This is not an easy thing to do.
The aluminum is soft enough it will warp, and it is tough, but not
impossible to get it back flat again. Big rolls- you will need 4' wide
rolls, that will roll 1/8", and run it back and forth a bunch of times,
and as long as you havent overdone it, and created some bowls, that
will take it back pretty flat.
My advice, though, is not to try to texture aluminum sheet yourself.
Consider a few other directions-
1- buy pre textured sheet. The big dogs in this field is Rigidized, in
Buffalo New York- they make pretextured sheet in a wide range of
patterns, in a variety of metals. Their main thing is stainless, which
is better than aluminum for this anyway- it takes a texture better, its
harder so it will wear better, its thinner, lighter, tougher, and
resists oxidisation better too. Aluminum will oxidise, and get white
junk on it, unless you clear coat. The stainless will just sit there.
However, if you insist, I am pretty sure Rigidized will roll aluminum
for you.
http://www.rigidized.com/
2-If you must texture aluminum, the way it is done is with textured
rolls- 4' wide, probably a minimum of 4" in diameter, with the texture
ground or pounded into it. Then the aluminum is fed thru, powered, of
course, minimum of maybe 3hp to do this. 1 shot, the whole piece is
textured. This is how rigidized does it. I realize, this is not cheap
or easy- but what you wanna do isnt common, and there is a reason for
it.
3-Other metals are gonna hand texture a whole lot better than aluminum.
I have been texturing a lot of stainless lately- I use needle scalers,
with a variety of modified needle shapes, and air chisels with modified
tips. Stainless is hard enough it doesnt wanna bowl near as much. Of
course, we still have to run it back and forth thru the rolls a few
times, flipping it, to get it flat again. But I have been having good
success with 1/8" 304 sheet this way.
4- I am not sure how your etching is gonna work- thats something I dont
know much about. But I have also done texturing of surfaces like this
with sandblasting- you can get this cool adhesive backed rubber sheet,
in rolls. You cut out your pattern with an exacto knife, and peel off
the negative parts, then blast. Works pretty well, with the time spent
blasting controlling the depth of the texture. You could buy the rubber
yourself, then pay someone who is setup to blast. The rubber stuff can
be gotten at big signmaking supply companies- they use it to make
sandblasted wood and stone signs. TP has it too.
http://www.tptools.com/