Rust issue on element/nut

Brewed for the first time with my 120v 2000w electric HLT last weekend. However, there was rust completely covering the threads of the element and locknut, and it dripped onto the kettle and made a little rust puddle about 3" wide.

I thought surely it was the element (stainless) threads but the rust wiped right off. Had to really scrub the locknut though. Also, the element developed a lot of calcium precipitate on it.

I get out the Barkeeps Friend and really worked the threads and locknut, let it sit 30 minutes, then rinsed it well. Hoping the steel passivates.

Anyone else experience this with Rheem element or locknut from Bargain Fittings?

It's most likely the element face/threads rusting which are mild steel I think. I installed a magnesium RV water heater anode. I think it helps some, but not entirely. The HLT is the worst by far for me. I think the acidity of the wort helps the element in the boil kettle. I've also seen some recommend silicone to cover the element face. Another suggestion that someone had was rubbing a little cooking oil on it after cleaning it. And yet another possibility is using an element that has a brass face on it. I may end up doing this, as apparently they're easy to get (don't know where though yet). Nobody has come up with a good option for an element with a stainless face that I've seen.

BTW, I see people say 'just wipe it down after', but that doesn't work for me. I think water gets between the locknut and pot. There's a gap there on my keggle. I try to get a paper towel in there but I don't think I ever get it all.

Thanks for the advice. I was able to find some other threads talking about rust. I think I will try silicone on the inside. I have some I used to seal up the element. Food grade stuff from McMaster.

It's odd, some people have issues and others don't. even with the same element. it must be the water chemistry. I don't have a problem in either the hlt or the bk with rust on the elements.

Our water is hard. Makes excellent beer though.

I used barkeeps on the nut and threads of element and have left both for two weeks. Hoping issue is over.

I have hard water too but don't have rust. I have to do an acid rinse every few brews to remove the mineral deposits on the bk element. The hlt element doesn't seem to accumulate much deposits.

What acid do you use?