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Old 09-13-05, 03:05 PM   #1
Batavus
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powder coat supposed to scratch this easily?

Hi,

I recently had an old steel Peugeot powdercoated black. The finish is great, but this week my bike fell over against one of my other bikes and hit its chainring (no chain). Now the top tube has a big scratch down to the metal. I also noticed that the coat itself was very thin, like the guy who did the job wanted to save on powder or something. Will try to post pics if it's any help. I was so pi**ed off, but hey my stupid mistake, because i dropped it myself.

But isn't powdercoat supposed to be 'bombproof'? I know if you try hard enough you can damage anything, but the bike just toppled over slowly and unfortunately hit the sharp teeth of the chainring.
So much for the powdercoat myth then...
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Old 09-13-05, 04:31 PM   #2
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Hit something sharp enough hard enough and you can chip or scratch ANY finish. Powder coating is tough but not bulletproof.
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Old 09-13-05, 09:33 PM   #3
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Powdercoat is more tough than hard, scraping a chainring with any force would test any finish.

The thickness of the coating is a comprimise eg; thicker the coat the more orange peel or rippled the finish.
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Old 09-13-05, 09:42 PM   #4
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Powdercoating is pretty sucky unless you get a clearcoat too. I have one bike thats clearcoated and ones thats not... on the one that is, its been in several bad road wrecks and still looks new. The non coated one looked pretty beat after just commuting on campus for a month.
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Old 09-14-05, 01:59 AM   #5
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Powdercoating really refers to the method the finish is applied. Rather than using solvents that evaporate away like paint, the pigments and binders in powdercoating are applied dry. Then the binders are melted together and flowed with heat. The resultant coating is very, very similar to paint at the molecular level. It will scratch and chip just like paint.
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Old 09-14-05, 07:23 AM   #6
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Quote:
Originally Posted by DannoXYZ
Powdercoating really refers to the method the finish is applied. Rather than using solvents that evaporate away like paint, the pigments and binders in powdercoating are applied dry. Then the binders are melted together and flowed with heat. The resultant coating is very, very similar to paint at the molecular level. It will scratch and chip just like paint.
Properly done powdercoat is tougher than regular paint. It's commonly used for automotive parts, like pickup truck bumpers, since it's so durable to abrasion. It's also great against corrosion; longer salt spray protection without special undercoats. And speaking of undercoats, powdercoat does not require any; the powder is sprayed directly on top of the bare metal. In this respect it is quite a bit different from regular paint which requires a primer coat to stick to the metal.
There are different types of powdercoat, urethane and polyester, and of course quality of the application does matter.

My guess is that the frame in question was not properly coated. A paint thickness gauge would tell if they got enough powder on there. You might check around a local automotive paint supply houses and see if anyone can take a few measurements for you.


Ed
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Old 09-14-05, 11:45 AM   #7
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Thanks for the response!
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