Sheet aluminum for polishing

[jlcustomz]

I,m getting ready to start a custom alum crossram intake project.http://ls1tech.com/forums/generation-iii-external-engine/1518676-performance-design-intake.html
I,ve done several raw fabrication projects from #316 stainless or various aluminum that i,ve fully polished. I already have a bit of .063 # 3003 h-14 alum sheet & a little 6061 plate. I figure for the runners on this intake, I,ll probably 2pc hammerform & tig weld from sheetmetal.Possibly samemethod for most of my 2 into 1 plenum setup.
My question :: is 3003 decent for polishing & holding a shine or should I look for another grade of alum. Also is .063 probably thick enough for my intake or should I consider thicker. Not everyday questions, I know.
By the way, anyone who appreciates handformed alum should check out my bedcover in the photobucket link. Learned to weld alum on that project.
http://s1094.photobucket.com/profile/jlcustomz1

[Jim Nilsen]

It should polish up just fine. Aluminum is one of the best materials to polish to a mirror finish on the planet.

[latoracing]

The softer the aluminum is (3003 H34) the easier it is to polish. The down side to it is it will not stay that way long, espically under the hood of a car with alot of heat. Clear coating is an option, but can turn yellow. Anodizing can be done and will take a little out of the shine, and will stay for quite some time. If you are hammer forming aluminum, start with a sheet that is as soft as you can get. If you start with 6061 T6511 it is fairly hard to begin with, and the more you work harden it the more it might split, or be a pain to shape. 5052 H32 is a decent alloy to play with, is workable, fairly easy to get, semi cheep, and welds almost as good as 6061 alloys.
I'm probably boring you, but if you want shiny sheet metal, get used to lots of re-polishing if it is not coated.

[jlcustomz]

Thanks. The 6061 I have Will NOT be getting bent If I use it for flat portions of my plenum.. I may look into local availability of 5052 if it'll hold a shine better than 3003 for my runners. I do know how to anneal with a torch if (when) needed. Holding a shine is my concern on polishing, not the actual polishing.I know from personal experience that 6061 plate takes & holds a shine better than many other grades,although it,s not suitable for bending & shaping. I may even consider powdercoating this thing, Which I can get back to for a while anyways.