Thread: bead blasting aluminum part II

I want to bring back the bead blasting aluminum topic again please. Various parts of the ct 70 are aluminum like left side of motor (clutch cover?), the wheel hubs, the head, motor casing (?), so I can;

a)bead blast and then clear coat (or paint) or
b)remove clear coat from factory, polish, and re-clear coat or
c)polish and buff but not do clear coat?

What clear coat product is best to use and do you always use the same for parts that get hot and those that don't? Maybe the head should not be clear coated? I think I've seen the left side clutch cover bead blasted (excluding the Honda emblem) and then painted silver -true? and the reason I ask is because this part is aluminum and could be polished so why would you paint it?-maybe I'm just confused on some of the details here.

Please help clarify if all aluminum parts are treated the same or if there are exceptions to the rule. MY goal would be to polish and clear coat so there is a deep sheen and chome shine throughout the bike (minimal silver paint).

I just started glass bead blasting the back shocks and I was able to take steel wool and scotch bright pads to bring them back to a polished finish. They look good and I don't want them to tarnish over time. Thanks for helping a newb in time of need. 8^|

The only engine parts that were painted originally were the cylinder and sidecovers.

I would never paint the cylinder head, just blast it clean and leave it bare aluminum. I clean mine occasionally, with a very careful, minimal, application of brakleen followed by compressed air (engine cold, rags protecting anything painted). No clearcoat is going to withstand that kind of heat without at least yellowing and it would affect heat dissipation anyway.

The clutch and flywheel covers were painted cloud silver, but could be polished if you like. Only the cam cover and points inspection cover were polished orignally. The points cover can be successfully clearcoated. The engine cases (center) should be chemically cleaned as they had a smooth, as-cast, surface finish that will be gone for good if blasted.

The lower portions of the shocks had a brushed finish and were clearcoated, as were the upper mounts. The brake backing plates were polished and clearcoated. The triple tree was polished, but not clearcoated.

Clearcoat knocks down the shine of polished aluminum and, since there's no way to prime the metal first, will eventually begin to peel/chip. Thus it's best to use a product that can be easily removed so you don't have to repolish things from scratch. Duplicolor wheel paint clear works well; adheres suprisingly well, resists petroleum spills yet can be easily removed with laquer thinner. I don't clearcoat polished aluminum on custom builds. It looks better and can be maintained by applying paste wax. The occasional touch-up with nevRdull or Mothers mag & aluminum polish is easy enough as long as you don't let the polished surfaces start to turn chalky.

The wheels & hubs were painted cloud silver. The hubs can be polished, but take a good close look at them before attempting this. Those are rough castings and take a ton of work to make look good polished.

Originally Posted by racerx

The engine cases (center) should be chemically cleaned as they had a smooth, as-cast, surface finish that will be gone for good if blasted.

What do you mean by this? It there someway to do this at home or is it something that needs to be sent out to be done?

what clear coat product works well for the rear shocks? Thank you.

Cheically cleaning aluminum is a tad seat-of-the-pants. Go in stages. First, remove all of the grease and dirt buildup. I use mineral spirits & a rag, a toothbrush works well to get the small recesses. Next, try carburetor cleaner on a rag on the remaining discoloration. Anything left after this step has to be removed chemically. DuPont aluminum prep, Naval jelly for aluminum or sodium hydroxide are the easiest to source. Sodium hydroxide is the active ingredient in oven cleaner. Rubber gloves are mandatory. Apply a small amount to a rag and work on a small area at a time, followed by a thorough wipedown with clean wet rags & drying. You only want to leave to chemical on the metal long enough to remove the surface staining and it must be kept out of the inside of the cases. There should be zero chemical residue allowed to remain. You might do this before splitting the cases. It'll be easier keeping the chemicals out of the engine; the tradeoff is that it's more difficult getting the LH case completely clean with the motor in one piece.

It's a nasty process , but there isn't much of it to deal with.

Originally Posted by j1mmy

what clear coat product works well for the rear shocks? Thank you.

Duplicolor wheel clear works well & it's cheap, too