Chassis Plate Finish

[HEADinaJAR]

I'm looking at a number of options for finishing. I bought a 17"x10" Hammond Aluminum chassis plate. .051" thickness. I'm going to do something faux organic to this plate. I'd like it to look like either a blacksmith smelted this thing in the bronze age, or it came out of the ground with striations, veins or uneven patina to it. I may hammer or grind/chisel the thing. The point is to do it myself. Hopefully without spending to much money or using chemicals that I cant store and use for other fARTsy applications.

I am going to form the front and back plates by 90 degree bends to the 17" length at 2" from either end. This will sit on a wooden base and sides. So, the box will be 13"x10"x2" with tubes and transformers on top. These bends will hinder the type of hammering that can be done.

Here one of the looks I'd like to achieve:http://gfish.livejournal.com/187606.html

I don't own a chisel that is meant to be used on aluminum and the thickness of the plate will dictate how much chisel work can be done to it.

I really don't like the look of oxidized aluminum, or polished and lacquered. I'm going to test some pigments/metal leaf suspended in lacquer for heat resistance. Try to make it translucent so the metallic quality of the aluminum can be used in the finish. I haven't seen heat rated paint that was not meant to be a solid-colour finish. Maybe:http://www.pinnaclegallery.com/123.jpg or http://www.artisandp.com/images/full...texture-22.jpg I could do these if it wasn't for the heat rating.

How hot will this amp get? Will it cause a yellowing or blackening to the finish? This is a Tubelab SimpleSE w/ Allied 6K7VG, Edcor GXSE15-8-5K, JJ e34l, 5AR4 and 12AT7 tubes.

Has anyone used Birchwood Casey's Aluma-Black? http://www.kitterytradingpost.com/pr...83/prodid/5490 This is a gunsmith product for bluing aluminum parts on guns.

Here's an interesting alternative for blackening aluminum:http://chestofbooks.com/reference/He...-Aluminum.html

Anyway if anyone has any experience with any of these ideas, or can add to them, it would be great to hear about them.

Thanks, Rob

[Conrad Hoffman]

Other than anodize I've never seen a chemical finish on aluminum that I liked, and anodize certainly isn't what you're looking for. I'd be looking for a paint, maybe do some research on faux finishes. There are also some texture coatings used for automotive rocker panels and such. The usual Hammertone and wrinkle finishes are probably too conventional for you. I like the old GR test equipment finishes, and there were some threads here a long while back on recreating them. You might look into crackle finishes.

[bequerel]

Maybe you could have a local metal shop sandblast it with too big and not uniform grit and go from there. It would probably make it look like it was pitted from many years in the soil if you then painted it black, wiped off the black paint so it sunk into the to the pits, and then used some lighter color on the lands between the pits.
Btw. caliper laquer used for car tuning is thick and cream like before it dries to a porcelain like surface. It is available in many colors, and I think it would be possible to to do something fun with it before it has hardened. Like scarping, pressing something into it etc. Just some brainstorming. Good luck!

[rcavictim]

Tie the aluminum chassis to the rear bumper of your car with some rope and go for a drive on a gravel road.

Do this before mounting any components to the chassis.

[Eli Duttman]

Because of the TIGHTLY adhering oxide coat, Aluminum is very difficult to finish.

Spray can hammertone finishes, in several colors, are available. The spray stuff sticks quite well to many materials, without any extra help. However, you guarantee a good end result by starting with a self etching primer bought at an automotive outlet.

Degrease and dry the sheet Aluminum. Prime the clean surface and allow the material a couple of days to harden well. Then build up the surface with several coats of hammertone spray on. Allow PLENTY of time for the completed finish to harden well, before attaching any hardware.

[nhuwar]

If you use a surface prep it's easy to finish.


Here you can use this.

http://www.chemical-supermarket.com/...FQHHGgodT3YHnA

And you won't have any problems just be careful because it has hydrofluoric acid in it which is by far one of the most dangerous acids on the planet.


But it's only a few percent, just were nitrile gloves.

Hope this helps
Nick

[VictoriaGuy]

Originally posted by Eli Duttman
B Prime the clean surface and allow the material a couple of days to harden well. Then build up the surface with several coats of hammertone spray on. Allow PLENTY of time for the completed finish to harden well, before attaching any hardware.

The hardening process can be helped along by a few cycles in a warm oven.

.....Wife returns from shopping: "What's that smell in the kitchen?" "Nothing- just something from the workshop downstairs..."



John

[nhuwar]

I have been wanting to try it out but have yet too. I've also use a strong solution of sodium hydroxide and water, about 20 to 30 %.


It's works well but you have to clean the surface throughly after you etch it do to the particulate surface oxide that forms but it wipes off easy.



The only problem is your left with a large container of highly dangerous and toxic sodium hydroxide solution.


To dispose of it when I'm done I plan to make some salt LOL and then it's easily disposed of LOL

But in this concentration I do conceder it more dangerous then the prior mentioned surface prep.


So I don't suggest unless you really know how to handle your self around dangerous chemical.


So in all cases Be careful no matter which method you use. Because when it come to AL you need some form of chemical surface prep to do it right and make the finish last.


Nick

[monkeywrenching]

I have used several different ways to texture aluminum and stain it. You can use different grades of sandpaper like 35 grit and say 150 so there is contrast. A wood chisel takes time by scraping and pushing. You can use a rip or cross-cut saw or a combination of both. Hold the blade with both hands, teeth away from you, and use like you are scraping or filing at about 30 deg. A wood rasp leaves a rough finish depending on how hard you use it. Any abrasive can be twisted, poked, rubbed, or what ever. A scotchbrite pad on your thumb twisted can give you a turned finish. An automatic center punch can be used to give you a stipple effrect. I have used "prussian blue" or a sharpe to produce a stain. Also india ink brings out the texture with a black on silver look. Practice a lot first.
Just a few ideas anyway.
Dan

[JoshK]

I like the patina look myself, but hit a dead end trying to find something that would patina aluminum, for all the reasons stated above. You can paint aluminum like Eli said, I've had very good luck with self-etching primer (bought at pepboys here) and then painted.

One project, I wanted a oil-rubbed bronze look, so I epoxied a sheet of copper to the aluminum and patina'd the copper. The epoxy keeps the aluminum and copper from reacting with eachother. You can then machine the two as the epoxy machines well. The aluminum gave the strength as copper thick enough to be strong is way too expensive.

Copper patinas well. I used liver of sulphur. The key is how clean you can get the copper before treating. If your interested, I'll detail the steps I learned.