Deep pitting on engine

[Guest]

Down to the last few weeks of my restore. Will be pulling the engine pretty soon for a top end rebuild and, most likely, to fix the bottom of the case around the oil drain hole to stop a leak. I don't have access to a sand blaster and so I've been using a circular wire brush attachment on my drill to clean up the covers/emblems, etc. Prolonged exposure to the elements has left all kinds of stains that will not come off unless I cut through the entire first coat. After doing so I am noticing that, while extremely bright (and pleasant looking), I have exposed some pitting in the aluminum. The deeper I go, the worse it gets ...



Any ideas? Will this come out with a wet sand and buffing? Keep in mind this is only after using the wire brush and nothing more.

GSP

[JEEPRUSTY]

Ypur brush is doing the damage cease immediately

use wet sanding to smooth out the bumps then re photo and show us.

[gspower]

Ypur brush is doing the damage cease immediately

use wet sanding to smooth out the bumps then re photo and show us.

Rodger that. It's really pitted underneath, as if they came out rough from the factory but the coating that was applied smoothed 'em out.

Thanks though.

GSP

[eil]

Do you have any "before" pictures? Maybe a previous owner applied some kind of coating?

The covers didn't come pitted from the factory, but they did have a kind of clear coat applied. On weathered bikes, this clear coat erodes and bubbles, trapping moisture and dirt which in turn causes pitting. Most of my 850 engine is covered in it, unfortunately.

There are chemicals which will remove the clear coat easily. I believe one is called aircraft stripper or something like that.

[Steve]

As the Jeepster said, it's your wire brush that is dragging away the aluminum.

It was not "pitted" when you started, you dragged away all the smooth parts.

.

[greenbraes]

lots of wet and dry, slowly getting smaller grit, it should come good but some areas may take some time...patience will be the key here and it will be worth it in the end

[posplayr]

Uh steel wire wheel on aluminum??? Not sure why you would ever want to do that. If you are using steel it will cut deeper than any corrosion deeply scouring the metal. Maybe a brass wire wheel. It might actually leave a smoother surface.

You are going to need some 250 now to cut down to the low spots. The problem with using a sander is it is too easy to get a flat spot. I suspect the brass wire wheel won't do too much to smooth that out now .

Need a rubber sanding Block and 250 to get rid of the worst of the damage.

[barnbiketom]

I've found that the corroded clear coat usually gives that nasty look on them, and use stripper to take it off.. then underneath the aluminum is usually fairly decent, and agree, that the wire wheel/drill sander etc makes it much WORSE... but in this case ,you need to sand out the damage then polish with buffer and 2 or 3 grades of compound, ending up with very fine rouge or whatever you call it.

[gspower]

Uh steel wire wheel on aluminum??? Not sure why you would ever want to do that. If you are using steel it will cut deeper than any corrosion deeply scouring the metal. Maybe a brass wire wheel. It might actually leave a smoother surface.

You are going to need some 250 now to cut down to the low spots. The problem with using a sander is it is too easy to get a flat spot. I suspect the brass wire wheel won't do too much to smooth that out now .

Need a rubber sanding Block and 250 to get rid of the worst of the damage.

The aluminum was in really bad shape and I could not clean it up adequately to my liking. Brass would have been smarter. . This will require more work but I think the end result will be nice. The picture is very close up and looks deeper than it actually is. I will wet sand and post the results.

UPDATE: I will be the first to admit that wet sanding through the wire brushing was labor intensive but I am happy to report its looking BEAUTIFUL. Will post pictures when I finish. Future note: 100 grit would have made the job easier.

[gspower]

This was after a quick 180 sand, followed by 220, followed by 400, 800, 1000, 1500, and 2000. I think I might have gone to quickly because, as the metal feels smooth, I can see scratches made by the sandpaper shining through. IT does look really nice, though. Any suggestions?

[GateKeeper]

2000 grit and you still have all those scratch marks ? it should be close to polished using that grit of paper....

for arguments sake, hit the part with the buffing wheel and see how it turns out before you continue to sand anymore

I used a brass wire wheel, no wet or dry sanding of any kind, and then a buffing wheel with 2 different compounds, and my parts came out OK

http://www.thegsresources.com/_forum/showpost.php?p=1568892&postcount=422

http://www.thegsresources.com/_forum/showpost.php?p=1569416&postcount=426

http://www.thegsresources.com/_forum/showpost.php?p=1569936&postcount=428

I didn't get rid of every single minute imperfection, but close enough to my liking...

.

[Sci85]

That's a lot of scratching left in the surface. It will polish up but not to a mirror finish. You most likely moved through the lower grits too quickly. I usually start at 220 or 320 depending on the surface and type then move up to 600 -800. Then on to the buffing wheel and polishing compounds. No need to go to 1500+ grits. The black and brown compounds will do the job if you properly sanded out the larger scratches. Use the compound sparingly (no heavy black lines - that's too much compound). If I sanded, I start with black on the sisal wheel. If the part is already smooth, then skip the sandpaper. Here's a link that will help get you started. Good luck and show us ther results.

http://www.caswellplating.com/buffman.htm

[posplayr]

The aluminum was in really bad shape and I could not clean it up adequately to my liking. Brass would have been smarter. . This will require more work but I think the end result will be nice. The picture is very close up and looks deeper than it actually is. I will wet sand and post the results.

UPDATE: I will be the first to admit that wet sanding through the wire brushing was labor intensive but I am happy to report its looking BEAUTIFUL. Will post pictures when I finish. Future note: 100 grit would have made the job easier.

You have now had at least 5 people tell you that if you are looking for a polished finish, you have to avoid making deep scratches. 100 grit is about the worst thing you could do. The idea is to use the finest grit that will get through the oxidation.
What has not been mentioned is the use of a power tool. When the tool moves quickly it has the effect of reducing the roughness of the paper. It the cover was really really bad, I would use 250 grit on a power orbital sander/palm sander. Only if that was not going through then sand down further with like a 150 grit.

Again, you do not want to sand out all of the imperfections with such a rough grit as you will have to just take out even more during polishing. You just want to remove enough material till you are withing sanding distance of the firer grits.

[tkent02]

Might I suggest a wrinkle paint finish on this one, or better yet wrinkle powdercoat.

Or keep it for a spare and find a nice shiny one on Ebay for $10.

[posplayr]

Might I suggest a wrinkle paint finish on this one, or better yet wrinkle powdercoat.

Or keep it for a spare and find a nice shiny one on Ebay for $10.

Yes, a black powdercoat or a spackle paint, because the glint of those scratches from the sun with show up even through a crinkle clear.