Color Change in my mini Boiler

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artooks
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Color Change in my mini Boiler

Post by artooks »

Hi Guys,

I need some help with a problem I faced today, cannot decide what to do, I have a small boiler in order to use it as potstill the capacity is 2.5 Gallon it has a 1000w heating belt in the outside but sometimes when I have to distill gin or our traditional drink raki, I have to go to even less volume then I cannot use the heat belt instead I use a 1000 watt hotplate that I have adjusted the sides to come into contact with the bottom of the boiler, I also pot stilled gin and raki up until now with this, that was very happy with the results but today when I distilled as usual I saw a color change in the bottom of the boiler, it happened probably it got overheated or some other cause, my boiler is a 304 SS milk can so I am wondering if this color change in any way a bad thing just asking this as a safety precaution also is there a way to get rid of it, and what should I do to not experience it in the future I really appreciate your help, attaching some pictures also the color change image as well.
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seamusm53
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Re: Color Change in my mini Boiler

Post by seamusm53 »

Blue-ing discoloration of steel is common with overheating (put a stainless knife in a flame) but shouldn't seriously affect structural integrity for a boiler.
artooks
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Re: Color Change in my mini Boiler

Post by artooks »

Ok but how can I avoid it and is there anything that I can revert this back.
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Danespirit
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Re: Color Change in my mini Boiler

Post by Danespirit »

Like he said, it's common for an overheated stainless steel.
Do you run a controller on that plate, or is it just running flat out full power..?
A thick piece of steel plate (5-10 mm), will help to distribute the heat more evenly. :idea:
Use some very fine emery cloth for wet polishing (grid 800 or even 1500), to polish the discoloring away.
The stainless will "regenerate" itself with a protective oxidation layer on top.

What on earth have you done to the corners of that poor hot plate..? :shock: :lol:
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Re: Color Change in my mini Boiler

Post by artooks »

Danespirit, yes I am running a controller on that plate but at the beginning I opened it full throttle maybe this is why it happened.
this is my spirit boiler :) but sometimes I distill like 3-4 lt maybe next time I should open it less in order to not have this problem,
this hot plate was sitting all alone in the roof, now it serves for a better purpose :) I had to cut down the corners evenly so that when
I put the boiler on top it serves 2 functions, it keeps the boiler intact, and also the bottom part barely touches the hotplate,
is that ok if I leave it like this, I am wondering will this go if use the green part of scotch brite, but it looks like it is engraved, just wondered
if this could cause any safety problems, but I guess not, so you are suggesting to use a 5mm thick steel plate in between, will this completely
removed once I apply scotch brite ?
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Re: Color Change in my mini Boiler

Post by StillerBoy »

[quote="artooks"but today when I distilled as usual I saw a color change in the bottom of the boiler, it happened probably it got overheated or some other cause]

The discolour was cause by overheating somehow.. just use a stainless steel cleaner such as Bar Keepers Friend, and it will clean up just fine.. I would check out what cause it to over heat in that spot..

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Re: Color Change in my mini Boiler

Post by Pikey »

I was under the impression that that "blueing" on stainless, chaged the crystaline structure - mking it susceptible to rust, and that it needed specialist treatment ?
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Danespirit
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Re: Color Change in my mini Boiler

Post by Danespirit »

Ahh I see why you did "molest" that poor plate... :wink:
Scotch-Brite as suggested, or a stainless steel cleaner might take it away....I'm not sure though, that's why I recommended the emery cloth (I know it works).
If you want an almost mirror like finish and want to spend time on it, you can polish it afterward.
I wouldn't bother, though....it's only the inside of the boiler and as long as you can clean it without any residue left, you're golden.
so you are suggesting to use a 5mm thick steel plate in between, will this completely
removed once I apply scotch brite ?
The reason why you have that pattern on the bottom is that the hot plate has a cavitation in the middle.
That means the boiler wouldn't touch the plate all the way and as you started heating that thing up, the plate developed excessive heat.
An air pocket in the middle made sure it didn't burn the bottom there. Instead, it got burned right beside the pocket...hence the ring pattern.
That's the reason why I suggested a steel plate...to distribute the heat more evenly.
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Re: Color Change in my mini Boiler

Post by artooks »

Hi Everyone, after trying to find a solution, I find a solution that I wanted to share with you, if you experience something like this, first cut a lemon in half and scrub it in the bottom of the boiler or where the discolouration happened, then put in some white vinegar boil it for 15 minutes and empty the boiler and clean it with a cloth you will see it will be like brand new.
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Re: Color Change in my mini Boiler

Post by der wo »

Yes. Just right now I wanted to ask you what you distilled. Gin? And then I had written, that probably the next wash will cure it, because a wash is acidic. :thumbup:
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Re: Color Change in my mini Boiler

Post by RedwoodHillBilly »

artooks wrote:Hi Everyone, after trying to find a solution, I find a solution that I wanted to share with you, if you experience something like this, first cut a lemon in half and scrub it in the bottom of the boiler or where the discolouration happened, then put in some white vinegar boil it for 15 minutes and empty the boiler and clean it with a cloth you will see it will be like brand new.
Citric and/or acetic acid will somewhat pacify stainless. Probably the best way to do it is to electro polish with phosphoric acid (you can use Star-San in a pinch) as the electrolyte. I've done this before using a homemade system. The technique is left as an exercise for the student. :)
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Re: Color Change in my mini Boiler

Post by OtisT »

Artois. The issue is bad contact between your boiler and hotplate. You can help avoid that problem by cleaning the bottom of your boiler and the top of your hotplate just before use, to ensure there are no high spots and that there is a good surface to surface contact. I also take extra caution to center my boiler, and I also give the boiler a little twist on the hotplate to ensure there is good contact.

A metal heat sync between the hotplate and boiler will reduce the chance of such a burn, but you should still pay attention to surface to surface contact for efficiency sake.

This just happened to me with a small piece of plant material that was stuck to the bottom of my boiler.
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Danespirit
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Re: Color Change in my mini Boiler

Post by Danespirit »

Pikey wrote:I was under the impression that that "blueing" on stainless, chaged the crystaline structure - mking it susceptible to rust, and that it needed specialist treatment ?
The heat tint / temper color depends on various factors...steel composition, heat applied, time, and atmosphere (how much oxygen present).
When we speak crystalline structuring of stainless steel, there are two main forms...ferritic and austenitic.These symmetrical structures are also called allotrope.
An allotropic phase change occurs by excessive heating of the metal, so you are correct Pikey.
I won't bore you with my scientific blah, blah....so just a short explanation.
How much the structure is changed or if, depends vastly on the above-mentioned factors, heat beeing the main factor.
You have probably noticed the bluish color on exhaust systems in stainless..on a bike that has taken some serious riding it's very prominent.
This is caused by the heat of the gasses passing through, but the exhaust won't rust and fall apart in just a few weeks...the temperature simply wasn't high enough.
When one weld or hit the metal with a flame, things change and one has to be careful not to overheat it.
Overheating will cause some of the Chromium (and other materials) to evaporate, which is really bad for the properties of the material (strength, corrosion resistance etc.).
I don't think our friend ruined his boiler, though. The hotplate would have to be red hot for a longer period of time.
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Re: Color Change in my mini Boiler

Post by just sayin »

Did you run your boiler dry? I cannot figure out how you can get stainless hot enough to blue with water/water and ethanol mixture inside.
artooks
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Re: Color Change in my mini Boiler

Post by artooks »

No I did not run my boiler dry, I heated from the bottom part but maybe some part touched and the other part did not I am thinking to keep it a little bit higher like barely touches maybe that could also help
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Re: Color Change in my mini Boiler

Post by UrToopid »

A 14 gauge (or thicker) Copper disc on top of your hot plate would work much better than other metals.. Copper has superior heat transfer and will evenly distribute the heat over the entire surface even if the hot plate doesn't contact the base of the cooler evenly.


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artooks
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Re: Color Change in my mini Boiler

Post by artooks »

Hi,

Today I have cut a 8mm thick aluminum piece in order to transfer the heat evenly the middle part is taken out therefore, from my trials I saw the the boil happens in the sides ehich is good. I will try to distill again.
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OtisT
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Re: Color Change in my mini Boiler

Post by OtisT »

artooks wrote:Hi,

Today I have cut a 8mm thick aluminum piece in order to transfer the heat evenly the middle part is taken out therefore, from my trials I saw the the boil happens in the sides ehich is good. I will try to distill again.
Good luck. I'm sure you already know this, but you will loose efficiency with the heat sync ( won't get as hot), and adjustments to your hotplate will take longer before they take effect. Just something to take into consideration. I remove my heat sync when stripping, otherwise it is too slow on my rig.
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