[Uncle Erik]

Quote:

Originally Posted by cotdt /img/forum/go_quote.gif To get an even finish, I just polish the aluminum with fine sandpaper and then put it in strong Phosphoric Acid.

Really? I didn't know phosphoric acid did that to aluminum. I am absolutely going to give it a try. Do you use Naval Jelly, or do you order it from a chemical supply place? How long do you leave it on/in and how do you neutralize it afterward? That sounds like the perfect finish for a few projects I have.

 

[cotdt]

Quote:

Originally Posted by Uncle Erik /img/forum/go_quote.gif Really? I didn't know phosphoric acid did that to aluminum. I am absolutely going to give it a try. Do you use Naval Jelly, or do you order it from a chemical supply place? How long do you leave it on/in and how do you neutralize it afterward? That sounds like the perfect finish for a few projects I have.

Naval Jelly should work. I let it soak for 2 days, then rinse with water and let it sit in air.

 

[Mandrakespain]

I do not know if this may help, it is a tutorial of how to re-finish watch bracelets, with both brushed and polished effect:

TimeZone: Omega: Tutorial: Bracelet Refurbishment (Bond SMP, Pic intensive)

May be useful for the small parts...

 

[MACDRU]

Brushing aluminum with any grit will cause oxidation in the long run. For aluminum, a slightly hazy coating will form (not a big deal). Usually products that have a brushed aluminum finish are brushed (or etched) with that finish then clear anodized for protection and durability.

 

[nickyboyo]

Here we go vixr, the amp and casework i have just finished. Very similar design concept, different approach.

[/IMG]
Mine's with a folded sheet construction, but i really do like your cut out plate concept

 

[DanE-ARC]

I routinely make brushed aluminum signs up to 5' x 10'.  There are three ways we go about this for large sheets of metal that require perfectly straight brush marks.
 
1. Purchase brushed aluminum in premade 4x8 or 5x10 sizes - commonly .040 gauge.  Sign suppliers generally have this item in stock at an economical price.  If you need thicker aluminum see #2 & #3.
 
2. Cheapest - Hand method - attach your aluminum sheet to a stiff flat backer.  Wrap a 2x4x12" block in 3-4 paper towels and your sand paper - you will get two uses per sheet - the paper towel acts as a cushion so that the sandpaper gets full contact.  We like coarse marks so we use 300 grit.  Using a straight 2x4 as a guide and 2 helpers have them hold the 2x4 against the metal at the same height (make sure they know how to use a tape measure so your marks are even) and run your sanding block against the guide to brush the surface.  Overlap each run 50% and change paper often.
 
3. Easiest - if your doing a lot of this work get a drum sander, disconnect the dust collector so that you do not suck sparks into your big bag of wood dust and run the aluminum through several times alternating direction.  The first couple of inches usually do not sand well so flip the piece every run.  I dont recommend begging this off a friend with a hobby drum sander - chances are you will smoke their machine.  A professional wood shop will have rugged equipment.  We pay $75 to have 4x8 quarter inch plates brushed at our local wood shop - again.... tell them to cut off the dust collector or they may get miffed at you for burning down their shop.  Keep in mind drum sanders run at high RPM - you will use higher grits and end up with finer finishes than hand sanding due to the number of times the grit hits the metal.

 

[wakibaki]

We tried engine turning on a CNC mill at work, the effect was very good, but very expensive, because the brush would wear and the effect changed from one side of a panel to another, so you had to change the brush frequently. One botched roundel and the panel was irretrievable in some cases.
 
w

 

[vixr]

Quote:

Here we go vixr, the amp and casework i have just finished. Very similar design concept, different approach.

[/IMG]
Mine's with a folded sheet construction, but i really do like your cut out plate concept

AWESOME!!!    the wood is beautiful...wow just noticed how slow I am...'09?

 

[daigo]

Quote:

AWESOME!!!    the wood is beautiful...wow just noticed how slow I am...'09?

 
I do find it amusing you're responding to that guy's post after three years.

 

[vixr]

Quote:

 
I do find it amusing you're responding to that guy's post after three years.

I find it amusing that you pointed out something I already pointed out...