Re: A Handy Tip For Gorrilla Glue Users

No problem.

Reply to
J. Clarke
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If you have to go out and find you're all out of acetone, try some morticians makeup. It hides those spots really well.

Reply to
mp

Depends on how you're trying to set fire to it. Flashpoint is widely misunderstood (actually it's very rarely understood at all). Think of it not as "the temperature at which it _will_ ignite" but rather as "the temperature at which it _can_ ignite". Formally it's the temperature above which a flammable liquid gives off enough vapour to form a flammable atmosphere. You still need to supply an ignition source.

Most materials have flashpoints well above room temperature. The ones we think of as flammable are those where the flashpoint is at some temperature that's easily achieved - room temperature or thereabouts. In practice this means that a spill of it forms a flammable atmosphere and just needs a spark to light it. A liquid with low flammability would have to be heated before you could even begin to try igniting it (of course a flame or heat source might achieve both simultaneously).

Strictly speaking, "flammable" (in some countries) is for a flashpoint of between 23-61°C ("room temperature" is about 23°C) and "highly flammable" is a flashpoint below this. AFAIR, in the USA these definitions are different and it's 100°F that's the break for "flammable"

Some other aspects of "risk of fire" are the minimum energy needed to cause ignition (this is why we can easily demonstrate that static discharges won't cause dust collector fires) and also the range of mixtures (fuel/oxygen ratio) which form a flammable mixture. This is the reason why gasoline is so hazardous - almost any proportion is an explosive mixture.

In the case of cyclohexane vs. acetone, they both have similarly low flashpoints (-20°C and -18°C) but the autoignition temperature of cyclohexane is only 2/3rd that of acetone (260°C vs. 538°C). With the vapour around (and this is almost inevitable) then a much lower energy of spark is needed to ignite cyclohexane than acetone.

A useful handy resource with the numbers:

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Reply to
Andy Dingley

Interesting.

Reply to
mp

Andy Dingley wrote in news: snipped-for-privacy@4ax.com:

I've never used cyclohexane (although I was a chemical engineer as one of my past jobs).

They are both "darned flammable." Both have flashpoints around -20C, and lower explosive limits of only a couple percent in air (e.g., about like hydrogen). Cyclohexane's got about half the lower explosive limit of acetone, but acetone's got a higher vapor pressure and evaporates faster. Both are denser than air, so the vapor will concentrate along the floor.

I'm not at all saying that acetone can't be used reasonably in the home shop; I use it, too. But people ought to watch out for ignition sources and ventilation. It is a worse flammability hazard than more usual solvents like mineral spirits and ethanol.

Reply to
Nate Perkins

Dave Hinz wrote in news: snipped-for-privacy@individual.net:

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at the entries for flash point, flammability limit (lel), vapor pressure, evaporation rate, and vapor density.

Reply to
Nate Perkins

Thu, Mar 10, 2005, 5:42pm (EST+5) snipped-for-privacy@a.com (stoutman) claims: Than Im in deep shit. We use acetone to wash our glasswear at work. I have been getting it on my hands for over 10 years with no problems. That beer you drink at night is worse for your liver than a little acetone on your hand.

Duuno, but my dad used to work with a guy who rinsed the grease off his hands with some type of chemical cleaner on a daily basis. He was told it wasn't a good idea, but did it anyway. Then all of a sudden his hands just kinda wrinkled up, and went all white. Never did hear the final outcome.

With Titebond water cleanup works. Cool.

JOAT Intellectual brilliance is no guarantee against being dead wrong.

- David Fasold

Reply to
J T

Any degreaser is bad new on your hands - humans are just made out of too much grease. Anything that cleans them is also degreasing the skin. There's a reason why my workshops always have barrier cream and handcream to hand. (These days it's tradefair shea butter stuff - much nicer than Nivea or Oil of Oily)

He was lucky. Most of the workshop solvents that really are harmful cause liver damage. Very nasty way to go 8-(

If the skin went white, might it have been hydrogen peroxide he was splashing about ?

Reply to
Andy Dingley

Mon, Mar 14, 2005, 12:09am (EST+5) snipped-for-privacy@codesmiths.com (Andy=A0Dingley) wonders: If the skin went white, might it have been hydrogen peroxide he was splashing about ?

Nope, a 55 gallon drum of some chemical they dipped tools in, on a wire, to degrease them. Something like carb cleaner, apparently. That guy was the only one that wanted it on his skin. The rest of 'em, if it splashed on their hands, they went and washed with soap and water. Strictly for degreasing/cleaning metal.

JOAT Intellectual brilliance is no guarantee against being dead wrong.

- David Fasold

Reply to
J T

Could have been 1-1-1-tricholoroethylene, although it's more effective as a vapor degreaser. And I wouldn't want it on my hands.

todd

Reply to
Todd Fatheree

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