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Discussion Starter #1
When next I have a good idea I pray that the universe, it's infinite wisdom, beats me with a cricket bat until it goes away.

I'm working with an 1150 BMW. The paint scheme is black and until recently so was the rest of the bike, engine, swingarm, para-lever, telelever, , forks (you get the idea). I thought it would be truer to a more retro aesthetic if the alloy parts of the bike we polished.

Note to self: If you don't polish metal for a living and don't have a polishing rig...this is a truly enormous and massively labour intensive job. I am mostly happy with the results but yea gods the time it takes. I don't know what BMW cat their alloy with but paint stripper and soaking in enamel thinners doesn't take it off cleanly. You could use this tuff to line nuclear reactors. Bottom line, mechanical stripping is the only reliable method.

Has anyone used a product from POR15 to clear coat their alloy. It's a two part epoxy, fuel resistant, operating temperature up to about 160 Celsius and gets a good report from the hot-rodding community.. but it costs not cheap.

I know it will reduce the shine and you have to be SUPER careful with the alloy prep they suggest. Straight from the bottle and applied for as longe as they suggest and your lovingly polished alloy parts get dull milky white marks. Dilution, a shorter application time and lots of water to wash it off is a solution.

The general consensus on this forum is polish it, don't coat it and own the fact that it will need cleaning every now and then with metal polish. My question is has anyone used this stuff and if so what was their experience? Some pics below of the sort of things I was considering it for.

Rear swing-arm (not completely finished)


Wheel set I'm putting together, thought a silver edge would look good. (setting them up for tubeless)


Monza fuel cap conversion (and yes it does lock and still uses all of the original BMW mechanism)
 

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When next I have a good idea I pray that the universe, it's infinite wisdom, beats me with a cricket bat until it goes away.

I'm working with an 1150 BMW. The paint scheme is black and until recently so was the rest of the bike, engine, swingarm, para-lever, telelever, , forks (you get the idea). I thought it would be truer to a more retro aesthetic if the alloy parts of the bike we polished.

Note to self: If you don't polish metal for a living and don't have a polishing rig...this is a truly enormous and massively labour intensive job. I am mostly happy with the results but yea gods the time it takes. I don't know what BMW cat their alloy with but paint stripper and soaking in enamel thinners doesn't take it off cleanly. You could use this tuff to line nuclear reactors. Bottom line, mechanical stripping is the only reliable method.

Has anyone used a product from POR15 to clear coat their alloy. It's a two part epoxy, fuel resistant, operating temperature up to about 160 Celsius and gets a good report from the hot-rodding community.. but it costs not cheap.

I know it will reduce the shine and you have to be SUPER careful with the alloy prep they suggest. Straight from the bottle and applied for as longe as they suggest and your lovingly polished alloy parts get dull milky white marks. Dilution, a shorter application time and lots of water to wash it off is a solution.

The general consensus on this forum is polish it, don't coat it and own the fact that it will need cleaning every now and then with metal polish. My question is has anyone used this stuff and if so what was their experience? Some pics below of the sort of things I was considering it for.

Rear swing-arm (not completely finished)


Wheel set I'm putting together, thought a silver edge would look good. (setting them up for tubeless)


Monza fuel cap conversion (and yes it does lock and still uses all of the original BMW mechanism)
I have seen it used on vintage race cars. All I can tell you is after looking at the quality of your workmanship I'm willing to be it's not what you are looking for. Many of the Japanese companies clear coat their ally bits that have been polished and even that doesn't last forever. Again looking at how good your stuff looks................was the heck out of it and then just keep after it. Will be a we bit of work but not crazy. I have a Hinkley Triumph do up as a '60's Cafe Racer and the ally bits are all polished. It was I bitch getting the clear (I used Aircraft paint remover from Aircraft Spruce) off and a little elbow grease to do the polish but that was 10 years ago and it still looks pretty good. This said I ride the bike a lot and it is no where a shinny as your bits but I only spif it up about every 6 months.
Cheers
 

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Weren't those parts all originally clear anodized? I think you polished off any anodize coating, you might want to look at replacing that with the same or something similar to seal the metal from corrosion. It's oxidation and corrosion that will dull and discolour the finish.
 

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Discussion Starter #4
You are correct I did polish off the coating material, that was my intention. The previous coating did not have the degree of lustre I was seeking for the parts.

The coating material used by BMW is a dual process product that has a thick undercoat and a surface coating that can be silverfish, black or dark metallic blue black in colour. None of the parts in that post were clear anodised and I won't be having them anodised. All of the parts in question are castings with the exception of the wheel rims.

Anodising is not a reliable surface treatment for cast parts for the following reasons:
  1. The alloys used for casting commonly contain elements (commonly silicon) to improve flow and assist the casting process. I recognise that designated 200 series alloys do not, but I cannot make that identification by visual inspection. Surface impurities particularly silicon have a significant deleterious effect on the quality of anodised parts making the process "hit and miss" when used on castings. They will smut unevenly and the film will not be clear and even raging from grey to black.
  2. The swing arm is cast and welded. This means that all of the alloy casting issues will be magnified because of the addition of issues such as cold mappings, gas marks and the sand holes etc.
Some companies will claim to be able to anodise cast parts but the issue is reliability. The success of the process cannot be guaranteed and if it fails the entire part requires re-polishing. In addition the higher levels interstitial porosity and inclusions in cast parts can lead to weakening of the parts if they are anodised.

You are "on the money" that moisture and oxygen will create further oxidisation on the surface of polished aluminium. The application of high temperature waxes (e.g BWM101 etc) can help to reduce that effect but cleaning will still be needed (re-polishing) if I leave the material uncoated.

Since anodising is an undesirable option for these parts, my intent was to see if:
  1. anyone had used the POR 15 product which is a dual part epoxy paint suitable for application using a spray gun, or
  2. should I accept that the parts will need maintenance and leave them uncoated.
Sol
 

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Can't help you with those products, I've always just used a bead blaster and had the aluminum clear anodized or applied tung oil over painted aluminum cast parts like rims to better seal the finish.

That rim does look a lot nicer with the bare metal showing, never been a huge fan of black rims :cool:
 

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Um, did you notice the part where it says "POR-15 Rust Preventive Coating is sensitive to UV light and must be top coated when prolonged exposure to sunlight is possible."
 

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Discussion Starter #7
That would indeed be an issue if I was considering their rust preventative coating.

My enquiry is about their clear coat product.

POR 15 describe it as:
A high gloss, water-clear topcoat designed for spray or brush application over all metal surfaces, including highly polished aluminum and chrome surfaces. Glisten PC is a high solids moisture curing urethanes that offers superior performance in adhesion, corrosion protection, flexibility and UV stability.
 

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You failed to mention "Glisten PC" previously, I googled that and came up with a totally different product & packaging.
:/ not finding anything that claims it does what you want it to do, maybe you can post a link to the actual product because all I am finding is paint and clear paint.

Superior performance UV resistant and superior UV stability does not equate to impervious, it is relative comparison to other urethane coatings. I think you are falling advertising hype. Take a look at the customer product reviews.
 

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I have simply used regular 2k clear coat over polished alloy before with good results.
Spraying without getting runs is the main issue i found.

I have never had a problem with adhesion or yellowing doing this even on engine cases.
 

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Discussion Starter #10
If I go ahead with clear coat my plan was to:
  1. Degrease the parts with wax and grease remover.
  2. Degrease again with Automotive thinner
  3. Wash the parts with detergent
  4. Rinse, Rinse, Rinse
  5. Spray the parts with 50% alloy adhesion promoter for 30 secs.
  6. Rinse with tap water a couple of times then demineralised water
  7. Dry (clean new microfibre cloth)
  8. Alloy to air dry for a day
  9. Apply the coating with a spray gun. Depending on the where the part is located 2-3 coats.
  10. Re-application time is two hours (annoying because it sets before that and I will have to remix a new pot each time)
  11. Leave two weeks
  12. Polish with a fine automotive polish
  13. Wax with FinishKare BWM 101 high temperature wax paste
  14. Strap new born infants to the part during re-installation.
Is there anything else relevant that you may done that you would add.

If that degree of surface prep seems overkill. I don't mind. The final polish on some of these parts used red jewellers rouge, the same stuff they use on gold rings. It has taken a lot of time and the job isn't done. I want any surface coating done right and done once. The aim is to do the build so that it looks like a late build BMW factory concept/prototype and I have the luxury of time and a partner who is patient enough to put up with motorcycle parts on the dining table.

Sol
 

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You do a far more thorough job than me.

I usually clean thoroughly with 2k thinners.
Then spray a very light mist coat initially then build up from there.
Your method above seems pretty good to be honest, almost too good.

If you don't want to do it yourself i would just send it off to be clear anodised.
Check out this polished and clear anodised bicycle frame
 

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