mill jar over a screen, scoop it out gently to keep dust down.

 

Or better yet, make your BP only when the conditions are acceptable, humidity is up.

 

A cheap relative humidity meter can be had for very little money, and it might be a good addition to a workshop, with a warning, "Thou shalt not risk anything sensitive to static when the RH is below 40%."

[Mumbles]

I've seen figures that said that BP was more sensitive to static when damp actually. I'll see if I can find the source of that.