DIY Raspberry Pi Temperature Control for Kiln Foundry

[@hugueshenrion6642]

KZbin is such a lottery. Your videos are as awesome as any other video of the big youtubers from 2016 and yet you have so a fraction of the subscribers they have, You must have put a lot of work into making them. Thank you for your content!!!

[@MrMilarepa108]

I totally love your videos! Especially because you're great to listen to, because you show the mistakes, because you reference your sources well, you don't go too deep into the technical parts of the electronics but still provide all the info through the links. Your lathe project is amazing, it's hard to believe that you only have 10k subscribers. Hope to see more in the future!

[@centurialinc]

Cool project and a well done video! You out did yourself this time Cressel! Thanks for the plug too. Can't wait to see what you come up with next. Best Matt

[@xxgunnery]

The skillset required to make this project is awe-inspiring! Fantastic video and an excellent design. Big props to you for sharing this!

[@paularber605]

From using color charts to guess the temperature to digital precision a quantum leap. Its neat to have the temp graph of the melt Great job. Now you too have sufficient graphite to cover your melt and prevent oxidation.

[@tristianjaden1389]

not sure if anyone cares but if you are stoned like me atm you can stream pretty much all of the new movies and series on InstaFlixxer. I've been streaming with my gf these days =)

[@tristanari4343]

@Tristian Jaden Yea, I've been using InstaFlixxer for since november myself =)

[@Geeksmithing]

Dude, this was super cool! $10 Kiln? wow, what a steal!! Great project!

[@mountainmanfab]

nice work and one helluva learning experience. I need to look more into the pi and arduino boards as it seems theres a lot of nice additions I could add to my "toolbox" lol....still a bit oldschool tho and was feeling perty cutting edge when I hooked up a cheap PID a couple yrs back.With accurate temp control you will have much better pours and have the added bonus of being able to use the kiln to heat treat your castings and /or anything else that reguires timed stages at certain temps....and before anyone says you cant...yes you can heat treat aluminum at home as well as steel/etc...most metal supply places will show heat,"soak" and cool periods if you you look up the specific alloy...hell with a top opening kiln you can even furnace braze and do things under inert gas if you take the time to seal it up a bit and use the displacement method(gas cylinders can get a bit pricey lol)

[@frepi]

Anyone with a garage so clean is clearly crazy

[@highbridgepottery8251]

This might be just what I am looking for, currently in the middle of a similar project for a pottery kiln but stuck with the logic to control the temperature rise. Need to have a look at your code. Thank you for sharing

[@ianbottom7396]

Nice job. Material properties relating to sensible and latent heat are a very interesting subject with relation to energy input and change of state. Incidentally there was a small error you made there in describing it as latent heat of vaporisation, the state change is solid to liquid so the relevant term is latent heat of liquefaction. If you’re interested, it is possible to calculate the energy inputs, you need the specific heat figures for both the sensible heat and the latent heat of liquefaction. These combined with the weight, the initial and final temperature can calculate the total energy in kJ, and Joules/Seconds gives you watts, so you should be able to calculate fairly closely how long and how much energy you need for a given mass. Don’t forget that if you continue heating after liquefaction you’re going to be continuing to add sensible heat and if you added enough you would eventually be having to consider latent heat of vaporisation.

[@Cactusworkshopchannel]

WOW!!! totally cool system!!! nice job with the steel stand and the board and everything! great stuff :)

[@Streamcatcher]

Hi, great project and video. I am looking to create a kiln with a controller which I can program on my computer of smartphone by means of a graph editor/viewer. This to overcome the very outdated and user unfriendly pid controllers. Your project shows great potential. My oven needs to heat slowly in steps of 100 degrees an hour and stay for at least an hour at 850 degrees. I use a J thermocouple for this. Do you have any tips for beginners or ready made parts and software which I can use/buy for this? Any help is much appreciated! Kind regards, Sébastian

[@MichaelRuwurm]

Great build, do you have a dedicated button for stopping / starting the raspberry pi, or is it via software? I guess an implementation of a two point thermostat also allows you to temperature treat steel in your kiln.

[@Makercise]

The dedicated button is in the openhab interface. If my wifi router or openhab server dies I could not start the kiln. I can stop it with the rotary nob. I want to do some heat treating annealing eventually. I need a better temp control like a slow pwm driven by a PID.

[@alandavis6429]

Don't use lifting tongs to pour, they are only for taking the crucible out of the furnace. You put your pouring frame on the floor with a face warmed insulated brick in the crucible ring, you put the crucible on the brick and lift the pouring ring and engage the holding clamp bar and lift the pouring frame. Doing it the way you are runs the risk of crushing the crucible, dropping the crucible and you are chilling the crucible You can't pour safely with tongs and your hand is downhill from the molten metal.

[@btomas225]

So the rising heat from the kiln to the ceiling of the garage is not a fire hazard? I have a kiln I just converted and I'm weary of how/when/where to open the lid, when at around 1300F. for aluminum. I lack that practical perspective.

[@frangerhawer]

Hello, can you please tell we what is the thermocouple you are using? I have trouble finding one rated for more than 800 degrees Celsius. And what is the tube holding thermocouple made of? I also have electric klin foundry powered by 240V with the same heating wire as yours and I am looking for good thermocouple to use with MAX31855, Your project looks great and I am aiming to reach your level of professional-looking foundry :D

[@Makercise]

www.mcmaster.com/#7979A18 for gouging electrod used as shell tube. www.mcmaster.com/#3859K44 for type K TC.

[@frangerhawer]

Did you have problems with burning your heating wire before you installed temperature control? I have similar 2000W heating wire and without watching over it it burns and break from the heat. Do you control relay on the heater by looking at the crucible temperature and the klin temperature is plotted just to compare them?

[@Makercise]

I haven't had any issues with the heating wire burning out. I think it loses too much heat to get hot enough. Initially I was controlling on the crucible temperature. Now I am just controlling on the ambient kiln temp. I am glad I compared them since I could see the metal flat line while adding the latent heat of fusion even though the ambient kiln temp kept increasing. They are both pretty close once up to pouring temp.

[@frangerhawer]

so it may be enough to use only one TC to measure kiln temperature and try to keep it at the level slightly above melting temp.? Can you tell me what kind of wire are you using? maybe mine is just too thin to withstand larger temperatures.

[@Makercise]

Michal Herzyk i used 20awg with a ceramic fiber insulation rated to 2200F inside the kiln. that is unnecessary though. i use 24awg with fiberglass insulation rated to 900f outside the kiln. this connects directly to the main ambient TC bent up through the port. the connection is on the outside of the kiln. i got both the TC and TC wire from mcmaster carr.

[@billsaunders1879]

Great video. I wanted to let you know that your raspberry pi affiliate link goes to a book.

[@danielraeburn6461]

If I could double or even triple like, I would !! Bravo very impressive

[@Makercise]

Haha thanks. One share is worth 10 likes BTW. ;)

[@GibsonYouTube]

not one dislike, nice job man

[@ChrisMuncy]

Nice job Cressel. Have you thought about adding an indicator light that shows when the elements in the kiln are hot? BTW - I too an jealous of the kiln purchase.

[@Makercise]

+Chris Muncy +Chris Muncy I thought about having a bar LED to give an idea of how far along the temperature was. I decided against it because of having to mount it and add components. It would be easy enough to write a rule in openHab to flash the garage lights when the kiln is up to temp. One other reason I may want a light is so I would know when the elements are on and the kiln is warming...so I don't accidentally leave it on. My wife regularly has this problem with our gas stove, but her notification typically is delivered to me about 20 miles away from home on the way out of state. If I am not running the kiln, I unplug it and coil the cord. I can also use the nob to turn the elements off regardless of the controller state. Thanks for the question hope I answered it. BTW I'll have my wife look out for another kiln for you and Wes ;)

[@ChrisMuncy]

Tell your wife I love her lol.

[@Makercise]

+etienne nel no worries I respond to lots of variations. Comes with having an unusual name. :)

[@bulwynkl]

The overshoot could simply be because the aluminium is melting and it take a while to get enough melt to wet the thermocouple housing.

[@willemkossen]

Such good work! Nice!

[@damirdze]

You could achieve all the functionality with an esp8266 instead of costly pi.

[@dejavu6938]

How many watts has your kiln? And how many time do you neen to heat it up , to melt the aluminum?

[@Makercise]

2400W. I have since required for 240V

[@Makercise]

It takes about 4 hours to melt aluminum.

[@taylor5263]

im new here and i love your videos theyre very professional. how come you upload so infrequently? thanks

[@Makercise]

Day job, house work, spending time with my wife and son. The twins we have on the way will be awesome but won't help me expedite any videos...at least not for many years. Also the videos with electronics and software seem to take longer generally. I wish I could get videos out more frequently too. Thanks for the encouragement.

[@taylor5263]

fair enough, thanks for the reply looking forward to future videos and good luck with the twins :)

[@معلومةجديدة-ش8ز]

عمل رائع و محفز شكرا لمشركتنا و افادتنا واصل

[@wdanieldinsio]

How do you have this much time on your hands?

[@Makercise]

William Daniel Dinsio at the time i was a branch manager at an engineering firm. No idea where i got the time. Now i do this full time.

[@Mad-Duk_Machine_Werkes]

Yes, you'll realize - you can NOT run anything thats high amperage draw on any sort of extension cord, it will make the cord hot, melt plugs, trip breakers, ect - theres formulas involved with amp and voltage drops over distance and the need to run larger wire for longer runs- but for something like that kiln I would say: I wouldnt go any more than a 10 or 15 ft cord of at least 12 or 10 ga wire (stranded) and then I would NEVER use any extension cord, AND I would wire a dedicated outlet, just for that Kiln use. with at least 10 or 8ga wire back to the breaker box, depending on how far away it is (sometimes you can ask an electrician, or occasionally the guys at Home Depot or Lowes in the electrical aisle can tell you the size wire you need for a 20-amp circuit for an outlet thats "X" distance from the box! either way it should be dedicated on it's own breaker and not daisy-chained to a bunch of other outlets in the line......

[@Makercise]

Yes indeed. Your comment really caused me to reflect on my installation. I can operate the kiln at 5, 10, or 20A based on a selector switch on the unit. After Metal Lathe - Part 8, 7:00, I have been very aware of just how taxing the kiln can be. Based on that little incident, I thoroughly checked out the circuit. I pulled the receptacle I use out of the box and confirmed the diameter of the copper coming in to the box as well as replacing the 30 year old receptacle. There is only one other receptacle between the one I use and the electrical box, total 15ft distance. I also pulled the intermediate receptacle and confirmed the gauge of wire coming into and out of that box and replaced that one with a new unit. Further, I made a pigtail in that box so as to not rely on a daisy-chain to feed my outlet. A fortunate benefit of having open joists in my garage ceiling is that I can trace this circuit out completely. There are other receptacles downstream, but when the kiln is operating I can be sure it is effectively a dedicated circuit. Finally, I replaced the cord coming from the kiln, used a stranded 12ga cord with 90C insulation, and added a NEMA 5-20 plug. After those checks and upgrades, I used my IR thermometer to confirm the temperature rise of the circuit, especially paying close attention to junctions: the electrical box, the two receptacles, and the kiln wiring. They get warm, but not over 20F rise in temperature over ambient conditions. That got me to the point where I was OK with the kiln on that circuit. However, I will probably rewire the kiln so it works on 240V so as to reduce the overall current draw, but for now I will probably continue operating the kiln from this effectively dedicated circuit. During this video, I definitely pressed my luck with a 20A-rated extension reel. Although rated at 20A, its wall-wart circuit protector tripped after 45min at 19A. I still wanted to be able to get the kiln outside the garage. I made a 20ft extension cord out of 12ga 90C rated cable with again NEMA 5-20 plugs and receptacle. I am not aware of a reason why extension cords cannot be used for high current applications. It seems they could be appropriately sized for the application. NFPA 70E might have something to that effect, so please direct me to the section if its in there. I believe the X distance from the box calculation is to limit the voltage drop caused by a high load. In my case a voltage drop at my resistive load would decrease the overall current draw. Regardless, I have done voltage drop calculations and even with my 20ft 12ga home-made extension cord, I expect less than 3% voltage drop. So that is my rationalization for where I am at. Note that NFPA 70E actually limits cord connected load on a 20A circuit to 16A. Not sure if the code was different in that section when my house was built, or if cord-connected loads are grandfathered in anyway. Wow, sorry to write such a long response. Your comment resonates with me. I really like to understand what the code requirement is, then I am better informed about what is the best for my installation. Lots of ways to define best: facilitating future expansion, cost minimization, installation feasibility, return on investment, safety.

[@robfrost1]

Don't weld or grind too close to that nice paintwork, or... spotty paintwork.

[@azharothman8535]

interesting..

[@BlackBeardProjects]

Really a great project!!! Good job! I really would like to build myself a pid controlled eletic kiln to heat treat knife blade instead of using my huge and unprecise charcoal forge. Thanks for the inspiration :) also check out my channel if u want, I also did some aluminum casting! See ya!

[@ollininvincible]

Wow, just wow. 0_0