Painting Aluminum for submersion

[holy carp]

I've gotten hold of a used Nova Tec Iceprobe chiller, but the paint/coating on the probe itself is flaking and the exposed probe is oxidized.  It appears to be a simple aluminum rod, so I assume it could just be repainted.

 

I know this isn't uncommon for these units, so I'm curious what others have done to coat the aluminum without insulating it too much.  Since it's already oxidizing, do you need to use special primers and paints?  And how do we know which are reef safe?  Alternatively, would it be OK to simply use the naked aluminum probe unpainted?  Will it just augment my phosguard? 

 

[duderubble]

My only experience with aluminum in a reef tank was a lowes clamp light reflector I used over a fuge for a few years. It eventually looked like swiss cheese from salt creep eating through it. I'm surprised a manufacturer would use aluminum to submerse in a salt tank. My instinct is to cover it in one of those plastic temp probe covers they used to use in the doctors office for the electronic thermometer they stuck in your mouth. 

[SaltyBuddha]

Oh man. I just got an ice prove but I didn't hear about this issue. How long old is yours?

 

I wouldn't use plastic or rubber, that would insulate the probe and decrease its efficiency. 

 

Looks like there are a few open forum posts and threads on this, so no definite answer. I'd suggest using Krylon Fusion. Everyone suggests it for aquariums even if Krylon won't. Either the clear gloss or a lightly colored spray. First, remove the rest of the stock coating from the aluminum. You will want a very thin layer to just seal the aluminum while keeping as much thermal efficiency as possible. I'd do a thin coat followed by a light sanding and repeat 2 or 3 times for an even thin coat. You will lose some efficiency, but hopefully not a lot. 

 

Also, some salt mixes contain aluminum (instant ocean) and phosphate removers can leak it as well. Its not natural in the reef tank, but it can be present. I still don't think you would want to use an unknown aluminum alloy in the tank though. If my coating fails, I'd try the Krylon paint.

[MrJoel]

You should be able to find a good thermally conductive resin you could use to coat the probe. If you contact a resin specialty company they should be able to provide one that is a good match.

[holy carp]

OK, so I think the thin coat of Krylon would seal it for while (at least for the season). 

 

But I haven't heard of thermally conductive resin.  Is that like an epoxy?  I'll look into it if I can find a resin specialty company.  Thanks for the tip.