Rust on heating element

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390gopac
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Rust on heating element

Post by 390gopac »

So I'm working on getting my boiler built using a 20L stainless steel bucket and a stainless steel heating element. I was just testing the heating element today with water to make sure I had it wired up correctly and discovered that after an hour or so, rust had started to form at the intersection of the flange and the actual heating element. I guess there's a bit of iron in there somewhere that gets exposed to water?

This seems...bad, right? I can't use this, can I? Is there anything I can do to fix this, like a way to seal that joint on the heating element using materials that are still-safe? I drilled the holes for that specific heating element so if I go with another one I'll have to throw out the bucket (not cheap where I live) and start over. Obviously I don't want to risk my health to save $100, but if there's a way to salvage this element, that'd be preferable.

Thanks for any advice!


Boiler setup
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showing element beginning to heat
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oh no! rust at the base!
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NZChris
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Re: Rust on heating element

Post by NZChris »

Looking at that bucket, that might be the least of your problems. How are you going to seal the lid?
390gopac
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Re: Rust on heating element

Post by 390gopac »

NZChris wrote:Looking at that bucket, that might be the least of your problems. How are you going to seal the lid?
I've got a stainless steel bowl that is the perfect diameter. The two flanges line up nicely. I'll use flour paste and binder clips to seal the seam.

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NZChris
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Re: Rust on heating element

Post by NZChris »

Have you got a link to the specs. for the element?
390gopac
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Re: Rust on heating element

Post by 390gopac »

NZChris wrote:Have you got a link to the specs. for the element?
Sure thing: https://www.aliexpress.com/item/Free-Sh ... 0.0.HtEyjK" onclick="window.open(this.href);return false;" rel="nofollow

Voltage: 220V
Power: 2500W
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NZChris
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Re: Rust on heating element

Post by NZChris »

Does any of it attract a magnet?
390gopac
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Re: Rust on heating element

Post by 390gopac »

NZChris wrote:Does any of it attract a magnet?
Good thought, I never thought to test that. I just assumed it was all stainless.

The heating element itself seems to have a very slight attraction to a magnet, but I think that's due to the core of the element. The flanges though at the end that sit against the inside of the pot have a strong attraction, so I guess those are probably low carbon steel with a coating. They are only rusting in a few places, which makes me think that's where a coating has scraped off...
390gopac
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Re: Rust on heating element

Post by 390gopac »

Any chance I can just wrap the shit out of the flange end with teflon tape? :shock:
rad14701
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Re: Rust on heating element

Post by rad14701 »

390gopac wrote:Any chance I can just wrap the shit out of the flange end with teflon tape? :shock:
That won't resolve the root problem... It is entirely possible that the element you are using was never intended to be used to heat water based products... Some elements are intended for heating oil baths, etc, rather than water... Or perhaps it doesn't have a food grade rating... That's a fairly rapid rust rate..
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still_stirrin
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Re: Rust on heating element

Post by still_stirrin »

390gopac wrote:The heating element itself seems to have a very slight attraction to a magnet, but I think that's due to the core of the element. The flanges though at the end that sit against the inside of the pot have a strong attraction, so I guess those are probably low carbon steel with a coating. They are only rusting in a few places, which makes me think that's where a coating has scraped off...
The "gold colored" material looks like it is cad plated steel, not stainless. That would explain the magnetic attraction. And, it would explain the corrosion due to contact with dissimilar metals.

And, to add insult to injury, once corrosion starts, you won't be able to stop it....strike three! You need to get a better solution.

Perhaps, with that little bucket as a boiler, you can get an external heat element to work. That is, get a hotplate and modify the thermostatic controls with a power regulator. A little 1-1/2 to 2 gallon bucket would be well matched with a 1.5kW hotplate, especially if you add insulation to the side of the bucket.

And for the bowl to bucket seal, put 2 or 3 wraps of PTFE tape around the lip of either the bowl or the bucket and clamp the joint tightly with your binder clips. I would use as many of the smallest clips you can find, placing them all around the opening to be sealed.
ss

p.s. - and next time...smile when you're facing the camera (or the shiny surface of a boiler dome).
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390gopac
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Re: Rust on heating element

Post by 390gopac »

still_stirrin wrote:
390gopac wrote:The heating element itself seems to have a very slight attraction to a magnet, but I think that's due to the core of the element. The flanges though at the end that sit against the inside of the pot have a strong attraction, so I guess those are probably low carbon steel with a coating. They are only rusting in a few places, which makes me think that's where a coating has scraped off...
The "gold colored" material looks like it is cad plated steel, not stainless. That would explain the magnetic attraction. And, it would explain the corrosion due to contact with dissimilar metals.

And, to add insult to injury, once corrosion starts, you won't be able to stop it....strike three! You need to get a better solution.

Perhaps, with that little bucket as a boiler, you can get an external heat element to work. That is, get a hotplate and modify the thermostatic controls with a power regulator. A little 1-1/2 to 2 gallon bucket would be well matched with a 1.5kW hotplate, especially if you add insulation to the side of the bucket.

And for the bowl to bucket seal, put 2 or 3 wraps of PTFE tape around the lip of either the bowl or the bucket and clamp the joint tightly with your binder clips. I would use as many of the smallest clips you can find, placing them all around the opening to be sealed.
ss

p.s. - and next time...smile when you're facing the camera (or the shiny surface of a boiler dome).
Thanks for the tips!

On my heating element the 'gold' parts from the product picture are actually the same color as the stainless. But like rad said, it could be that this heating element isn't food grade anyways. Dang.

I thought about the hot plate, but the bottom of the bucket isn't flat. It's got about a 1 or 2 inch flat spot all the way around that contacts the ground and then the center is raised slightly, so I don't think it will work well on a hot plate unfortunately. It's also more than 2 gallons... it's about 5 gallons. Is that too much for a hotplate?

Looks like I'm just going to have to get a new bucket and start over with a different heating element. This whole thing has been complicated by the lack of good materials here in Israel (or extremely high price of them, like SS pots for over $125...). I think I'll try to get a heating element that looks more like the ones I see on this site the next time I'm in the States. It looks like they have a big threaded flange about 1 or 1.5 inches in diameter. Is that hole thing sealed? So I just gotta cut the hole in the bucket to that 1 or 1.5" size and crank down that big nut with a nice teflon/cardboard washer in there?
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still_stirrin
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Re: Rust on heating element

Post by still_stirrin »

390gopac wrote:I thought about the hot plate, but the bottom of the bucket isn't flat. It's got about a 1 or 2 inch flat spot all the way around that contacts the ground and then the center is raised slightly, so I don't think it will work well on a hot plate unfortunately.
If that "ring of contact" would be in contact with a coiled burner element (on a hotplate), I think it would conduct the heat into the boiler just fine. And typically on a coiled burner element, the center of the element doesn't have any of the burner coil anyway. It really depends on how stable the bucket and still would be when setting on the hotplate. You might need some additional balancing support for it.
390gopac wrote:It's also more than 2 gallons... it's about 5 gallons. Is that too much for a hotplate?
No, not too big, but on the upper limit for sure. I have a 16-quart stainless stock pot boiler that I heat on a modified hotplate (with an 8" diameter heating element). It works fine for washes up to about 3 gallons. It works especially well for small batch low wines, like making a gin, etc.
390gopac wrote:Looks like I'm just going to have to get a new bucket and start over with a different heating element. This whole thing has been complicated by the lack of good materials here in Israel (or extremely high price of them, like SS pots for over $125...). I think I'll try to get a heating element that looks more like the ones I see on this site the next time I'm in the States. It looks like they have a big threaded flange about 1 or 1.5 inches in diameter. Is that hole thing sealed? So I just gotta cut the hole in the bucket to that 1 or 1.5" size and crank down that big nut with a nice teflon/cardboard washer in there?
I understand the difficulty sourcing proper (economical) still building equipment where you live. You may be able to use the internet to source and ship hardware to you (is that possible?). And I know, from my New Year's journey to Jerusalem last year that there are many, many fine restaurants there. I know that they get cooking supplies from somewhere. So you may simply have to be resourceful to find them....garage sales, the open markets, etc.?

But, to back up...I believe a bucket would work as you'd originally planned. Simply, don't use that particular heating element. Here in the USA, water heater elements are available at local hardware stores for replacement in our "whole house" water heating systems. They're reasonably priced and actually quite available. They are fitted with a 1" MNPS (male national pipe straight thread) for which you can source a tri-clover adapter to mate with a stainless ferrule to be welded, or silver-soldered onto the side of the vessel. The element is then threaded into the adapter which is clamped to the ferrule which you've attached to the boiler. The heating element can be removed for replacement if/when needed that way. It is an elegant solution to the problem.

Wish you luck as you begin the "needle in a haystack" search for materials. I think you've got a good start however, and in the end, you'll be successful.
ss
My LM/VM & Potstill: My build thread
My Cadco hotplate modification thread: Hotplate Build
My stock pot gin still: stock pot potstill
My 5-grain Bourbon recipe: Special K
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