At 09:10 AM 8/13/2009, peter foti wrote:
>yes, press and peel blue. I haven't tried aluminum but I plan to in
>the future. I don't think the alloy would make much difference in
>terms of getting the pnp to stick (although it ∗might∗ make a small
>difference during etching). I generally use 6061 for machining and
>5052 for sheet metal and bending applications. Aluminum tends to form
>an tough oxide layer very quickly (aluminum oxide is sapphire, yo).
>And I bet heating it only makes this worse, but I'm no material
>scientist so take this with a grain of salt. Also your large surface
>area can't be helping. The fact that you're getting it to stick at all
>suggests that it can be done. Its just a matter of developing a
>procedure that works.
I'm no chemist, either, but I do know that sapphire (corundum) is
∗an∗ aluminum oxide. There are several Al oxides, though. Super-soft
graphite and ultra-hard diamond are both pure carbon, right? But I digress...
As you say, aluminum does form a layer of oxide pretty quickly, so
you should clean it just before trying to stick something to it.
Etching or lightly sanding could help something adhere.
John