electric heating element rust prevention

Hi all, so I've been doing some reading about using eletric heating elements in SS kegs and ran into people talking about the mild steel face plate of the heating element rusting due to galvanic cathode reactions (like those in hot water heaters, go figure, lol).

I saw that some people put JB weld on the surface, one suggested POR-15 (http://www.por15.com/POR-15/productinfo/1GB/), and some have suggested a sacraficial anode such as an aluminum block or magnesium fire starter.

So I have a few questions about this. First off, if you put JB weld or POR-15 on just the face plate, wont you still get rust on the threads the water has access to inside the nut that holds the element on? Then if you do put it on the threads, you'll have to do it at the time of insersion in which it now becomes a fairly permanent installation (maybe get it out with a breaker bar? haha). I dont like the idea of it being permanent. But what if I plastered the thing in teflon tape to protect the threads?

I dont like the idea of sacraficial anodes because I'm worried about the added magnesium or aluminum ions floating around in the water/wort that might effect the taste of the beer (I suppose the aluminum anode would effect taste less), or are the concentrations of the ions so low that it doesnt matter?

The other crazy idea I had, though kind of expensive, is a powered anode such as: http://www.sdsmarket.com/9006247005_Powered_Anode_Rod_Short_p/powered_anode-short.htm

A little expensive I know, BUT then you have no metal ions running around and no galvanic reactions.

I'm trying to find the best solution for the price. I could build my own powered anode from scratch if I could get a schematic for one, but I cant seem to find one (much cheaper than buying one I bet).

I wouldnt mind using the POR-15 solution (it seems to be a nice one) but I dont want a permanent instalation, and just doing the face plate I'm worried about rusting the threads.

Oh, and here's the elements I'll be using: (the normal camco ones) http://www.ronshomeandhardware.com/5500W-240V-Ripp-Element-p/808790.htm


Are there any better idea's/solutions per cost? or are my pressent concerns not valid?

thanks!

I suggest using the aluminum anode. Fears about aluminum are unfounded; for some reading check out this link: https://www.homebrewtalk.com/f11/faq-aluminum-pots-boil-kettles-49449/

People using aluminum boil kettles have no rust issues with their elements because of the nature of the mild steel/aluminum. I personally use an ~2.5" x2.5" piece of aluminum flashing ($0.25 at the local hardware store) drilled to slide over the threads of my elements. Works perfectly-- zero rust.

i understand about the aluminium kettles, but being that it's used as a sacrificial anode, doesn't that pretty much guarantee that it's ending up in the beer? does your aluminium corrode or need to be replaced?

With an aluminum pot, given that you have a mild steel as the face plate of the element, the aluminum pot will act as the anode and will "pit" as the ions are replaced, but with a pot like that my guess would be that it would take 100 years for you to really wear your pot down (or longer), and given its very large surface area, the pits are likely so small that every time you scrub the pot they go away, so you'll never notice, and the pot will more likely ware out for other reasons before it does for being the anode. Typically in a hot water heater, 40 gallons, constantly heating 40 gallons of water a day, a typically 42 inch long 1 inch thick anode rod will last 6 years.

Given that it would take a long time to effect your pot, and the flashing suggested above will eventually ware out, by pitting, then breaking apart, and when it does, you simply replace it.


Aluminum flashing eh... that sounds like the right price and it has a larger surface area for good conduction to act as the anode.... After reading the FAQ it seems that there isnt enough aluminum ions infused into the wort over a 1 hour boil to cause any issues...

Given the cheapness of the flashing, and its ease of install, I think I'll just go with that, and then replace it after its been eaten away (after how many years of use? haha).

Wayne at bargain fittings sells aluminum 1 inch NPS hex nuts for the heater elements too, and they are only a few dollars more than the SS ones, but the flashing is so cheap and easy I think I'll just go with that.

kezgin,

As shushikiary states, there will only be trace amounts of aluminum (less than what is found in a "Daily" vitamin)... I have had my flashing anode in use for ~6 months now without any physical change to the naked eye, and it spent almost two weeks completely submerged too. Under microscopic conditions I am sure there is something happening, but again, that is going to be statistically insignificant amounts for a 5 gallon batch boiling for 60-90 minutes.

But, def do what you feel comfortable with, but I also warn against being afraid of the bogeyman!

I have been dealing with this same problem since I made my electric keggle HLT. I recently tried using and aluminum bolt to act as the anode, but I still have been getting rust. Does the sacrificial anode have to contact the element base? or since the rusting had already started ( I cleaned it really well between tests ) it's too late to stop? Or I just have a really crappy water heated element?

I was really excited about this project, but now not so much if I'm going to get rust every time I use my HLT.

I think you guys are over-analyzing this.

Food grade silicone on the element face and threads (once installed) will prevent further rust and still allow removal in the future. Simple, safe, long-lasting, and inexpensive.

The way cathodic protection works by way of sacraficial anode, you need to have a GOOD connection between the anode and the electrical path to the cathode. Meaning that you need a fairly good connection between your metal brew pot and the sacrificial anode, as well as it being IN the water.

The easiest way to make sure this works right is to have direct contact to the cathode as you just mentioned, but it's not required to work.

The other way is to use a metal that is MUCH more "sacrificial" like magnesium instead of aluminum. This is why the mag fire starters can just be dropped in, because they dont need as good of a connection to work as well (higher potential, therefore higher resistance is ok).

Here we can see the table of the potentials of each metal: http://en.wikipedia.org/wiki/Cathodic_protection

Notice the magnesium is over 2x the negative potential of the aluminum, it's a better sacrificial anode.

Of course there could be other problems with your setup that we dont know about. It is entirely possible that you left some rust behind in the pits of the face plate and that is what is coming back.

Perhaps it would be a good idea to remove your whole element, and soak it in a rust removing solution to make 100% sure you got all the rust off.


Lamar guy: I think that might also work as a solution and not make it permanent, but does it seal well enough, and how did you seal it, did you just plaster the whole element nut and parts in the water (maybe a picture of exactly what you did would be helpful)?

That's is an excellent answer and feel better about getting this to work without a band aid fix. Just to show what I have here is a picture. I have the element installed with a stainless nut and o-ring and a aluminum bolt that I screwed into the pot. I thought this was enough contact but maybe it's not. Also I believe I have some residual rust left behind.



Thanks for the help!

Mario

cyberbackpacker said:

kezgin,

As shushikiary states, there will only be trace amounts of aluminum (less than what is found in a "Daily" vitamin)... I have had my flashing anode in use for ~6 months now without any physical change to the naked eye, and it spent almost two weeks completely submerged too. Under microscopic conditions I am sure there is something happening, but again, that is going to be statistically insignificant amounts for a 5 gallon batch boiling for 60-90 minutes.

But, def do what you feel comfortable with, but I also warn against being afraid of the bogeyman!

Click to expand...

gotcha. i wasn't sure if there would be any negative impact on water chemistry or not, but if it's hardly decaying i can't imagine it's that bad

mariojr said:

That's is an excellent answer and feel better about getting this to work without a band aid fix. Just to show what I have here is a picture. I have the element installed with a stainless nut and o-ring and a aluminum bolt that I screwed into the pot. I thought this was enough contact but maybe it's not. Also I believe I have some residual rust left behind.

Thanks for the help!

Mario

Click to expand...

I just had a thought... looking at the picture you most likely have a fine connection of the anode to the keggle (the head of the bolt most likely is compressed against the out side of the keggle), but if you put the rubber o-ring on the back side of the element, and centered it just right upon insertion and tightening it's entirely possible the cathode (the element) has no electrical contact to the keggle, thus you cannot protect it. I'd suggest putting the anode in direct contact with the element if possible just to MAKE SURE it can protect it. (along with removing all the original rust).

You could also remove all the original rust and try a silicon sealant as suggested. I read a post were someone tried this though and they got rust back (they worried they didnt fully remove the original rust as well), and said that the sealant wore off after a few brew sessions (perhaps it was the wrong silicone sealant or didnt get a good bond to the element? idk).

looking at your picture, I'm starting to wonder if painting the entire end of the cap and the threads exposed (which arnt that many) in POR-15 would work well (similar to the silicone sealant, but POR-15 is serious stuff, I also gave the manufacturer a call and they said it's food safe after its dried and that it would easily with stand boiling temps)(the silicon o-ring should prevent water to the threads after the SS nut), and it would still be possible to remove the element, it would just take some elbow grease.

Honestly, I believe the sacrificial anode concept is dead in the water. No pun intended.

Wort is acidic, and as such, provides more than enough electrolytes to expedite corrosion. As a practical example, I've seen converted aluminum pots with a rusted heating element face. You're not going to get a larger aluminum anode than the pot itself.

shushikiary said:

Lamar guy: I think that might also work as a solution and not make it permanent, but does it seal well enough, and how did you seal it, did you just plaster the whole element nut and parts in the water (maybe a picture of exactly what you did would be helpful)?

Click to expand...

Sorry, I don't have any pictures handy. If I remember later, I'll snap one.

A thin layer of silicone is all that is necessary to encapsulate the heating element face and threads. Avoiding scrubbing it during cleaning (I recirculate 150F PBW, so no scrubbing) and the silicone should last for many years.

lamarguy said:

Honestly, I believe the sacrificial anode concept is dead in the water. No pun intended.

Wort is acidic, and as such, provides more than enough electrolytes to expedite corrosion. As a practical example, I've seen converted aluminum pots with a rusted heating element face. You're not going to get a larger aluminum anode than the pot itself.



Sorry, I don't have any pictures handy. If I remember later, I'll snap one.

A thin layer of silicone is all that is necessary to encapsulate the heating element face and threads. Avoiding scrubbing it during cleaning (I recirculate 150F PBW, so no scrubbing) and the silicone should last for many years.

Click to expand...

Hmm, good to know. Well I could always do... BOTH! hahahaha... overkill but for 50 cents worth of flashing who cares. Though, in the aluminum FAQ they said that acidic doesnt bother aluminum unless it's very acidic, and wort is only slightly, though they did say that basic would be very bad, so perhaps someone didnt watch their PH while fly sparging and got a high PH? It could also be that they didnt have a good electrical connection to the aluminum pot from the element. I'll look forward to the pic so I can see exactly what you did (thanks!).

I removed my previous response because I felt it was irrelevant, but thanks for all the help. I'll post back after I try a few of these options.

Thanks again.

Mario

I installed two aluminum lock nuts from bargain fittings on my two elements and have not had any rust so far. I didn't use teflon tape and they contact the elements directly. I'm not sure how long they will last but they work for me.

Here is what I have come up with after a preliminary test on the old element. It had a little rust, but I'm going to attribute that to not being entirely clean. So I moved forward with the full on test.

I bought an new element and some sheet aluminum. I made my anode out of the aluminum by cutting a square and making a hole with my step-bit to fit the base of the element.



Then I cut a new washer for the outside out of some silicone tubing I had, and installed it in my keggle.




Filled it with some water to sit overnight to conduct my test. I know this isn't new groundbreaking stuff but it makes me happy. I hope.


Mario

looks good, let us know how it goes!

HarkinBanks said:

I installed two aluminum lock nuts from bargain fittings on my two elements and have not had any rust so far. I didn't use teflon tape and they contact the elements directly. I'm not sure how long they will last but they work for me.

Click to expand...

When did he start selling aluminum? I dont see it on the site.

willynilly said:

When did he start selling aluminum? I dont see it on the site.

Click to expand...

I didnt see them either, so I emailed him and he said he can order them, but are a few dollars more than the SS ones, you just have to email him to get them from him, his name is Wayne.

HarkinBanks said:

I installed two aluminum lock nuts from bargain fittings on my two elements and have not had any rust so far. I didn't use teflon tape and they contact the elements directly. I'm not sure how long they will last but they work for me.

Click to expand...

How long and how many brews has this been the case?

I prefer half couplings, I found some at McMaster for $2 each that are aluminum... I may experiment with them!

Yeah I had brought this up elsewhere, I tried the silicone sealant and it just came off and rust started behind it after a few brews, I've used it elsewhere and it has been fine, ah we.. Yes with the Por-15 I don't really have much in the threads, a very very light coat. I let it dry before screwing on the element. I've had no rust issues after putting that on, but I like the Aluminum flashing idea better (or both...) If I were to get a pinprick hole in the Por-15 protection it would accelerate the corrosion on that spot due to such a small area being exposed.

My plan for my new build was a Aluminum nut, worried that stuff would get stuck behind the flashing, has anyone had difficulty with cleaning around the flashing?

FAIL



I'm getting discouraged with this since science isn't working, and I'm thinking maybe I'm doing something wrong. Although it did seem a bit better than without the aluminum square. It seems most of the rust is forming where the element penetrates the body of the threaded piece. I guess because the plating isn't as solid there? Could the missing link be exchanging the stainless nut for an aluminum one?

Thanks for the ideas.

Mario

mariojr said:

FAIL

Click to expand...

I hate to say I told you so....But, try the same experiment with wort, which has a lower pH and a higher temperature to help accelerate the corrosion process.

IMHO, the only two viable solutions are (1) light silicone layer (continues to work well for me) or (2) food safe high temperature epoxy paint.

I am merely embracing the iron oxides on my element bases...

stevehaun said:

I am merely embracing the iron oxides on my element bases...

Click to expand...

Not a bad thought My galvanized pipes are FULL of rust anyway. My wife throws away anything in the kitchen that gets a spot of rust on it, wonder if I should show her the inside of our plumbing?

Those pics are so frigging bizarre. The element in my kettle is 15 months old, and I've lost count of how many batches run through it. Not even a hint of rust...

jkarp said:

Those pics are so frigging bizarre. The element in my kettle is 15 months old, and I've lost count of how many batches run through it. Not even a hint of rust...

Click to expand...

What type of element do you have? I bought this one at Home Depot and it's a Camco. Maybe this is the deciding factor.

I'm also only using it in my HLT and no wort is going to touch this since my kettle is gas fired.

Mario

jkarp said:

The element in my kettle is 15 months old, and I've lost count of how many batches run through it. Not even a hint of rust...

Click to expand...

Is the element face mild steel or chrome plated? Night and day difference.

Mine is Camco as well. Kettle is aluminium.

Seriously, don't you guys have something more important to worry about? Replace the element once a year if it really bothers you. You'll spend more time and money on prevention than you would on replacement.

mariojr said:

FAIL

I'm getting discouraged with this since science isn't working, and I'm thinking maybe I'm doing something wrong. Although it did seem a bit better than without the aluminum square. It seems most of the rust is forming where the element penetrates the body of the threaded piece. I guess because the plating isn't as solid there? Could the missing link be exchanging the stainless nut for an aluminum one?

Thanks for the ideas.

Mario

Click to expand...

was this a new element or one that you cleaned the rust off of? if there was any rust left maybe it still will spread

stevehaun said:

Seriously, don't you guys have something more important to worry about? Replace the element once a year if it really bothers you. You'll spend more time and money on prevention than you would on replacement.

Click to expand...

You've wandered into the wrong topic, steve. This is DIY, which is latin for obsessive-compulsive overachievers engaged in spending inordinate amounts of time and cash on making something they could buy down the street.

kezgin said:

was this a new element or one that you cleaned the rust off of? if there was any rust left maybe it still will spread

Click to expand...

This was a new element and was in water for about 14 hours.

hmm... this really has my mind jogging... You didnt use any teflon tape on the nut right (shouldnt make a difference, but good to know)? Are we also sure that it's rust and not some other residue left behind from your water?

oh... is that the same SS nut? did the nut perhaps have rust on it from the previous element?

It's also possible the aluminum flashing has a strong oxide layer built up on its surface and that perhaps sanding it moderately before installation would help.

You may simply need to get a better anode material (magnesium fire starter) and/or coat it like lamar says. I feel bad with you spending money on extra heating elements. This must have something to do with your water sense other people use the same element with the aluminum nuts and dont have rust (I fear for your water heater). It could be that the surface area of the aluminum isnt large enough to completely save your mild steel, but that's speculation. Seeing as how it's compressed between the nut and the wall of the keg, assuming you have an electrical connection from the nut to the element (which you most likely do, even with teflon tape), everything seems to have been done right. If I was you, I'd either coat it with POR-15, or try a magnesium fire starter.

I'm starting to understand your frustration mario.... This tells me that I'll be doing both just to be ridiculous. Time to go pick up some POR-15.


conpewter, did you just do a single coat of POR-15, and did you do any of their recommended prep steps (I'm assuming you did it on a new element)? I talked to them on the phone and they said that if I put the recomended 3 layers on that the nut would no longer fit over it, so did you just force the nut on? And when the nut went on did it strip the POR-15 from the threads?

I did the cleaning part (bought their little kit) and then probably put two coats on. I think I brushed on a really light layer once on the threads, but I still had to dig some out when I put the nut on (razorblade) The ones before that I just put it on the face and didn't worry about the threads, I've not seen any rust stains or anything from it, so I think I'll just be Out of Sight Out of Mind on the threads...

Would this be a good choice to try?

http://www.walmart.com/ip/Coghlan-s...00000003260410&ci_src=14110944&ci_sku=8586954

mariojr said:

Would this be a good choice to try?

http://www.walmart.com/ip/Coghlan-s...00000003260410&ci_src=14110944&ci_sku=8586954

Click to expand...

Sure, to ignite thermite!

lol, thermite, I LIKE IT!

In posts from other threads I've read I believe that is what they were referring to, yes. The trick is getting the magnesium part to have a good connection to the SS keg or the steel part of the element.

For your case I'm starting to think that coating it with silicone or POR-15 might just be the better solution... from conpewters experience I think POR-15 would be the be all end all solution. But if you want to try the fire starter I'd love to see the results (dont spend the money if you dont want to, I feel bad having you do experiments at your cost).

I just had another thought.... did you ground your keggle to earth ground? If not, then the cathodic protection may not work properly.

Well I got the rest of the parts for my keggle, and went out and got some POR-15. That stuff is serious business. I put 2 coats on and let it try, I didnt have to do anything and the nuts still fit just fine. I coated the face plate and the threads. It seems to be working nicely so far.

I did a test boil and let the water sit in it for 5 hours so far, and no issues. I dont have pics of the elements with the POR-15 on them, might grab some later, but here is a video of the thing boiling: