Naked Science Forum

Non Life Sciences => Chemistry => Topic started by: bigwill on 30/06/2007 23:02:42

Title: Smoothing edges of perforations on perforated Aluminium
Post by: bigwill on 30/06/2007 23:02:42

I have some perforated sheets of aluminium, about 18"x30", and about 2.5mm thick. I'm trying to make electrostatic loudspeakers with them but the edges of the perforations are too sharp causing corona leakage off of them.

Is it possible to put these sheets in a bath of sodium hydroxide and let it disolve the edges? Is this feasable?

Title: Smoothing edges of perforations on perforated Aluminium
Post by: lightarrow on 02/07/2007 08:42:38

Quote from: bigwill on 30/06/2007 23:02:42

I have some perforated sheets of aluminium, about 18"x30", and about 2.5mm thick. I'm trying to make electrostatic loudspeakers with them but the edges of the perforations are too sharp causing corona leakage off of them.

Is it possible to put these sheets in a bath of sodium hydroxide and let it disolve the edges? Is this feasable?

You would also dissolve the rest of Al. Why don't you grind those edges?

Title: Smoothing edges of perforations on perforated Aluminium
Post by: Bored chemist on 02/07/2007 20:48:46

I can think of 2 reasons for not grinding them. There are lots and they are too small to get at.
I'd try etching it in NaOH; if that didn't work I'd try HCl but whatever I tried I'd do it on a small test piece first so if it failed I didn't trash anything important.

Title: Smoothing edges of perforations on perforated Aluminium
Post by: bigwill on 03/07/2007 19:01:20

I think I'll experiment with various bits of Al and see what it does.

Title: Smoothing edges of perforations on perforated Aluminium
Post by: ukmicky on 03/07/2007 23:53:39

Instead of removing material to smooth out the sharp edges cant you have to the aluminium powder coated or sprayed with some form of paint or lacquer instead

Title: Smoothing edges of perforations on perforated Aluminium
Post by: bigwill on 04/07/2007 13:14:49

Quote from: ukmicky on 03/07/2007 23:53:39

Instead of removing material to smooth out the sharp edges cant you have to the aluminium powder coated or sprayed with some form of paint or lacquer instead

I have tried to lacquer the panels but the sharp edges repel it and that is the most important place the lacquer needs to be

Title: Smoothing edges of perforations on perforated Aluminium
Post by: another_someone on 04/07/2007 14:53:29

Quote from: bigwill on 04/07/2007 13:14:49

I have tried to lacquer the panels but the sharp edges repel it and that is the most important place the lacquer needs to be

Maybe you could use this to your advantage.

If the sharp edges are repelling the lacquer, then coating the aluminium with lacquer to protect it from acid would help prevent the acid from eroding the main body of the aluminium, while leaving the sharp edges more exposed to the acid.

Title: Smoothing edges of perforations on perforated Aluminium
Post by: lightarrow on 04/07/2007 18:44:55

Quote from: another_someone on 04/07/2007 14:53:29

Quote from: bigwill on 04/07/2007 13:14:49

I have tried to lacquer the panels but the sharp edges repel it and that is the most important place the lacquer needs to be

Maybe you could use this to your advantage.

If the sharp edges are repelling the lacquer, then coating the aluminium with lacquer to protect it from acid would help prevent the acid from eroding the main body of the aluminium, while leaving the sharp edges more exposed to the acid.

Genius!  [:)]

Title: Smoothing edges of perforations on perforated Aluminium
Post by: ukmicky on 04/07/2007 21:33:12

You need to use an etching primer  but be careful as some which can be used for steel are to strong for aluminum and may need diluting,

Title: Smoothing edges of perforations on perforated Aluminium
Post by: bigwill on 05/07/2007 23:52:13

Quote from: another_someone on 04/07/2007 14:53:29

Quote from: bigwill on 04/07/2007 13:14:49

I have tried to lacquer the panels but the sharp edges repel it and that is the most important place the lacquer needs to be

Maybe you could use this to your advantage.

If the sharp edges are repelling the lacquer, then coating the aluminium with lacquer to protect it from acid would help prevent the acid from eroding the main body of the aluminium, while leaving the sharp edges more exposed to the acid.

Clever!!