Home-made furnace for hardening

Hi gents!
I decided to make a muffle furnace
I read the forums, made calculations, collected materials.
For hardening of knives and razor blades to me more than enough
Internal Dimensions: Diameter - 50 mm, length - 280 mm. The design temperature up to 1000 degrees. Celsius.
Automatic first made on thyristors, but for some reason he was burned in the tests, and I remade by a magnetic switch. It seems as long as everything works. Will soon begin full operation, except the furnace should be much more.
Attachment 130456

Cool. What materials did you use?

The base of the big old electrical fuse
Heater - nichrome wire 1 mm.
Plastering - chamotte clay to 1600 C
Winding - asbestos cloth.
Thermal insulation - basalt wool
The rest can be seen in the photo

Can you still get Asbestos cloth in Russia?

Do not quite understand your question.
Asbestos we can buy

That looks fantastic mate :tu....Thanks for sharing with us !!

How nice, ... more info as you go please :-D

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Originally Posted by GVIkzn

Do not quite understand your question.
Asbestos we can buy

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Asbestos is highly carcinogenic (asbestos particles cause lung cancer), and is not sold anymore in many Western European countries.

That is the coolest thing I have seen in a while. Thank you for posting the pictures. It looks like a great design and build.

Charlie

Quote:

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Originally Posted by Bruno

Asbestos is highly carcinogenic (asbestos particles cause lung cancer), and is not sold anymore in many Western European countries.

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I know
Therefore, with the open side of all asbestos I smeared with chamotte clay.
If there are cracks, they also glossed over.
You have a very large selection of thermal insulation, you can do without asbestos. I used what I had.

Quote:

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Originally Posted by DDTech

How nice, ... more info as you go please :-D

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What exactly is necessary, in my mind, everything is clear.
If you have any specific questions - ask.

How does the temperature control work?

Heats up very quickly, such as a power of about 3.5 kW and a small volume of the chamber. The inertia of the upper side of 20-30 degrees C, the lower 2-3. It is only necessary to get used to it.
To reduce the heating capacity built into line powerful diode that allows two times lower AC power.
I hope that the correct answer to your question.

Quote:

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Originally Posted by GVIkzn

What exactly is necessary, in my mind, everything is clear.
If you have any specific questions - ask.

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Nothing specific. I just meant, i'd like to see/hear more of it like being in action.

This is crazy.... Asbestos has a direct link to Bronchocarcinoma and Mesothelioma. I hope you are wearing a mask when you work with it

Thank you! For something that you think about my health. Always will wear a mask.
About the carcinogenic properties of asbestos I know. Asbestos-exposed areas I smeared fireclay clay. If cracks will continue to gloss over.
So far, I can not spend valuable work with the furnace, we must also beefed up. Time is also not enough
We sell loose asbestos in the store and it is often used for thermal insulation.
We have many sayings on the subject of health. For example: "What does not kill you makes you stronger." But it's all a joke. Once again, thanks for the warning!

Most of the threat from asbestos is air born particles. In California I could not tell you how much water pipe is in the ground that is made with asbestos in it. More feet than dollars in the national debt I would guess. It's breathing it that will kill you.

Yeah it's funny, you mention asbestos in the US and it's like there was a radioactive leak. In other countries you probably get a "huh?" from people.
Like anything else just take caution around it
That's a quite a setup there - some nice engineering.

es. But the asbestos blanket shown in the pics of the OP is exactly what is dangerous about asbestos: airborne asbestos particles galore.

most of australian housing from about 1930 -1980 seems to have been constructed in part from asbestos. its a nightmare from a renovation point of view.

Now they use crystalline silica instead. Does all the same damage to lungs except it is not cancerous. Breathing anything besides air is not a good idea.
And that is a darn nice little heater ! Somebody needs to draw up some plans and a how too. If I knew anything I would :<0)

Asbestos presents one of the great contradictions between Canadian domestic and foreign policy. It is effectively banned for all domestic use because it is so incredibly dangerous. And no, that isn't just alarmist. The rates of disease and death amongst former asbestos workers is shocking. But the truly scary thing is the very high rates amongst those workers' families. The workers would come home with the fibres on their clothes, etc., and then their families would in turn be exposed. Many people who never set foot in an asbestos mine or processing facility have died, are dying, and will die from mesothelioma from very minimal exposure.

Because of this, a decision was made in Canada that the material was simply too dangerous for consumer use, and so it was banned. But we apparently have no problem exporting tons and tons of the stuff to other countries. This was done largely to protect the economies of a number of single-industry towns where it is mined. Not something I'm particularly proud of.

And we have the same issue with older houses here too. There are legal requirements when selling a home to disclose whether the house contains asbestos insulation, and there is an entire industry that has developed to remove the stuff. When left undisturbed it is relatively harmless. But if anything is done to disturb it and release fibres to the air, look out. So if you discover your attic is filled with asbestos insulation, whatever you do, DO NOT try to deal with it yourself or otherwise disturb it!

So yes, please be careful with it! And thanks to GVIKzn for showing us the furnace.

Asbestos may be very bad for your health, but it is an excellent insulator as GVIKzn has shown. Looks like he scrapped together a very workable electric oven, I only WISH I had the skills to put together something that nice. Thank you for sharing kind sir!

When I was a Boiler Tech. in the Navy we used asbestos as insulation & also had asbestos gloves we used to pull burners out of the boiler. After we went in the yards & they removed all the asbestos & replaced all our asbestos gloves with some "OTHER" kind they didn't work for crap. People were getting burns with these new gloves & also dropping the burners because of the heat.
My job while we were in the yards was to get things we needed with coffee as a trade item. you would be surprised what 5 Lbs of coffee can get you in the yards! Anyway I told a friend in the yards I sure would like to get a couple of pair of asbestos gloves. Five pounds of coffee & I found two pair of asbestos gloves in a drawer of my work bench. We used masks from then on when we were using the gloves so the chance of getting it in our lungs was very small.
Most of the people having problems were car mechanics that did brake work. There are many different types of asbestos & I have read that the asbestos in brake shoes & pads were the worst kind being very sharp fibers.
Don't get me wrong, it is very dangerous stuff but used safely it is still one of the best tools for the job at hand.

Slawman