Clear Coat over a polished Aluminum Tank

Hi all I have just re-polished my Evan Wilcox tank on my production racer replica and was wondering if anybody has experience with a clear coat that doesn't yellow ands retains the shine. The decals obviously go on after the polish which makes re-polishing around the decals almost impossible so I was thinking I might clearcoat. thanks

I have had a polished tank on mine for years. I have never coated it. I think you would have peeling issues. Aluminum likes to be scuffed just before painting in order to get it to adhere. Defeats the polishing…

I just give it a quick polish maybe twice a year. Takes 10 minutes, and is very rewarding.

I've seen clear over decals that didn't go well; the decals wrinkled. Don't know if it was materials or a process issue.

Derek Wilson said:

Aluminum likes to be scuffed just before painting in order to get it to adhere. Defeats the polishing…

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I agree. I've never had good luck coating polished metal.

What Maylar said. I have tried various clear coat offerings including clear powder coat on a wide variety of aluminum engine parts.
They always, sooner or later yellowed. Heat and cold cycle, aging, long exposure to sun and O2 etc. etc,...they always yellowed.
The real PITA is removing the clear coat after it has yellowed. I would usually end up vapor blasting just to get it back to an honest/clean surface.

So, clearcoat is probably yellowing on top of paint too. May explain why it's so difficult to match colours.

At the local Norton club, one owner has a fastback with a polished alloy tank. It looks superb. Worth the extra effort, if you don't mind polishing around the tank decals.

You’ve got the added challenge of petrol too.

A polished surface and no etch primer means this is always gonna be a challenge. Add in petrols ability to lift and peel paint, especially around the filler neck area, and I reckon you’re gonna struggle to find something suitable.

Longtimegone said:

I've seen clear over decals that didn't go well; the decals wrinkled. Don't know if it was materials or a process issue.

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it's both the material and the process - rule of thumb -- enamel, including 2K clears over decals - yes, lacquer over decals - NO, NO, NO!!! process - i've found this works best for me - light or tack coat first, then medium coat, before a wet coat. normal flash times.

to jms's original question - clear over anything polished is always a challenge. what i would PERSONALLY do on a polished aluminum surface. prior to anything, clean the surface, i mean squeaky clean. i would use a water based cleaner, carefully around the decals and a light prep-sol clean avoiding the decals. use a clean microfiber cloth. i would use a quality, high solids 2K clear - first coat would be a very light coat also referred to as a tack coat, followed with a medium wet coat, and after a normal flash times, follow with several wet coats. depending on your surface-to-decal transition preference, number of coats, cut and buff, etc, will dictate the total number of clear coats applied. IMO, a quality, high solids 2K clear will give you the best fuel resistant, non-yellowing finish you can get. again, this is personally what i would do. some folks may have better methods on how to approach the task.

Longtimegone said:

I've seen clear over decals that didn't go well; the decals wrinkled. Don't know if it was materials or a process issue.

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Water-slide decals will wrinkle under most any solvent based paint, though I've not tried enamel. I painted this Indian for a paying customer and went through a bunch of decals ($$) before finally getting vinyl decals made by a local sign maker.



Vinyl is a challenge too, however, as the clear can bridge at the edges and leave air bubbles that will crack and peel if you apply it too thickly.

jms said:

Hi all I have just re-polished my Evan Wilcox tank on my production racer replica and was wondering if anybody has experience with a clear coat that doesn't yellow ands retains the shine. The decals obviously go on after the polish which makes re-polishing around the decals almost impossible so I was thinking I might clearcoat. thanks

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Use Shine Seal ( formerly known as Zoop Seal ) - a chemical sealer you simply wipe on and polish out by hand rubbing . Expensive but it really works . I am the world’s biggest skeptic when it comes to stuff like this but it does what it claims . This is my ES2 years after application and I live at the seashore in the northeast USA , the corrosion capital of the universe .


Clear finish over polished metal has the potential to get ugly if moisture gets between the finish and the metal surface - take a look at aluminum wheels on modern cars after a few years .

Hinckley Triumph manages to clear coat their polished alloy spoked rims on the Thruxton 1200.
I don't know what process they have used but the result is very good, easy to clean and , of course, shouldnt ever need to polish.

Glen

worntorn said:

Hinckley Triumph manages to clear coat their polished alloy spoked rims on the Thruxton 1200.
I don't know what process they have used but the result is very good, easy to clean and , of course, shouldnt ever need to polish.

Glen

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I would guess that’s clear powder coat ?

I thought about clear powder coat earlier cos it is just as tough as any powder coat I believe.

I don’t think it gives a totally unaffected shine vs a bare polished surface though.

I don’t know if a tank could be powder coated?

It‘d be a brave man who did though… goodness knows how you‘d remove it if you so wished ?

I'm not that brave, still polishing the bare alloy.
The Triumph wheels look nice to my eye but as you say, there is some effect from the clear coat. Mainly it is not quite as shiny as freshly polished bare alloy. It does make the wheels easy keep.

I spend quite a bit of time fussing on the bikes that have bare alloy rims. At that they only really look good for a little while after polish.





Glen

As stated above , clear finish over polished metal can get ugly .
Here are the clear coated aluminum toolboxes on my truck - what you see is not on the surface but between the finish and the metal.

And an extreme example - the clear coated wheels on my 2007 Honda Element - Honda replaced these wheels in 2009 because of the trapped corrosion issues but it is futile .

Obviously I don’t recommend clear coat . You will be better off doing nothing .

I like those granite wheels!

Glen

worntorn said:

Hinckley Triumph manages to clear coat their polished alloy spoked rims on the Thruxton 1200.
I don't know what process they have used but the result is very good, easy to clean and , of course, shouldnt ever need to polish.

Glen

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I'm pleased you've had good luck with the finish on yours
In the UK the finish can be a problem with hinkley triumphs and Bonnevilles particularly especially of you ride all year round
A few of my mates own them and the wheels particularly suffer
Also the powder coating off the engine
My mates engine number fell completely off ,it's just a shard of powder coat in envelop now incase he sells the bike

There's no powder coating on my engine. Triumph explains in the owners manual that it is bare alloy and has to be cared for the same as bikes from days gone by.
Modern Triumph owners as a lot are not terribly capable from what I've seen.
For some this bit of simple maintenance is overwhelming.
One YouTuber whined excessively about salt damage on the bare alloy ( that he did not protect)
Triumph actually gave him a new timing cover just to shut him up.
I would not want to be in the new bike business today.

Glen

worntorn said:

There's no powder coating on my engine. Triumph explains in the owners manual that it is bare alloy and has to be cared for the same as bikes from days gone by.
Modern Triumph owners as a lot are not terribly capable from what I've seen.
For some this bit of simple maintenance is overwhelming.
One YouTuber whined excessively about salt damage on the bare alloy ( that he did not protect)
Triumph actually gave him a new timing cover just to shut him up.
I would not want to be in the new bike business today.

Glen

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You’re bang on there, and it’s not limited to Triumph owners. I know a fella who was whining about the poor quality of his new Royal Enfield until I pointed out the exact same point…it’s bare alloy… you rode it through winter… you failed to protect or clean it (despite being told)… DUH…

Fast Eddie said:

You’re bang on there, and it’s not limited to Triumph owners. I know a fella who was whining about the poor quality of his new Royal Enfield until I pointed out the exact same point…it’s bare alloy… you rode it through winter… you failed to protect or clean it (despite being told)… DUH…

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This winter, I used ACF on my Norton and Enfield. A couple of weeks ago, I cleaned both off and polished. The Norton looks like new. The Enfield now has a cloudy look to it. Maybe more porous. Not all alloys are the same.

Mart UK said:

This winter, I used ACF on my Norton and Enfield. A couple of weeks ago, I cleaned both off and polished. The Norton looks like new. The Enfield now has a cloudy look to it. Maybe more porous. Not all alloys are the same.

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Fair point. But my mates doesn’t look cloudy… it looks like it’s been recovered from a shipwreck !!
The best alloy in the world is still gonna corrode in salt if unprotected…