NEW THOUGHT - Am I nuts - calling a chemist

[anwalt]

I have a building with a galvanized roof that was showing rust.  To my local big box I traveled to purchase aluminized roof coating. 

I asked the clerk to shake the can to mix the contents.  The clerk responded that the can was likely to explode if he shook it on the paint shaker. 

I mildly challenged the clerk as to how it could explode, but as it was his shaker I took my coating and quietly went on my way. 

I agree that finely divided aluminum is reactive.  However, (1)  as the can is closed, no oxygen is accessible to the aluminum and (2) every aluminum particle in the can is coated with asphalt or the oil carrier, or both, hence even if  O2 were present the aluminum is shielded from the O2. 

Am I nuts or is the clerk? 

tom

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10/11/2016

On further thought, I think Mad-Planter, Black Hat, & Wild Turkey are correct.  The solids reached about 1/2way up the can.  Since I stirred the contents by hand and with an electric drill I can say the solids were well consolidated.  If a significant part of this cylinder of solids were to hammer the can as the can shakes, the can may burst. 

From the vendor's perspective it is better to refuse to shake the can than used a stronger can. 

The clerk used the work 'explode'.  I immediately thought of a chemical explosion rather than a mechanical failure of the can. 

Thanks for setting me straight. 

tom

[Mr_Mike]

Clerk is a person. Or whoever made that policy is.

[mad_planter]

If you google that it appears that there are numerous hits that mention not shaking it (even manufacturers).   It appears to be more of a popping the lid off making a mess than a actual reactive explosion.

[blackhat]

Perhaps its a new formula with nitroglycerine as a binder.  Or perhaps its a weak can that can't take being clamped in the shaker.

[EricU]

the instructions don't tell you to shake it?  That would be great, I used something recently where shaking it forever was part of the instructions.

[Herb G]

Or perhaps its a weak can that can't take being clamped in the shaker.

This is most likely the correct diagnosis. I bought a can of paint not long ago that didn't make it to my car before the bottom fell out. I left a streak all the way across the parking lot.
Most of the cans on the shelf were like that one too.

[Wild Turkey]

I suspect it's the mass of the asphalt carrier that they're worried about.  Get it moving as a slug and it could hit the lid with a lot of energy.

[tomsteve]

most people I know that question if theyre nuts usually go to a psychologist or psychiatrist.


but then again, im just on a week long vacation from forrest view.

[Woodenfish]

The friction of the material most likely builds heat and pressurizes the can while in the rapid oscillating mixing machine. Very possible that it could over pressurize and blow the lid off leaving him to clean it up. I don't blame him for his logic.