William Wixon wrote:

this is a 4" disc, with not much concavity, does it have to be aluminum,
does it matter how thick it is? oftentimes (if the project doesn't have a
heavy time restriction on it) i'll just keep my eye open for objects at the
local recycling center/dump. how about *getting* a tank end and cutting
(plasma, jigsaw, etc.) a 4" disc out of it already pre-formed? sometimes i
get lucky and find exactly what it is i need at the dump.

We don't seem to have dumps like that where I live. We have "transfer stations"
and people do drop metal off there but no one is allowed to pick through it.
That is a vanishing way of life in the Greater Seattle metropolitan area, sad
to say.

I have decided to make a different kind of vent - a tube with a top-mounted
vent. I know how to hold a tube vertical and scribe it to a curved surface.
Then I'm going to cut out the tube and grind it until it fits the tank end
closely, then hold it in place and scribe around the tube and cut a bit inside
the scribe line, then smooth the cut a bit and then weld the tube in place.

The surface isn't regular is the problem - it will have to be off to the edge,
and the tank end isn't spherical. Unless the surface is regular a rotating
disk Weber-style vent won't work.

Grant

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