Author Topic: Buffing engine cases  (Read 1889 times)

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Offline Dahmaniac

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Buffing engine cases
« on: June 26, 2016, 01:45:12 PM »
Hello! I'm restoring my old 78 cb550k and I can't seem to find a buffing compound for the aluminum cases that doesn't leave scratches. What compounds and buffing methods are popular among yall? Looking to achieve a high luster. Thanks!

Offline mrbreeze

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Re: Buffing engine cases
« Reply #1 on: June 26, 2016, 03:10:46 PM »
Scratches have to be sanded out. You work from a low number to a high number. The more work you put into it...the better the results. I usually start at 400 and progress through 600, 800, 1000, 1500, and finish with a 3000 pad that my son gave me. If you have deep scratches you may have to start at 280 or so.
« Last Edit: June 28, 2016, 09:47:47 AM by mrbreeze »
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Offline mrbreeze

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Re: Buffing engine cases
« Reply #2 on: June 26, 2016, 03:17:48 PM »
After the sanding you can either use the white jeweler's rouge on a buffing wheel or an aluminum polishing compound such as Mothers. I use the Mothers and it looks damn good but I've been reading about the Flitz and may give that a go also. It's supposed to reduce the haze that Mothers seems to leave behind. I also read that water and a bit of corn starch work but haven't tried it yet.
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Offline JetgreenK1

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Re: Buffing engine cases
« Reply #3 on: June 26, 2016, 09:02:30 PM »
I just rebuilt my carbs and used Mother's polish to do the float bowls and slide covers.  Turned out amazing. Just have to buff it really well once you are done. The haze goes away with elbow grease and a nice cotton rag.

Offline mrbreeze

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Re: Buffing engine cases
« Reply #4 on: June 26, 2016, 09:38:20 PM »
Well that explains it.....I was using a mean cotton rag ;D
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Online Stev-o

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Re: Buffing engine cases
« Reply #5 on: June 26, 2016, 09:51:38 PM »
Your polishing the case??
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Offline 70CB750

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Re: Buffing engine cases
« Reply #6 on: June 27, 2016, 05:39:47 AM »
Prokop
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Offline Ericcb750

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Re: Buffing engine cases
« Reply #7 on: June 28, 2016, 06:40:56 AM »
Hey Guys, I've used flitz on mine and that stuff is AMAZING! It does seem to clean up that little film left behind by Mothers and it also leaves a little protective coating on the part after. I never even heard of it until recently and the stuff works amazing...I've never seen it sold in any of the stores , I had to get mine on Amazon.
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Offline greenjeans

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Re: Buffing engine cases
« Reply #8 on: June 28, 2016, 08:27:31 AM »
If you have a buffing wheel all you need is some brown tripoli.    You don't have to sand past 1000 unless you are really going to a crazy perfect show finish.    I routinely do mine with 220 on a palm sander for the deep scratches, followed by a little hand work for the nooks and crannies, then 400, and then straight to the buffer.  You have to get the old clear off.  I used a stiff yellow wheel similar to the one in the link.  I put 2 of them side by side so it ends up being about 1" wide.   They make the buffing very easy and fast.  I find that the cheap cotton spiral sewn wheels load up with debris quicker and don't polish as quickly.  I just polished an alternator cover, trans/shifter cover and clutch cover.  Took under 2 hours.   I'll post some pics later.    My buffer is just and old 3/4 hp craftsman like this:  http://www.sears.com/craftsman-8inch-bench-buffer-21181/p-00921181000P
Nothing special.    Saves soooooo much time over hand polishing.

I finish with a quick hand polish with semi-chrome or BlueMagic on a soft microfiber towel.

http://www.ebay.ca/itm/12-x5-x3-4-arbor-Airway-Buffing-Wheel-Alum-Stiff-Yellow-Buffer-Divine-Bro-USA-/171892660225
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Offline Bankerdanny

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Re: Buffing engine cases
« Reply #9 on: June 28, 2016, 08:43:29 AM »
I start with sandpaper and work my way up to 2000 or even 2500 grit then switch to buffing compound and a final finish with simichrome polish.
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Current: '76 CB750F. Previous:  '75 CB550F, 2007 Yamaha Vino 125 Scooter, '75 Harley FXE Superglide, '77 GL1000, '77 CB550k, '68 Suzuki K10 80, '68 Yamaha YR2, '69 BMW R69S, '71 Honda SL175, '02 Royal Enfield Bullet 500, '89 Yamaha FJ1200

Offline mrbreeze

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Re: Buffing engine cases
« Reply #10 on: June 28, 2016, 09:53:21 AM »
Yeah I forgot to mention removing the clear coat to begin with. I use the citrus based paint stripper that is available in brush on or aerosol. I usually leave it on overnight and then start the sanding process.
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Offline chewbacca5000

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Re: Buffing engine cases
« Reply #11 on: June 28, 2016, 10:03:25 AM »

Offline Johnie

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Re: Buffing engine cases
« Reply #12 on: June 28, 2016, 10:04:28 AM »
I must be pretty lucky as I have never had to use any sandpaper. I have a 6 inch Craftsman bench buffer I use. You need to get the alumimun hot to let it flow a little when you are buffing. A drill will just not generate that much heat. The first thing you should do is use a chemical stripper to remove the clear. The red brown rouge (depending on your eyesight) will take it off, but it does take a while. It is much easier if you let the stripper get it off for you. But go ahead and experiment with it. The red / brown rouge is a rougher system which will cut faster and deeper. The green rouge will take out the marks from the red. The white will take out the finer marks from the green and give you a nice look. When done some guys clear it again, but I never clear as I want to be able to touch it up whenever I feel like it. However, I have never had to touch it up with the wheel. I just use Semichrome or MAAS polish to make it look great again. A caution for you, use safety glasses and a dust mask as it is dirty work. Plus, a good thick work glove as the aluminum gets hot. Take your time and let the rouge do the work. Use one color rouge per wheel. Do not use the red wheel with green rouge. You do not want to cross contaminate the buffing wheels. When done clean it good and use a black marker to color in the black badge on the stator cover.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

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Offline Ericcb750

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Re: Buffing engine cases
« Reply #13 on: June 28, 2016, 11:24:20 AM »
WOW, I gotta get up my Polishing skills. I have a wheel that i've been practicing with. It's just a 3/4 hp one from Harbor frieght...kind of cheap... but has a nice stand which helps. My first one i did by hand and my arm almost fell off from the elbow down..

I got an alt cover from Kyle (chewbacca) and man does that thing look like a mirror... i use it to do my hair in the morning..ha-ha.. Very nice work.
1978 CB750K
1978 CB750F super sport
2005 Sportster 1208

Offline Johnie

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Re: Buffing engine cases
« Reply #14 on: June 28, 2016, 01:29:43 PM »
I would have to say that the polishing is my least favorite task :)
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline chewbacca5000

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Re: Buffing engine cases
« Reply #15 on: June 28, 2016, 02:42:36 PM »
I would have to say that the polishing is my least favorite task :)

Really?  What about wheels bearings?  Or cutting the bushings out of a swing arm.

Offline greenjeans

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Re: Buffing engine cases
« Reply #16 on: June 28, 2016, 02:50:12 PM »
I'd rather do bearings than polish.  Takes less time. ;)
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Offline Johnie

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Re: Buffing engine cases
« Reply #17 on: June 28, 2016, 05:25:35 PM »
Yah, wheel bearings is easy. Polishing so time consuming to get a good job done. I think I am just to fussy.
1970 CB750K0 - Candy Ruby Red
1973 CB750K3 - Candy Bacchus Olive or Sunflake Orange
1970 Chevy Chevelle SS396 - Cortez Silver
1976 GL1000 Sulphur Yellow

Oshkosh, WI  USA

Offline jonda500

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Re: Buffing engine cases
« Reply #18 on: June 28, 2016, 05:45:15 PM »
I'd so much rather do some polishing than pull out my carbs yet again! Polishing is fairly mindless so my brain can be off in fairyland rather than worrying about whether I've left a part out or put it in backwards, etc...
John
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Offline przjohn

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Re: Buffing engine cases
« Reply #19 on: June 28, 2016, 05:57:42 PM »
swmetal.com

The definitive source for your polishing questions. They have everything you need including answers.
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Offline mrbreeze

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Re: Buffing engine cases
« Reply #20 on: June 28, 2016, 11:15:22 PM »
swmetal.com

The definitive source for your polishing questions. They have everything you need including answers.
I don't recall seeing these guys in my search for aluminum polishing awhile back but they are in my favorites now.
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