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Thread: Suggestions....

  1. #1
    Registered User Jinxman69's Avatar
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    Suggestions....

    What are some opinions on coating aluminum parts after they are bead and soda blasted to slow/prevent oxidation. Whether I should at all... Thanks

  2. #2
    Registered User lmo1131's Avatar
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    Are you talking cast aluminum engine parts, or forged aluminum parts?

    Bead/soda blasting will not "slow" oxidation, it just removes it. "Oxidation" is actually a protectant in and of itself, albeit, not very attractive. I think the general approach is to clean them up, and let them naturally "age" with an occasional spritz of WD40 or something similar.

    If you were referring to forged parts, i.e. triple clamps, rear brake lever, etc. you could have them clear anodized. But why bother?
    "It is what you discover, after you know it all, that counts." _ John Wooden
    Lew Morris
    1973 R75/5 - original owner
    1963 Dnepr

  3. #3
    Liaison 20774's Avatar
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    I think what he meant to say was "What are some opinions on coating aluminum parts to slow/prevent oxidation after they are bead and soda blasted. Kind of changes the meaning a bit.

    IMO, things are just going to get dirty and unless you want a life of constant cleaning, it's just a fact of life. It also depends on where you're living. Right on the beach...then you probably do need to wash pretty frequently. Even places where there's left over road salt if you're riding on the fringe of winter...still needs frequent washes.

    To coin the phrase about restorations, "they're only clean once"!
    Kurt -- Forum Liaison ---> Resources and Links Thread <---
    '78 R100/7 & '69 R69S & '52 R25/2
    mine-ineye-deatheah-pielayah-jooa-kalayus. oolah-minane-hay-meeriah-kal-oyus-algay-a-thaykin', buddy!

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    My understanding of the rough castings finish on our airheads is that they disrupt the air flowing past them and provide air cooling. If you coat or plate these surfaces, your air cooling efficiency is diminished. For that reason, I wouldn't. Keeping them clean is probably the best way to keep the oxidation and corrosion from being a problem. I do a lot of riding, including 140 miles yesterday in the mountains of central ID, but take a moment to clean every now and then. The attached images are of my '83 R80ST, which I unpacked and setup at the dealer in November of '83. I've ridden it for thirty plus years and 130,000+ miles, and have never used anything other than degreaser, or dish soap to maintain the patina. Ride easy and the best to you in the New Year!
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    Gary Phillips - #6322
    Wildland Firefighter, Retired, Riggins, ID
    Heartland Moto Locos BMW Riders
    '77 R100/7 Dirt Hack, '83 R80ST, '85 K100RS w/EML, '00 R1100RS

  5. #5
    Airmarshal-IL James.A's Avatar
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    Quote Originally Posted by Jinxman69 View Post
    What are some opinions on coating aluminum parts after they are bead and soda blasted to slow/prevent oxidation. Whether I should at all... Thanks
    I know some riders of a variety of classic bikes (mostly British) who use high grade aluminum paint on the cast bits. If the parts are squeaky clean, the result is very good to the point of "can't hardly tell the difference". I, personally, would never bother with this sort of thing. I detail my bikes once every 5 years or so.

  6. #6
    Rally Rat
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    I question weather the painting may effect the cooling properties of the aluminum that is painted. This is sort of preventative maintenance.Each person seems to do different things to keep their airheads looking good. I s100 the engine every couple years and wipe it down with clean rags ,then I use a whole can of silicone spray wetting the whole engine and then blow off the excess with air , and then the engine gets wiped down again .That's all I do and when I do wash the bike I use turtle wax car wash and the dirt and grime rinses right off. I never heard any bad things about using silicone As a protectant/sealant. I do know that silicone can screw up paint in so much as it has to be all removed if you were to paint those parts to get the paint to adhere properly .Most have their little things they do to keep their bikes looking good ,how much time do you have to spend on it ??

  7. #7
    Registered User lmo1131's Avatar
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    My understanding of the rough castings finish on our airheads is that they disrupt the air flowing past them and provide air cooling.
    Oh, i dunno. Have you ever noticed the dust on your car before you drive somewhere, and then notice it again when you get to your destination? "Boundary layer" is why it doesn't get blown off. I would hazard a guess that the relatively rough surface of the cast aluminum doesn't effect the airflow, at all.

    The radiating heat from the engine isn't a "physical" thing (in the sense that dust is) and is different in that it's leaving the surface (radiating) and being carried away by the airstream. Painting that surface, while it might slow down the radiation process, doesn't stop it.
    "It is what you discover, after you know it all, that counts." _ John Wooden
    Lew Morris
    1973 R75/5 - original owner
    1963 Dnepr

  8. #8
    Quote Originally Posted by Jinxman69 View Post
    What are some opinions on coating aluminum parts after they are bead and soda blasted to slow/prevent oxidation. Whether I should at all... Thanks
    Those nice pictures posted above by Gary Phillips are one side of the coin. I've always thought that the best way to get a nice vintage bike is to buy a new one you like, care for it over time, and grow old gracefully with it. However, the other side of the coin is to drag home something that looks like this:



    After a lot of time and effort to get it clean, it is tempting to use some kind of clearcoat to keep it looking nice. I don't believe in that. There are some very high quality clearcoat materials available today, but I think eventually they will all have a problem. If the alloy starts to look nasty under the clearcoat, it is a lot more trouble to strip off the coating and then clean and polish than it would be to simply keep up the bare surface with routine cleaning. Once the neglect and "white rust" are cleaned away, it should be easy enough to maintain.

    Autosol has a protective spray that seems promising, but I don't have any long term experience with it yet. At least it isn't something difficult to remove. I've started using their products and like them.

    By the way, the thing I have found that works best for the mess in my picture above is something I laughed at when I first saw it recommended. That is WD-40 and brass bristled brushes. I found out that it works amazingly well and is about as cheap a method as you will find. To reduce the necessary elbow grease, I also like brass cup brushes from Forney used at slow speed in my Dremel tool. Rotary brass brushes by themselves will color your alloy with a yellow/gold tint. But -- if the rotary brass brush is kept wet with a bit of WD-40, that won't happen. Ditto if the brush is used with a small amount of Mother's Metal Polish or Autosol Metal Polish Paste. I scrub till there's a lot of black crud on the surface, wipe with a cheap paper towel and repeat till no more black stuff scrubs up. Then I give it a light spray of WD-40 and scrub some more with just the paper towel. Autosol also makes a spray cleaner, but I have found that WD-40 works as well and is cheaper to use.

    So, I probably have my alloy shinier than most would like, but I figure it will dull out with use and exposure. It's all a learning process, and look what I had to start with.



    I will 'fess up and say that after I got my alloy parts scrupulously clean, I hit them with some silver Rub 'n Buff to get the color the same on all the pieces of the engine housing. However, like the Autosol Protective Oil, the Rub 'n Buff is easy to remove if you want the bare alloy back.

    HTH

    Ray
    Last edited by fxray; 10-31-2017 at 03:29 AM. Reason: Repaired picture links destroyed by pee-bucket

  9. #9
    Registered User katcon85's Avatar
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    I "renewed" my R75/6 last winter and spent A LOT of time and elbow grease cleaning oxidation off of the engine cover, gear box, air box etc etc. I also sent the heads out for a top end job by Tom Cutter. He recommends Boeshield T-9 developed by Boeing Aircraft corp- it's a spray on protectant film/oil for aluminum and steel. I use it on all my cast aluminum including the wheel hubs. It repels water for a while, but it does wear/wash off after a while.
    I usually give the bike a serious wash in the winter when I'm doing all the annual stuff and apply the T9 and wax the painted parts. Then late in the summer, or if I've been riding in the rain a lot and the bike is mucky- I'll wash it again and re-apply the T9. I'm assuming that since I had newly blasted and cleaned aluminum, that the pores were really open. I'm hoping that after a couple of years of maintenance and regular application, the aluminum will build up a protective layer that hopefully closes the 'pores'.

    Kat
    1974 R75/6

  10. #10
    Registered User 80092's Avatar
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    Quote Originally Posted by fxray View Post
    Those nice pictures posted above by Gary Phillips are one side of the coin. I've always thought that the best way to get a nice vintage bike is to buy a new one you like, care for it over time, and grow old gracefully with it. However, the other side of the coin is to drag home something that looks like this:



    After a lot of time and effort to get it clean, it is tempting to use some kind of clearcoat to keep it looking nice. I don't believe in that. There are some very high quality clearcoat materials available today, but I think eventually they will all have a problem. If the alloy starts to look nasty under the clearcoat, it is a lot more trouble to strip off the coating and then clean and polish than it would be to simply keep up the bare surface with routine cleaning. Once the neglect and "white rust" are cleaned away, it should be easy enough to maintain.

    Autosol has a protective spray that seems promising, but I don't have any long term experience with it yet. At least it isn't something difficult to remove. I've started using their products and like them.

    By the way, the thing I have found that works best for the mess in my picture above is something I laughed at when I first saw it recommended. That is WD-40 and brass bristled brushes. I found out that it works amazingly well and is about as cheap a method as you will find. To reduce the necessary elbow grease, I also like brass cup brushes from Forney used at slow speed in my Dremel tool. Rotary brass brushes by themselves will color your alloy with a yellow/gold tint. But -- if the rotary brass brush is kept wet with a bit of WD-40, that won't happen. Ditto if the brush is used with a small amount of Mother's Metal Polish or Autosol Metal Polish Paste. I scrub till there's a lot of black crud on the surface, wipe with a cheap paper towel and repeat till no more black stuff scrubs up. Then I give it a light spray of WD-40 and scrub some more with just the paper towel. Autosol also makes a spray cleaner, but I have found that WD-40 works as well and is cheaper to use.

    So, I probably have my alloy shinier than most would like, but I figure it will dull out with use and exposure. It's all a learning process, and look what I had to start with.



    I will 'fess up and say that after I got my alloy parts scrupulously clean, I hit them with some silver Rub 'n Buff to get the color the same on all the pieces of the engine housing. However, like the Autosol Protective Oil, the Rub 'n Buff is easy to remove if you want the bare alloy back.

    HTH

    Ray
    Ray great job, any pictures of your other aluminum parts you have cleaned with this method ?

    Thanks
    Peter Murray
    Stroudsburg, Pa.
    IBA 359
    2014 RTW, 73 R75/5

  11. #11
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    Didn't read all of thread, but my solution was fine steel wool and WD-40 with lots of elbow "grease".
    MOA #46783

  12. #12
    Quote Originally Posted by 80092 View Post
    Ray great job, any pictures of your other aluminum parts you have cleaned with this method ?

    Thanks
    Yes, but this is drifting away from the OP's question about preserving the finish once it is clean. I kind of gave my opinion on that earlier. I think once it is clean, routine maintenance will keep it up if there is no clear coat or paint applied. Here's what it looks like if it sits in a barn with no routine maintenance:



    It had corroded to the point where it had white flakes on top of the battleship gray. Wherever one of those bits of "white rust" occurs, it'll almost brush off, but will leave a spot that is hard to get rid of completely.

    I experimented with several different cleaners/polishes, including Simple Green, Zep Brightener, Zephyr Metal Polish, Mother's Metal Polish, Autosol Cleaner, Autosol Metal Polish. I tried several different tools, including Scotch-Brite, brass bristled hand brushes, toothbrushes, small cloth "mops" of different sizes (some in my electric drill, some in my Dremel Tool).

    I stayed away from steel wool because various people on the internet advised against it. Yet, as Motodan just said, it worked well for him. I think the fear is that small bits of the wool get imbedded in the alloy and later cause rust streaks. I have my doubts, but I still didn't try it.

    In the end, what seemed to work best for me with the least elbow grease was the little round brass cup brushes in my Dremel, used with WD-40 (see links in my earlier post). These brushes are small enough to clean in the tighter areas, but do well out on the bigger surfaces too. On a high rpm, the brush almost flattens out, and tends to lose bristles. That is messy and the brush won't last long that way. I was using them at low speed with the surface having just a little WD-40 on it. The brush will last quite a while if used that way. I scrubbed a small area till it had a lot of black grunge floating up in the WD-40 film. Then I wiped it good with paper towels, and did it again. I repeated this till the black grunge quit showing up. I went through lots of paper towels, but less than one can of WD-40.

    When I thought I had it cleaned, I rubbed in a tiny bit of Silver Rub 'n Buff. I think their Pewter color is a better match for what most people think the BMW alloy should be, but I used what I could find without too much trouble.

    Here are some pictures of where it is now:







    And the transmission:







    So far, the cylinders, heads, and valve covers have just been along for the ride. I left them in place while I was cleaning the crankcase, just to make sure I didn't get crud inside the engine.

    I have tried some cleaning on the cylinders. To get to the bottom of the fins, I was trying things like a 22 cal gun cleaning brush, with WD-40, or a paint-stirring stick with some Scotch-brite pad attached. This would work, but might take slightly longer than forever.

    So, this is where I likely will depart from what I said earlier about clearcoat and paint. I plan to pull them off and disassemble them. Then I will put them back together as an "empty sandwich" and make something to seal off the bottom of the cylinder spigot and PRT bores. Then I will bead blast them and most likely paint the cylinders with some high temp Duplicolor Engine Enamel with Ceramic. I am leaning toward their DE1650 Cast Coat Aluminum, but am not sure yet. I have used their paint on an engine before and been pleased with the results.

    Note: I only bead blast engine components as a last resort and then do it as carefully as I can. I am aware of what just a few stray bits of glass can do to an engine, but I think there are ways to get around the danger. I would soda blast instead, except that would not be conducive to painting if that's what I decide to do.

    Yikes, sorry this is so long. I got carried away.

    Ray
    Last edited by fxray; 10-31-2017 at 03:27 AM. Reason: Repaired picture links destroyed by pee-bucket

  13. #13
    The problem, IMO is that "clean" shouldn't mean "shiny" aluminum look. The original was a "clean" aluminum, but not shiny.
    "The difference between death and taxes is that death doesn't change every time congress meets." - Will Rogers

  14. #14
    I agree with you. What I showed in the pictures above will be objectionable to a lot of people. I struggled to find some kind of balance in cleaning up my engine. Areas that were covered with grease or oil cleaned up pretty well and left the original color of the alloy. Same for inside, like under the starter cover for example. Other areas out in the open were more deeply oxidized and more difficult to clean. Almost any metal polish is going to impart a metallic shine that leans more toward chrome than toward the dull white of aluminum oxide. Different parts of the engine evidently have different alloy mixtures and therefore different colors when clean. I just didn't care for the look, but I am new to BMW. I'm still waiting for the look to grow on me.

    I know that some prefer their engines to be gray, but clean, as opposed to shiny. Others have achieved that matte white that seems desirable. I decided that for me, I'll let it shine up at the beginning and see what develops, since that was the way I could get it all fairly uniform.

    It's kind of the same thing with British bikes, where a lot of people prefer the look of bead blasted alloy. IMHO, that is because over the past 30 to 40 yrs, that is what they have become accustomed to seeing. However, looking inside the engine shows what the alloy looked like if it was protected since it was new. It was not a slightly rough, matte gray. My Triumph engine is probably too shiny for some people too, but I like it.

    As far as paint goes, I seem to be talking out of both sides of my mouth in the earlier posts. I don't like paint on the engine, but am probably going to paint the jugs. That's because I suspect that without paint, they will turn dark gray again in a short time. The fins are deeper than I want to mess with for routine maintenance. The rest of the engine should be easy enough to keep clean.

    I guess it all comes down to personal choice.

    Ray
    Last edited by fxray; 10-31-2017 at 03:30 AM.

  15. #15
    I happened onto this thread from 11/2015, so nearly 2 yrs ago now, and noticed that I had a lot of broken pee-bucket picture links. In the process of replacing them, I see that I was showing some in-process pictures on the alloy parts of my '74 R90/6. I did eventually get that bike on the road. Here is the bike after I got it running earlier this year (5/2017).



    Back in 2015, we were discussing clean versus shiny.

    Quote Originally Posted by SCBuckeye View Post
    The problem, IMO is that "clean" shouldn't mean "shiny" aluminum look. The original was a "clean" aluminum, but not shiny.
    This may be a little on the shiny side, but I like it anyway. I rode it about 8,000 miles this summer, without really going anywhere in particular, and the shiny is starting to mellow out.

    Ray

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