Remove the engine's aluminum coating

Acemon

New Member
I have '75 Honda and trying to polish the engine covers without taking them off but the factory coating is a nightmare to remove. I've been using 500 grit wet sandpaper, which works pretty well on the flat surfaces (circular motion) but the little/curved areas are nearly impossible to get to.
Suggestions?
 
Oven Cleaner or Aircraft stripper gets the clearcoat off. Make sure you read the directions...dangerous stuff. If you are using sandpaper, go with a higher grit (800-1200) and use it with WD-40 instead of water.
 
Why not take them off? They're intended to come off easily and you need to take them off for a lot of the maintenance work you'd want to be doing.
 
The engine's internals were taken care of last summer and the bike has a mere 122 miles since then. The case and covers are sealed tight and I don't want to go thru that effort again. It's out of the bike and resting on a milk crate, which makes it easy to reach everywhere.
I just bought some aluminum stripper, so I'll give it a try tomorrow.
I should had said that I started with 500 then switched to 1000. Never heard of using WD40 before. Learn something new every day.

Thanks
 
Oven cleaner on aluminum? You do know that sodium hydroxide (the primary ingredient of many oven cleaners,) dissolves aluminum, right? With the side benefit of generating hydrogen gas. :eek:
 
Ya know Glen. Go fuck yourself.
It IS useful to point out that you should never use oven cleaner on aluminum.
Don't be a dick.
 
<turkey lips>

Hey! Wait a minute. Everybody knows I am Lizard Breath!

Git yer shit straight!
 
Acemon, if you really want to make those cases look great, you really should remove them. No trouble, really. MUCH easier that trying to polish them on the engine. Take a look at these two pictures. They are a before and after.

StatorCover1.jpg


StatorCover2.jpg
 
I went through many steps to achieve that result. Because of the deep gouges, and the badge recess that I wanted to eliminate, I started with 120 grit in an air tool. Did some work with rollock disks and some with flap disks. 120 grit leaves some pretty bad scratches, of course. Then I wet sanded with 220, 320, 600, 800. Each time, not switching to the next grit until all traces of scratches from the previous grit were gone.

Then I finished them off with a buffing wheel on a 6" buffer using an emery bar. Then I switched wheels and did rouge.

The Harbor Freight buffer was not expensive. Without it, I could have never gotten this result. Buffing aluminum to a show polish requires high speed, (at least 3000 rpm,) and enough power to build some heat in the piece. The polishing bars are abrasives in tallow. It takes some heat to melt the tallow and make the abrasive really work. Trying to use a buffing wheel in an electric drill is not very effective because it just doesn't have the speed and power to make it happen.

Do yourself a favor and remove those cases, then you can do a proper job of polishing them with a lot less work.
 
AlphaDogChoppers said:
I went through many steps to achieve that result. Because of the deep gouges, and the badge recess that I wanted to eliminate, I started with 120 grit in an air tool. Did some work with rollock disks and some with flap disks. 120 grit leaves some pretty bad scratches, of course. Then I wet sanded with 220, 320, 600, 800. Each time, not switching to the next grit until all traces of scratches from the previous grit were gone.

Then I finished them off with a buffing wheel on a 6" buffer using an emery bar. Then I switched wheels and did rouge.

The Harbor Freight buffer was not expensive. Without it, I could have never gotten this result. Buffing aluminum to a show polish requires high speed, (at least 3000 rpm,) and enough power to build some heat in the piece. The polishing bars are abrasives in tallow. It takes some heat to melt the tallow and make the abrasive really work. Trying to use a buffing wheel in an electric drill is not very effective because it just doesn't have the speed and power to make it happen.

Do yourself a favor and remove those cases, then you can do a proper job of polishing them with a lot less work.
Your cases look great but I'm not going for a show finish, just something less aged and gnarled. Mirror-polished wouldn't match the rest of my bike. I've done a fair amount of sanding and smoothing, and the right-side cover turned out pretty good with just electric drill buffing and a final hand polish. I need a way to strip the ugly sealer off. This morning I tried a chemical stripper intended for aluminum and it did a fair job. With a second application on some trouble spot it ought to look just about right. I've heard too many near-horror stories about oven cleaner to try it, but thanks for pointing it out. I'll post some pics later.


I never would have expected a fairly simple post to turn into a dogfight session between posters.
 
<<I never would have expected a fairly simple post to turn into a dogfight session between posters.>>

We were just bored. <G>

Sometimes lacquer thinner or acetone will remove that stuff. Don't want to do it inside unless you have really good ventilation.
 
I've seen a few cases done with ScotchBrite pads. If done with a straight back and forth motion in one direction only, it makes a nice brushed finish effect.
 
Some before and after pics.

Before:
cb360-polish1.jpg


After:
cb360-polish2.jpg


Even better:
cb350-polish3.jpg


I'm going to give the right-side case another round after stripping off more clear coat. It already looks a lot better than previously but I know I can do better. I'm going to leave the big scratches/gouges in place. It's part of the bike's no-so-happy history.

I started to take off the left-side cover but didn't want to get any crap into the stator assembly so I bolted it back up.
 
I have never been able to stop there. Polishing is an addiction with me, and I can't seem to stop myself until I get to "show polish." <g>
 
I wouldnt consider that a polished finish. It appears to have been "cleaned". Not knocking it, looks a hell of a lot better than it did when it was dirty. ADC knows what he's talking about when it comes to this. All of his post that have pertained to polishing have been spot on imo.
 
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