electric heating element rust prevention

Interestingly, I made a couple heatsticks last weekend using the exact same Camco elements and rust appeared during an overnight soak test between the element and nut. I'm now convinced it's my aluminum kettle that's stopping the rust.

 

no rust, POR-15 seems to work well... no anode.

 

did you buy the POR-15 online?

 

no I got it from a local retailer, I called the POR-15 web site and talked to them about the aplication and if it would be ok, then they directed me to a local retailer so I didnt have to wait a week to get it.

 

I spoke with an engineer at Camco and found out that their ULWD devices are made with several types of metal. The bushing is made of steel and covered in zinc. The sheath is made of stainless steel. In my case, I'm using a plastic vessel, so these are the only two exposed metals. The stainless will induce galvanic corrosion of the thin zinc layer and rust will quickly occur. Camco's LWD devices have a nickel covering over everything. Theoretically this should help prevent such quick galvanic corrosion.

 

Nice work! It's about time someone has come up with some answers around here!

I have just resided to filling up my HLT as needed and not the night before to reduce the rust. In the future when I switch from 120v to 240v I'll be sure to get the LWD elements.

Thanks

Mario

 

Also, while oxidation of iron is generally caused by oxygen, and not water, this galvanic corrosion can only occur when the two metals are connected by an electrolyte (water, wort, etc). My mistake was to leave water in my HLT for 3 days while testing my new insulation. The problem can probably avoided somewhat by washing and drying everything as soon after the brewing process as possible.

 

I had the first rust issues with extended time in the water as well, though over time it developed from normal brewing. I will look into the LWD elements for future builds. Looks like Nickel (and nickel alloys) are much much closer to passivated 304 stainless than Zinc (which is wayyyy down the chart)