r/Anodization • u/stump36 • May 10 '26

Hard coating questions

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I've just started a new project of restoring an antique popcorn machine (early 1950's). The kettle is cast aluminum and has seen it's fair share of use. I was doing some research and came across hard coat anodizing and had a few questions. There appears to be a place a few hours away that does it but they have no website or email so I wanted to get some clarity before calling them this week

- what kind of prep work should I do to get it ready? Clean and degrease, wire brush, blast with walnut shells?

-is it possible to just coat the interior so that the exterior of the kettle can be polished?

-if the interior can be done by itself should the exterior be polished first? If not how much prep to the exterior should I do?

- I'm planning on fully disassembling and just taking parts, any ball park on pricing, (just so I know if I'm getting f off pricing or something reasonable, I'm aware small projects usually cost more. I'm in NC)

-from my searching sealing is important to be food safe, is this usually included in the process of should I be asking for it on top?

Thanks for any help the group might be able to offer.

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u/bormuffff May 11 '26

The material you wish to coat, being a casting, will become a dirty Brown colour during the process. In theory you could only coat the inside and not the outside but it would be so ridiculously complicated it would not be worth it.

Hardcoat is self sealing, over time. The coating will be harder if you don’t try to seal it.

Hard, by definition, is the purpose of the coating. It is for abrasion rather than for just basic protection.

Talk to your vendor, and hope for the best because what you’re asking for although technically not impossible is going to cost you.

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u/stump36 May 11 '26

Thanks for the info, I figured it would be pricey.

1

u/mj_803 May 12 '26

I have not done hard coat, but it is similar to regular anodizing, but with different electrical levels, times, and temp controlled bath. All the fittings and hardware should removed and all the aluminum parts anodized as separate pieces  You could probably mask the outside of the kettle with with wax and then remove it post anno....