Home Made Electronic Furnace - Hi Everyone, First Post

[Oliver St John Mildmay]

Hi All,

First Post;

How are you all? Hope you're staying safe and well from the virus and other things? 

Just registered this evening. P r e t t y Thorough Forum. Just The Place. 

Starting to play with recycleable materials (in between running a shop and mental health stuff and learning gardening), Aluminium, plastic, maybe other stuff. Looking to POSSIBLY, lol, make an electric furnace to melt Aluminium, Copper, maybe Brass. For small things, keyrings stuff, trumpet buttons, Christmas presents, .... just as a hobby really, not really to make money.

I can get a long, stretchable, heating coil wire from ebay for the heating element for about £10 delivered. Does anyone know if I just attach a normal mains plug (UK) to it and plug it in and it will work / heat? or do I need to add electronics a resistor maybe (and maybe an on off switch lol).

Remove eBay link per TOS

Great To Meet You All

Olly, Oliver

*Sorry, if it led to money making stuff, nothing wrong with that, G r e a t, but just as a hobby really

[Scott NC]

[Steve Sells]

If you have to ask about such a basic electrical question, then I highly advise you to hire the wring out to an experienced electrician and NOT do it yourself

[Buzzkill]

Building an electric foundry, furnace, or oven that works well is a little more involved than grabbing a coil of nichrome, kanthal, etc. wire and a couple switches.

I strongly recommend you do some research before you dive in head first. 

If you want to maintain a specific temperature, you will want a PID controller.  You'll need insulating material, such as ceramic fiber blanket or insulating fire bricks.  I recommend the bricks for use with heating coils. You'll also need to find some plans from someone who has built something similar that works well (they will have done all the math) or you will need to be able to calculate how much current you will pull to get the heat you need for the size of your furnace.  If you don't get the volume of the furnace, the current draw, and the coils matched well, you will either not achieve the heat you want in a reasonable amount of time (if at all) or your heating coil will fail quickly.

Just for reference sake, I built an electric oven for heat treating and I spent about half what it would have cost me to buy a commercial product of similar size and capability.  It also took me a couple weekends to put it all together and get it working properly.  I did not work off of anyone else's plans, so I had to do all the math and determine all the materials needed myself.  I recommend using good plans after that experience.

[ThomasPowers]

If you gotta ask; hire it done! We'd like to see you as a regular and not a "in memoriam" thread!

What are you going to use for the refractory insulation?

[Oliver St John Mildmay]

Very Safe A Good Answer Steve, But Thats Not Really Progress.

We All Learn Somewhere, and often seemingly nieve questions can mask impressive intelect and ability, and not seemingly be as obvious as all that, but just filling gaps and assuring and drawing on knowledge. EveryOne "starts" some where

Buzzkill, Thanks for the advice, and but will probably work it out. Just thought I'd run it by everyone. Yes have done a bit of reading.

Erm, i was gonna get an old barbeque, mould a plaster of paris and sand mix around, and possibly create a sealing insulated lid, wrap the previous ebay heating element to it, around the steel nails (its not gonna get above 1400c) and have a hook system for a 3 kg ish crucibal to suspend in. The only thing I wasnt sure about is whether the plug directly on the heating element will fuse, trip the house electrics. Or whether a resister is needed ?!?!

 

Thanks Thomas, lol, no I dont want an early crematorium lol haha ha

Plaster of Paris and Sand 

Edited June 25, 2021 by Mod30
Excessive quoting

[ThomasPowers]

But if we post something here; the whole world can read it---not just the "smart" people.  Here in the USA you can be sued for everything you've got if someone follows your instructions and gets hurt; so we tend to avoid the "Can I give my teen age son a case of beer and the car keys for his 14th birthday?" types of questions. What do you learn playing Russian Roulette that you could not learn refraining from playing it?

Molten metal is more dangerous than solid metal much hotter than the molten stuff!  I took an out of hours casting class from a Uni (back in the early 1980's) to learn a lot of the safety aspects, ( I cast furniture for knives using my coal forge as the heat source.)  I strongly advise finding a "backyard metal caster" and working with them.

I also do NOT advise using plaster of paris for forges, kilns and foundries. IMNSHO, saying that you will be using it seems to cancel any suggestions of prior investigation, intellect and ability. 

[Oliver St John Mildmay]

Yeh, that's the thing with the internet, .... it's pretty public, especially many forums. Now who's showing erm, we'll call it nievity.

One, many, can be sued for speaking, locked up for all all sorts, killed harmed in many ways for many reasons, yet being honestly rewarded for achievements (the sort of purpose of this thread) can be infinitely more difficult. You wanna agree with the world as it is, cause at "worst", deaths the outcome, no probs, that's you're choice. Personally I think it needs a lot of improving. 

Give some beer and car keys to a child well yep theres not much experience, however give a weapon to an adult (quite a popular occurance on the planet - army, police, criminals, no i dont have weapons apart from kitchen cutlery which i reserve for food) and not only do many use them but some actually donnate their life to it. No thanks to the Russian roulette or avoiding doing things cause of the risk. 

Nope I think I'm gonna attempt this task.

If you think me using plaster of paris and sand implies no sense of prior knowledge, ability, investigation, and intelligence ... I'd say 3 if not 4 of those show your ignorant wrong assumptions tbh, no offense meant.

lol, does anyone know or have an opinion to fixing a plug onto the heating element, lol?

I TAKE FULL RESPONSIBILITY FOR ANYTHING I TRY OR GET SOME ONE ELSE TO ON THIS TOPIC.

Maybe I'm better off working it out lol hahaha

 

Edited June 25, 2021 by Mod30
Excessive quoting

[Scott NC]

[Frosty]

Welcome aboard Oliver, glad to have you. Have you read the Dunning Kruger papers? I HIGHLY commend them to your attention, what you're saying you're more than smart enough to figure out without learning from others is potentially disastrously dangerous. You do not know enough about the subject to know how little you know.

Plaster of Paris and sand is a LOUSY thing to subject to fire, even a campfire. You see people recommending it who have as little knowledge and experience as you. Blind leading the bind. Yes?

You can go ahead and tell me I'm "attacking" you, I'm not.  I'm trying to save you from potential: disfigurement, crippling injuries followed by long days in the hospital and therapy, if you succeed in burning the house down as well I surely hope nobody is asleep. All you'll be doing is screaming in pain, maybe loud enough to wake up the family but I wouldn't bet their lives on it. 

Thomas is speaking metaphorically, we've seen too many know it alls present plans as dangerous as yours. He's just hoping you'd be responsible enough to recognize the danger you represent to people who don't know enough to NOT do what you propose.

Yeah you can SAY you take full responsibility. You can SAY anything but are you going to pay their hospital bills, drive them to appointments, hold them when they're crying in agony, work with them daily doing PT? Bet you're more likely to say LOL ha ha ha ha. 

You obviously know too much for me to be of any help. Good luck.

 

[George N. M.]

Oliver, many of us here have been messing about with hot or molten metal for many years.  I would guess the cumulative experience would be measured in centuries, if not millennia. And during that time we have made lots of mistakes, seen and heard about more, and some of us have been injured.  And, we have seen folk come onto the forum who are proposing to do things that we know are dangerous or the person clearly does not have the background to recognize that they are getting into deep, fast, and cold water very quickly.

So, we do not want to see people doing things that have a high probability of injury to themselves, others, or property.  So, we are apt to warn people off things that we see as unacceptably risky.  It is up to anyone whether they take the advice offered here, or from someone in person, or divine guidance.  In the end, everyone is responsible for their own actions.

As to your proposed furnace, I have to agree with others that plaster of paris is not a good choice for high temperature applications.  It has a fair amount of water incorporated into its structure which causes structural failure when heated above 100* C.  Whether tempering it with sand will eliminate or reduce that result I do not know but if it were me, I would use some sort of clay/sand mixture rather than plaster of paris.  That, IMO would have a higher liklihood of success and a lower probability of failure.

But do what you think best and good luck to you.  Let us know whether or not it all works out.

"By hammer and hand all arts do stand."

[Oliver St John Mildmay]

Frosty, nope, thats your assumption projection, that I'm saying I don't want to read or experience others knowledge, probably very impressive. What I saying, is I don't want to do a degree, to melt a few aluminium cans.

Nope, not really leading anyone or blind leading blind. Thats why I'm asking questions strangely.

Do you recommend sand and plain cement as a fire retardent lining? 

Nope not saying your attacking me. Or looking to burn down houses, or people, been there with being burnt, or harm really at all. And nope not into the screaming in pain.

Nope .... not a know it all ..... that's why I'm asking the question for advice. Nope not particularly being irresponsible. I havent proposed any thing to anyone ... ive asked for others to propose about wiring. What is dangerous about what im saying .... cause it will envourage others to make a forge that wont might not get it right? I sort of see the problem. 

Errr Im proposing I MAKE A FORGE ..... not others. Surely this has been projected on this website Quite A Few Times.

Yep .... it's certainly turning out easier to DIY it than get advise lol 

 

58 minutes ago, George N. M. said:

Oliver, many of us here have been messing about with hot or molten metal for many years. 

YEP NO FAIR ENOUGH tbh, no joke ... Very Good And Quite Right Perspective And One That Should Be Projected. Thank You For Your Amazing Care <3

Gosh for a moment I thought I was getting enough heat on the forums to melt the cans tbh lol

Edited June 25, 2021 by Mod30
Excessive quoting

[Scott NC]

  I don't get it.  If you want to melt metal for a hobby just build a gingery style foundry set up and use the proper ppe and safety considerations.  Learn how to mold using the right materials.....  It may not be the most whiz bang way to go but it gets results and you learn a lot on the way.  Easy way to get started.

[Frosty]

3 minutes ago, Oliver St John Mildmay said:

Do you recommend sand and plain cement as a fire retardent lining? 

I don't have to assume anything, I enjoy extraordinary reading comprehension and you're saying these things up front. When I'm projecting my friends here contact me on the side to let me know I'm going off the rails. 

Sarcasm is going to win you help how? Has it EVER worked for you? 

Do some reading and get back to us, you've already dismissed solid information about what to look for and where to argue with folk who just don't want to see you a Darwin Award winner.

I'm not going to argue nor play silly buggers with you. I have better things to do. 

The above post is another piece of sound advice.

 

[Oliver St John Mildmay]

36 minutes ago, Nodebt said:

  I don't get it.  

Yeh thats pretty much what im doing tbh. Although electrical forge ... dont wanna XXXX around with gas.

 

Well if you get contacted when youre going off the rails, I'd have messages coming in every half minute lol (severe mental health problems - on meds, great therapy, got a mental health team, never done anything mega wrong physically, anyway).

Scarcasms well useful, really good at putting a perspective across, and or clearing the way.

Well thats very kind, really is, very caring, thank you .... yep not wanting to necessarily join the Darwin awards particularly either tbh.

Better things to do ... definitely better.

Yep advice noted.

Sooooooooo back to the plug. The way Ive got it worked out, the heating element might add enough resistance to not fuse the plug / electrics?!?! Or if it does, just adding a simple resister of the right resistance (yes calculated) should suffice in allowing the heating element to go very hot with out causing danger or damage to living areas.

I'm not going to be doing this in my house or front living room, lol. Back garden, when not raining.

Edited June 25, 2021 by Mod30
Excessive quoting, language

[Steve Sells]

I hold a Masters rating as an Electrician,and have been licensed since 1984, I am not going to be able to train you to be a responsible wiremen in a few posts that you wont read anyway.  This is not a wild statement as you have proven this by ignoring the posts you were directed to read when you joined, and you also ignored the PoP and Sand mix threads you would have read if you really wanted to know about it

[Oliver St John Mildmay]

I've just had loads of my posts taken down / edited by mod42 with an email about mod warning.

With this comment;

... I just edited every one of your posts, of excessive quotes, If you had followed instructions when you joined, and read the Read This First post, you not only would have known to trim your quotes, but would have read the pinned threads like the one where it tells how bad of an idea Plaster of Paris and sand mix is ....

 

 

Excessive quotes allows those reading to comprehend the logic of what comments refer to what. To see who is actually clever and coming out with stuff that's right .... not just believing those most influential. 

No one else has trimmed their quotes?

Yeh I'll read that in a mo.

errr are you lot serious .... this is what you call a helpful forum on practacalities lol

If you have a masters as an electrician ... surely its an easy answer?

I did want to know about it .... its just easier to ask and get told isnt it ?!?! 

[Frosty]

Okay, I have a better idea of who I'm dealing with now. I'm a traumatic brain injury survivor and have a raft of issues of my own. Mistakenly thinking people are deliberately giving me trouble is one that's hard to recognize and you young sir are leaning on that button. 

Your "explanations" come across as excuses and smart Alec remarks. You were successfully starting to get to me and YES I always have better things to do than let someone get me going if ignoring them is an option. 

You are mistaken. Sarcasm is NOT useful behavior, it does not "put perspective across." What it does is put people off of wanting to help or even deal with you. It does exactly the opposite of "clearing the way." It closes the way.

Right now in your last post YOU ARE GOING OFF THE RAILS.

Yes, anybody abusing the quote function gets edited and a message as to why. The message is common courtesy and YOU agreed to abide by the rules when you subscribed. Quoting a single sentence to respond to specifically is NOT quoting entire posts directly above. Especially not for the purposes of being snotty.

If you wish help YOU have to want it enough to stop the pity party games and talk straight. If you REALLY have a mental health team then you should have THEM subscribe to Iforge so we can give them simple instructions and HOPE they're followed or respond with intelligent questions.

I'll do what I can to help but YOU have to do the work, I can't reach through the screen. All I can do is tell you straight it's up to YOU to learn. 

Your choice.

[Oliver St John Mildmay]

18 hours ago, Frosty said:

Okay, I have a better idea of who I'm dealing with now. I'm a traumatic brain injury survivor and have a raft of issues of my own. Mistakenly thinking people are deliberately giving me trouble is one that's hard to recognize and you young sir are leaning on that button. 

Your "explanations" come across as excuses and smart Alec remarks. You were successfully starting to get to me and YES I always have better things to do than let someone get me going if ignoring them is an option. 

Ok, glad you see the light. Yep issues ... definitely issuish. Nope not mistakingly thinking that people are giving me issues .... i comprehend the safety perspective. Just not mega into getting electricuted or tared and feathered and hung over it .... death the right way is still pretty unappealing tbh.

errr if you think my smart answers are wrong, im sorry, i couldnt really give a xxxx, i think a lot about popular safety and evolution is wrong. I'm not trying to change you, and im mostly happy with who i am and who yourselves are, and are modifying working on the other bits of me at the moment that arent quite right.

Its not my fault popular society has particular bias to what personality traits are acceptable and should be popular and or appeased, scarcasm being one. If your value is not to like it, or if you have an irrational bias against it ..... I'm sorry thats your popar obcessive style deludednesses. 

I see alot of quotes have been removed .... emotional "harmony" as the priority ..... errr yeh ok. Too much disk space? Or enlightenments now in the same category as scarcasm ? I look at LOADS of websites .... and forms .... they all have terms, rules, ways etc etc .... many i dont agree with ..... and i would never get to post a thing if i was to have to reference the rules each time i post.

WHAT IS NOT STRAIGHT TALK ABOUT; WIRE RESISTOR PLUG

Yep Im trying to learn very kind thank you

IVE TRIED REPLYING TO THESE COMMENTS AND NOW I CANT REPLY WITH OUT THE QUOTE BEING INCLUDED xxx LOL IT DID IT AUTOMATICALLY AND WONT REMOVE <<<< TRUTH IM NOT DOING IT ON PURPOSE 

Edited June 25, 2021 by Mod34
Edited for inappropriate language

[Oliver St John Mildmay]

hi 

i'll read the roles and get back on line another time 

thanks

laters

take care stay safe 

oliver

 

[Glenn]

Your quotes have not been removed, your quoted HAVE been trimmed.  There is no reason to quote what we just read, or to quote an entire post when you refer to only a small portion of that post.

Please read  The quote feature.

[Ted Ewert]

Hey Oliver, 

Seeing that you have read all the sound advice here, and still persist on your path to trouble, I'll give you my two cents.

I've also built an electric oven. I did it first the way I thought should work, just as you are determined to do. Then built it again using these guy's advice. It cost me twice as much time and money in the end.

I'm just as pig headed as you are. The only thing I had going for me is a thorough understanding of electricity and electronics. 

You need to know how much resistance you need in your heating wire to avoid overloading your circuit. You also need a switch which is rated for the amount of power you're drawing. That needs to be mounted in a suitable enclosure. 

You can't just connect copper wire right on the heating element either because it gets real hot. You need a way to solve that problem. 

I could go on and on, but I hope you get the point. Just wiring it up and plugging it in won't work. There's plenty of information here to get you started and lots of knowledgeable people to answer questions. 

[Oliver St John Mildmay]

Glenn, yep comprehend that just refer to the person or comment.

Ted .... 2 cents brill.

Yeh Great advise. Thanks. Yep thought of most of that and youve just inspired a test of the resister wire with a voltmeter to determine mains compatibility.

And youve all just motivated calculating the work first - BRILL THANKS ACE 

[Steve Sells]

13 hours ago, Oliver St John Mildmay said:

If you have a masters as an electrician ... surely its an easy answer?

I know how to teach a 5 yr old how to use a flash bang grenade, its also easy;  but I am also smart enough to know not to do so,  for the same reason I wont give wiring instructions on an open forum to people that wont follow directions

[Latticino]

Oliver,

As many have already tried to tell you, you are headed down a bit of a dangerous path.  You need to be prepared for at least the following:

1. Matching the overall draw of your furnace with the electrical circuit it is connected to.  Most likely you will want to use a 220 V (or whatever the equivalent voltage is in UK) and on the order of 30 amps.  This kind of power is sufficient to cause you significant damage if used wrong.
2. Controlling the power output so you achieve the temperatures you want without either overshooting or burning out your elements.  As previously noted this likely means that you will want to use some form of temperature controller.  Most of these will require some form of interposing relay or contactor to allow the low voltage controller switching to cycle the high voltage coil power.
3. Coil design: Wire size, length and method of suspension are critical.  Coils will sag when hot.  If they touch each other you will screw up your circuit.  You must suspend your coils without connecting them to a conductive shell.  You need to design a heating coil assembly that is circuited in either parallel or series to match the resistance with your available main power.  There is a reason coils are used rather than just straight wire.  Do you know why?
4. Service wire:  correctly sized so the resistance there is low enough to not heat that up (like your coil) and start a fire.  Electrical code is your friend.
5. Circuit selection at main:  correctly sized so the draw doesn't pop the breaker or burn out the power wiring to your equipment connection.
6. Door switch:  both molten metal and the tongs used to manipulate a hot crucible are conductive.  You should have a safe and reliable way to keep the power shut off while the door is open.
7. Shell Design:  For efficiency you need decent insulation.  For safety it needs to be able to take the anticipated temperatures.  For convenience it needs to be able to easily support the coils.
8. Door design: again, frequently overlooked, but you need to plan how to make a door and where the hot side of same will be while you are trying to move a crucible full of molten metal

I have found the design information in the following to be a great guide.  Some of the systems are a little dated, but I've built gas forges, glass furnaces, annealers, hot pickup ovens and heat treat ovens using similar strategies:  https://www.joppaglass.com/homepg/Joppa.web.Product_Cat.2018.pdf  (if the TOC don't allow this informative link, just go to Joppa Glassworks and look for the downloadable PDF).

Right now what you are proposing is analogous to sticking a fork into the electrical outlet in your house.