Making a Microporous Aluminum Grid

I recently bought a Scripto Windresistant igniter,
which is a butane powered gadget for starting
barbeques and the like. Sort of like a big disposable
cigarette lighter, but with a long wand between
the fuel supply and the burner, and a piezoelectric
starter. Only $6.
I was impressed by the cone of flame, which had
a bright blue cone inside a purple flame, like a
Bunsen burner. I thought it would be interesting
to see how much damage it could do to aluminum
foil. I only had the thick "heavy duty" foil, from which
I tore a strip. I folded it into an L-shaped channel,
which I stood up on one leg, so I had a vertical target.
I could heat it up to orange heat in a couple seconds.
I thought I should be able to burn through it in just a
few seconds more, but even at 30 seconds I wasn't
making any more progress.
The spot I had been attacking was obviously disturbed,
but not punctured. Then I noticed there was light
coming through. I held it up to the light, and I could
see it had turned into an array of very closely spaced
tiny holes. I wished I still had my Radio Shack Pocket
Microscope, so I could see how regular they were.
I was amazed that the foil had formed this array,
rather than just melting and/or burning. Once formed,
the array was very resistant to further change.
The phenomenon is very reproducible. Every time
I tried it, it worked just fine.
Hmmm... there must be something clever I can do
with this discovery. I wonder if it has a name?
Reply to
Mark Thorson
Loading thread data ...
|> I recently bought a Scripto Windresistant igniter, |> which is a butane powered gadget for starting |> barbeques and the like. Sort of like a big disposable |> cigarette lighter, but with a long wand between |> the fuel supply and the burner, and a piezoelectric |> starter. Only $6. |> |> I was impressed by the cone of flame, which had |> a bright blue cone inside a purple flame, like a |> Bunsen burner. I thought it would be interesting |> to see how much damage it could do to aluminum |> foil. I only had the thick "heavy duty" foil, from which |> I tore a strip. I folded it into an L-shaped channel, |> which I stood up on one leg, so I had a vertical target. |> |> I could heat it up to orange heat in a couple seconds. |> I thought I should be able to burn through it in just a |> few seconds more, but even at 30 seconds I wasn't |> making any more progress. |> |> The spot I had been attacking was obviously disturbed, |> but not punctured. Then I noticed there was light |> coming through. I held it up to the light, and I could |> see it had turned into an array of very closely spaced |> tiny holes. I wished I still had my Radio Shack Pocket |> Microscope, so I could see how regular they were. |> |> I was amazed that the foil had formed this array, |> rather than just melting and/or burning. Once formed, |> the array was very resistant to further change. |> The phenomenon is very reproducible. Every time |> I tried it, it worked just fine. |> |> Hmmm... there must be something clever I can do |> with this discovery. I wonder if it has a name?
It sounds like you oxidized it into alumina before it could melt leaving a refractory material with voids where outgassing occurred. Try it with several layers pressed together and cover up the air holes a little to get a carburizing flame. If it inner layers melt away you know you were making alumina. Should be worth a Faces in Science mention in USA Today followed by a Leno and maybe an SNL walk-on, then the book tour and finally your own Fox series. :-)
Reply to
Keith Michaels

PolyTech Forum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.