Meths chimney burners: drinks can paint fumes?

> However, does the paint on the outside of drinks cans get hot enough to give off harmful fumes

The epoxy-phenolic coating on the inside of the can is the thing that bothers me.  So when I make a chimney stove, I fire it up outside a few times until the coating has burnt off.  Of take it off first with emery cloth.

I'm not sure that the 'paint' is too much of a problem.

And yes, there are plenty of chimney (and other) stove designs that use small food cans.  The Cat Stove probably being the best known.  Have a look at Zenstoves for other burner designs.

Of course, most food cans are also lined with some polymer, probably the same sort of epoxy-phenolic coating as used in drinks cans (even if a different colour).

> The burner will never get significantly above the boiling point of meths, which is fairly low, so I would guess not.

That's true of open-cup burners, but not of chimney burners, where the 'chimney' is in the flame path.

> http://www.dow.com/productsafety/finder/bisphenol.htm

Anything in particular that you think is significant in that link?

(I note the Physical Hazard Information, which notes the toxicity of combustion products, as per my concern.)

Steel wool takes the paint off fine. The finer the grade, the better the finish, but you have to use a bit of elbow grease.

Even in good weather, i tend to cook in my porch, just through habit.

I've lost count of the new burners i've done this with, often demonstrating their use to theburners new owner.

I've suffered no harmful effects, that i know of.

*cough cough*

Include a little history in your walks. Pecsaetan - Ancient Derbyshire, Staffordshire and South Yorkshire - http://pecsaetan.weebly.com/

> Even on open-well jet (pepsi) burners, when started the stove burns as an open burner, so at that stage is the inner wall not exposed to flames: perhaps paint side out would be better if less pretty?.

The flames when starting are quite weak, and the sidewalls _are_ cooled by the fuel in the pot.  In chimney stoves, the chimney gets _much_ hotter.  I know, I've burnt myself foolishly trying to pick them up too soon after they've gone out...  And the EP coating chars and is removed.

Paint side out where?  When making the inner wall?  Can't see it making too much difference, as the temperature difference across the wall in minimal.  I've not noticed the coating on inner walls being charred.  It would at least mean that any charring products would be held within the vapour chamber, or escape via the jets for a potentially more complete combustion in the burner flame.

BTW, you'll probably find that any alumimium container intended to hold product has some form of EP coating; aluminium is rather reactive, so, if the thin oxide layer is scratched, may react with the pot contents.

Have you looked up the MSDS for tin fumes...?

;-)

> did you like http://www.donsmaps.com/stoves.html ?

Hadn't looked.  Have now.  The 'virtual wick' is the same technique used in the 'Frumlight' stove.  See somewhere in the depths of the meths stove Q&A thread...

As for the issue of trying to avoid any toxic output from a burner, well that seems to be a reasonable aim, but, in reality, hard to avoid completely.  Combustion is a complicated subject, and odd chemical things happen in flames, leading to unexpected products.  The simple school chemistry of burning ethanol in oxygen to produce pure CO2 and H2O isn't the whole picture by any means.

So, provided you've burnt off the epoxy in an unenclosed space, or have removed it by other means, then the amount of toxic material released on subsequent burns is likely to be very small.

Plenty of people use these sort of burners.  What the long-term consequences are, maybe we don't know yet, but I don't think anyone has died yet.  So there may be a risk that we're not aware of.  Thus, it's always got to be personal choice on how much risk you're prepared to take, based on an as yet unidentified risk.

It would be nice if the physical hazard information was a bit more specific about exactly what toxic products are released on burning, but, as I said earlier, combustion chemistry is quite complex.  Maybe an opportunity for a small research project for someone with access to a gas chromatograph: anyone know any Uni chemistry departments looking for reserach projects for students?

> did you like http://www.donsmaps.com/stoves.html ?

Just went to the home page, which is interesting, having studied paleoanthropology a little.

> They don't look that bad so far, am I missing something?

I was being a little facetious, hence the smiley.  My point being that if you look hard enough, you'll generally find that most things are 'toxic' to some degree.  A google for 'tin toxicity' will yield useful information, suggesting it's largely benign, but quickly yields this observation about tin vapour.  Again, no real indication of the severity of the problem, but an indication that there may be an issue.

A quick skim suggests that organotins may be cause for concern (Tin is in the same chemical group as carbon, so can be encouraged to take part in organic (carbon) chemistry).

General good advice is to try to avoid inhaling any combustion products of organic chemicals, and to ensure a well-ventilated environment. Especially true if there's an unusual smell, as 'pure' organic combustion yields CO2 and H2O, which don't really register with our sense of smell; many other potential partial combustion products do (CO, sadly, not one of them).