Aluminum Polishing Tips for Damaged Pieces?

[InfiniteGSX]

Soo many things on my motor is polished now. I shaved and polished my Hyundai valve cover, my 3" 1G Intake Pipe, Tubular Headers (well they were chromed, but I repaired them), Hard IC Pipes and a bunch of other little things. But on my really nice peices, like the valve cover, they aren't perfect. Sure the polishing is... but where it said DOHC... some areas have pits... like where there was an air pocket. On my 3" Intake tube, there are TONS!

What can I do about this? Fill it with anything? I was thinking Solder on the valve cover, since its such a small pit, if it filled... I could sand it down and polish and you might not notice the polished lead next to the polished aluminum.. but I'm not sure about this... and the Intake would take weeks to fix. What can I do?

 

[bpestilence]

Unfortunately this is why it is difficult to polish cast aluminum. The casting is always porous and you will uncover this porosity when you start to grind on it. I would say weld the pockets up, but this will probably only make it worse. Welding on cast aluminum is, for much the same reason, the most difficult welding to do.

 

[kawboy]

You have to keep sanding until they're gone

Likely never be perfect, but can be damn close.

 

[Defiant]

If you think it's worth the bother, check eBay for aluminum solder. Lead solder won't adhere to aluminum, but they make alloys for use on aluminum. You'll need to get all the old polishing contaminants out of the pits you're filling, and I don't know how well the filler will polish up.

 

[InfiniteGSX]

Hmm... I've never thought of that. Well if I do it, it will be on my intake... Cause I don't care about that thing as much as my Valve Cover. I ended up shaving the DOHC 16VALVE off because I couldn't get the surface around the letters polished like the rest. I still have to figure out the coloring (stained look in the aluminum) and how to get rid of it, but I'm more worried about that pit. I spent all that time on it just to have an ugly hole

 

[Calan]

As strange as it sounds, I've actually had some luck with mixing fine aluminum powder (made by sanding a piece of stock with 220 grit on an orbital) into some epoxy.

It comes out a bit darker than raw aluminum, but it is workable and fills the voids.

I haven't tried this on hi-heat applications, but most epoxies are fairly resistant to heat and chemicals...so it may work with varying degrees of success.