Vapour blasted alloy

[MrDavo]

This is related to my other thread in this section, re polishing a vapour blasted alloy surface which should be gloss, but this topic is how to keep my engine clean? - vapour blasted and looking like new is all very fine, but sooner or later my CB750 is going to be used in typical filthy British weather, ridden accross muddy fields at rallies etc.

Once it has got filthy, how best to bring it back like new - solvents, alloy cleaners, Gunk? or what? Any sort of abrasion would ruin the matt silver finish I now have. Leaving crud on to bake I am sure would stain the cases / fins etc forever, no?

I will try and avoid the dreaded road salt, but you can't use a bike and do that forever.

I could even paint it matt silver over the blasted surface, but to spray it properly the engine would need to come out, and that's not going to happen until it definitely has to, I want to ride it first.

[flatfour]

I use paraffin from a spray gun, followed by compressed air to remove any remaining dirt and dry things off. It seems to work for me!

[Trigger]

You should not vapour blast a engine, if one little glass bead is left, then the engine is finished. What we do @ CB Classic Motorcycle is, first the engine is washed in a high temp parts wash, two days in acid to remove all the paint & lacquer, back in the parts wash, soda basted and then paint, which is cured in the oven.
If the engine is left unpainted then corrosion will set in very fast.

Paint does not key to vapour blasted alloy

 

[MrDavo]

You should not vapour blast a engine

I am where I am with it, which is why I need advice on whether to clean or paint. I'm not 100% sure its vapour blasted or what, but that's the nearest finish I'm familiar with to what I've got. It was done a long time ago and hasn't corroded though, which you would have expected with virgin alloy. that said it lived abroad where the climate is dry.

At least I have dropped the oil pan and found no dirt, beads or whatever, but looking up from the sump plate, with a torch,  the insides of the motor look the same as the outside - very silver with no lacquering from use . At least they did a good job of masking the gasket surfaces, I once had (from an autojumble) some BSA A10 cases that had been blasted, and every gasket face and threaded hole was ruined - result, scrap!

[AshimotoK0]

What I have done is blasted the hell out of the finest glass beads you can get (blast steel  footpegs tanks etc 1st) so that the glass is like flour. I sealed everything and pressure tested it before blasting (see separate post). The glass is so fine that I reckon it would polish rather than ruin everything if a speck got inside  but I am pretty convinced there's been no ingress anyway. Wouldn't trust anyone else to do it for me though and didn't do my 750K0  cases this way. Dunno about paint adhesion but I have a scrap 750 cover that I blasted, so I will do a test on the paint and report back. I will do one cover without ultrasonic cleaning after blasting and one cleaned ultrasonically.

[paul G]

You should not vapour blast a engine, if one little glass bead is left, then the engine is finished. What we do @ CB Classic Motorcycle is, first the engine is washed in a high temp parts wash, two days in acid to remove all the paint & lacquer, back in the parts wash, soda basted and then paint, which is cured in the oven.
If the engine is left unpainted then corrosion will set in very fast.

Paint does not key to vapour blasted alloy

Trigger what silver paint do you use !

[Trigger]

You should not vapour blast a engine, if one little glass bead is left, then the engine is finished. What we do @ CB Classic Motorcycle is, first the engine is washed in a high temp parts wash, two days in acid to remove all the paint & lacquer, back in the parts wash, soda basted and then paint, which is cured in the oven.
If the engine is left unpainted then corrosion will set in very fast.

Paint does not key to vapour blasted alloy

Trigger what silver paint do you use !

Sorry Paul, that is a trade secret 

[Trigger]

Customer did not want it repaired Ken