How to Temper a Graphite Clay Crucible for Metal Casting at home
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- Опубліковано 8 вер 2024
- I got a new crucible, but it's not ready to use just yet. First, i have to temper it! It's basically all the fun of metal casting, but without melting any metal. Doesn't sound fun? Well, you know what else doesn't sound fun? Having a crucible break full of molten metal because you didn't temper it, spilling it all over and burning you. Yeah. Think about that for a moment. Tempering doesn't seem like a bad idea anymore, does it?
To do this, I used hardwood lump charcoal and the improved mini metal foundry I built in an earlier video. The crucible is a #6 I think.
Anyways, i've gotten some questions about getting into metal casting, and tempering a crucible doesn't seem to be mentioned too often. I want to change that, because it's important.
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#metalcasting #foundry
You actually read my mind
I've been searching all day for this type of video about crucibles and I found your channel earlier today
Man you are the best
glad I could help!
I got the same crucible from PMC, and it didn't come with any instructions, so I wrote to them with about 10 questions. To summarize the response, it should always be preheated before use, and you should never add a cold crucible to a hot furnace (fire it up along with the furnace, or get it up to temp with torch before adding). Putting the metal in before adding the crucible to the furnace is "a very safe practice". Crucibles taken out of the furnace should be placed on a fire brick to resist thermal shock, but can then be left to air cool. Don't store in a humid place.
Thanks for the info!
Built the mini metal foundry 9 months ago and just started using it, made a few rookie mistakes haha.
Used a mini leaf blower for air supply and it's too strong with no variable speed. Blows hot coals and äsh into the crucible.
And i stirred the aluminium and made a huge chunk of dross😂
Cool bro I just got an 8kg crucible and wasn't %100 sure on my first firing of it , you make perfect sense when you say these could have been sitting in a damp warehouse😳so I'll definitely heat it empty first and as I said in my keg furnace vid on my channel this week I won't be melting with it until I have the proper pouring handle for it. New sub by the way buddy . Check my channel if casting and brass copper melting interests you , there's plenty of fails there aswell😬. Cheers👍🏻🍻
Thanks! You're stuff is pretty awesome, got any tips for melting brass?
Hey just wondering if I could use this to make a mini metal foundry
www.amazon.ca/gp/aw/d/B0149J01HY/ref=mp_s_a_1_fkmr0_1?ie=UTF8&qid=1489641206&sr=8-1-fkmr0&pi=AC_SX236_SY340_QL65&keywords=castable+refractory+cement
Paul's Garage my tips would be to overheated the brass so it stays liquid for a bit longer for a better pour . try cleaning the brass b4 ya melt so there's not so much crap on top to skim off ( I don't do this cause I'm a lazy bastard) glasses always wear glasses ! And as you know No Moisture-I lowered a room temp piece of brass into molten brass and the piece I lowered must have had some grease ,oil or some sort of liquid still on it and it made the molten brass bloody explode 😮. The brass exploded up through the small opening in my furnace lid (I'm glad that lid was still on) and some hit me in the face and even hit my roof which is about 9ft high. None actually hit the skin on my face two blobs hit my glasses and facemask I was using at the time, it happened so fast I couldn't even retract in time I stood there waiting to feel where else I would be burnt on my body because it splashed out everywhere and to my surprise it splashed all around me and none actually came back down on top of me or my clothes, I was very lucky and it made me make sure I always preheat any metals when submerging them into molten metals. It was very similar to a steam explosion from lead except three times hotter. Sorry no other real tips if you've seen my other videos you know I'm the one that needs the tips not you. You seem very intelligent when you talk about this stuff you sound almost like a teacher of sorts . I love your videos buddy keep em coming 👍🏻👍🏻🍻
The GreatBanger I use something very similar and it works great that stuff you have there would be ideal for aluminium and brass melting I would think as that's a couple hundred degrees lower than its maximum temp on the concrete. On the furnace I use it eventually broke down after a few months because I was melting copper and exceeding its temperature limit on the cement. If your just using it for aluminium I would think it would last a bloody long time . I would highly recommend cheap heat gun off of eBay that way you won't overheat the foundry too much and have a better idea of when it's ready to pour. I would think the high temp cement would be expensive because the stuff I used certainly was. Be sure to check my channel you'll see a lot of things I fail at so you'll know not to do them like me👍🏻
Paul's Garage hey Paul I also recommend A cheap heat gun off of eBay that way you won't overheat the foundry too much and have a better idea of when it's ready to pour. The one I use on my channel goes up to 1050°C and has saved me so much time and gas as it gives you such a better idea of when everything is ready to pour and how quick everything is heating up. The one I got cost about $44 AUS with free world post👍🏻👍🏻
You do not need to temper a clay graphite crucible man, thats a total myth! There's all kinds of variations, even some that suggest a 50/50 mix of borax and boric acid (which is ridiculous, because borax is just a salt of boric acid and in this case, it just mixes into a stronger acid by diluting the salts throughout the mix)... That particular suggestion was posted by a distributor... And it makes sense once you realize it destroys the crucibles over time (you'll buy more of them, sooner). Nowhere in our trade books does it state this, and if you ask around to different foundries (ones that aren't malicious to keep out outsiders out of it, because profit and work is slim and rare), you'll find you get funny looks when you mention borax; that's why.... Cold borax in a crucible? No harm... Heat it up and you have a corrosive honey. If you took a chemistry class, even in high school, that was one of the first things you should have been taught. Heat speeds up reactions.
Borax will decay a clay graphite crucible. It will literally melt it, layer by layer, every time you heat it up. You'll notice the wall is always coated in a melted glass-like substance, and you'll think its just borax, its not, its your crucible decaying. You'll notice pits and that it seems to be missing large portions of material, particularly at the bottom and on the sides where your typical fill line is. Eventually it will crack, but when this happens its usually when you pick it up (extremely dangerous scenario), or leave too much metal in it to cool. Raw heat doesn't disturb it too much.
This messes up castings as well; especially gravity casts, as it contaminates the pour and promotes oxygenated metal to form (not just 'oxides', I mean oxygenated metal, the reason we use degassers). Acids and salts will bind to the metal, leeched from the decaying crucible and the acid causing it, which discolors the metal's surface, makes for higher viscosity (bad pours), sometimes even trapping blobs of melted crucible and borax soup in the mold, and causes it to tarnish much more quickly after polishing (to counteract this, degassing chemicals are used, but normally these are not needed unless it has to be a specific alloy, usually only done in aluminium in that case.
I'm on my 11th crucible after 4 years, and not a single one has cracked, and this is with me dropping in 10-12 pounds at a time, out of the box, placing it into the forge cold, and blasting the hell out of it with a hybrid propane torch that gets hot enough to melt kaowool. I still own 8 of them from 3kg to 12kg, and the only 3 I've lost were due to decay... Surprise... they were the ones where I was using borax and boric acid as a flux and anti oxidation method for high brass, before i knew any better.
Want a flux? Use lead.... Dont want it to discolor? Well then fork out cash for industrial chemicals or rework your mold plumbing while pouring at a higher temp (too high makes hundreds of tiny bubbles inside most molds, even when degassed, so be careful).
Want an anti oxidation method? Throw some brown charcoal on it, or ash, like we have been doing since about 2800BC, (ash is lighter and thus harder to get in there because of the heat draft, but works wonderfully). There are also commercial solutions here bu they are pricey if you don't want to destroy a crucible and really aren't worth it even of you have a large crucible, like a 12kg (which is pretty small still, some of the crucibles at the foundry are 3 feet wide (about a meter wide for the sane people over in the EU).
I don't know who started the tempering thing, but its bullshit, and the suggestions I often see written below them are just as absurd. It seems we live in a world where you can just make things up without testing them, post them on the internet; and because theres only like 1 in 100 of you who actually do cross referencing, or know what that term is for that matter, everyone thinks its true... Seriously its gotten so bad that we jokingly call them "flat casters" around here, after the "flat earth society".
So instead of tempering the crucible before use, can I just place the graphite crucible into the furnace and leave it there for 15 minutes to get it bone dry, then place my aluminum or copper and wait for it to melt? I am concerned about the part about splattering due to moisture in the crucible, especially since I live in a 90%+ humid area.
Currently cross referencing now. Do you reccomend any types or brands of crucibles? I'm planning on doing aluminum, zinc, brass, bronze and lead. Is contamination an issue?
Do u know how to make clay graphite rod , I am need of clay graphite which can with stand
2000 degree centigrade pls help us
@@uberLejoe morgan salamander, goes up to cast iron, defently good enought for bronze. anything lower you can get by with generic low cost. but as it is with everything in life; if you want milage, you gotta spend the extra cash. just get starting, don't overthink to much and just be wise about safty. you still can dial up a notch later...
Dev Wolf he didn't use borax. He just heated it to drive out moisture. You shouldn't shot from the hip, you miss this one.
I used my clay/graphite crucible with the cans and the dross/crap that stays behind after the pour and cool down pulls out with ease. It stays pretty clean actually.
+darktideryezing that's interesting. The junk left behind in my crucible also comes out nice and clean.
Cooking mine in the oven now. Not a very pleasant smell in my house at the present time. LOL!!
Could be worse, could smell like my cooking!
I noticed that i have the same jacket as yours. i bought it when i was in UK. 🤣 nice video and thank you
Im done with metal crucibles burning out too (fire ext, small camping propane tanks), gonna have to order one. Thanks!
+schel sullivan clay works so much better in my experience. Just don't drop it lol
I know this isn't strictly related to this video and I'm not sure if anyone suggested this in one of your other casting videos but when you cast when you remove the wooden dowels if you remove some of the sand around the hole and form a dome shape the aluminium flows more easily in to it and makes it more controlled reducing the likeliness of burning your flask or spilling any reducing wastage hopes this helps and love the content. Subscribed
Thanks for the tip! I've seen people doing that, i don't know why I didn't try it. I was kind of in a rush i think so i didnt' bother, and i ended up burning my flask. oops.
Thanks this video really helped because I just blew up my first crucible
How did you blow it up? How long did you use it for?
@@wonghiulan2961 We can't say for sure, but I would think it was their first 1st Crucible ever and probably the first time used
So glad I saw this
Good explanation, will follow this method. Thanks.
He paul, if you need to make a quick melt and don't have a graphite crucible on hand. You can use a steel coctail shaker. If that gets a hole in it, a temerity fix can be steel wool and melt it on the crucible to fill the hole. keep up the good work!
I like these videos, I find them very entertaining to watch and also quite informative.
Keep up the great work :)
Thanks! I will!
Ordered mine off amazon, first thing i did was threw it into my forge and filled it with aluminum. Been through over 25 fires and a couple with copper and still good as new.🤷🏼♂️🤷🏼♂️
A great tip is ALWAYS place it on a piece of cardboard. This will burn up and leave a carbon behind. This keeps the crucible from sticking to the plinth block. If it does try to stick, twist the crucible on the block and it will usually come off. Once that block is stuck, its next to impossible to get off. So in short, ALWAYS ALWAYS set a hot crucible down on a piece of cardboard, expect some flames.
That's a good tip, i'll keep that in mind. I usually put that round grill grate on the ground to suspend the ingot tray and stuff above the concrete, but I didn't think about cardboard. The carbon would prevent sticking but also carbon is a good insulator, right? It could help prevent too much heat from escaping through the bottom of the crucible.
Paul I use a steel crucible made from 3/8 by 3x3 tube to melt aluminum. If you get the steel to red hot before you add the aluminum, it doesn't leak through
interesting, thanks for the tip
hehehehe love the commentary, I have a clay graphite crucible just like yours, bought it about 12 years ago and never used it. Now I have need to implement my nefarious aluminum plans... so thanks for catching me up! Time to go melt stuff! But no blowing up....'cause that would be bad.... mostly. :P
+P. J. Galati yes! Be sure not to blow up! Aluminum is fun to use, I'm sure you'll have a great time
I have seen steel - stainless, no less - go leaky during a foundry session at a Portland Gears show circa 2015 or so.
I assume that the oven temp is 30 deg F, not 300 deg c? Thanks in advance.
Great video, Paul. Congratulation on hitting 1,000 subscribers! I remember when I commented two weeks ago and we were talking about hitting 900! Anyways, I enjoyed the video and can't wait for your casting videos to be up, so I can try them in my foundry!
I use a cast iron pot that I found in a junk shop. Works good for melting cans.
Sounds like fun! These days I run my burner on maximum power and now that I know it can melt cast iron i'm hesitant to use anything other than a clay crucible
I use hard wood to melt aluminum in cast iron pots. I tryed coal but it melted the pot. In aluminum i will use cast iron. Now for brass and bronze, i will use a crucible,
Good videos I like the average joe aspect . Not claiming to be a expert. Showing mistakes as you make them just like the rest of us could make . keeping it real and fun.
Glad you enjoy the videos! I'm absolutely not an expert, if i edited out the mistakes I wouldn't have any videos left lol.
When the crucible is made it is fired in a kiln. There is a point where the whole load of crucibles are red hot. And they all cool slowly. The same as your process now. So would that not mean your crucible is already annealed?
It can still blow apart don't ever forget that. Lol I once, twice sat mine down on the concrete patio. A fraction of a second after I picked it up the patio popped. Spit rocks away from me and the crucible. I froze for 2 seconds and put it away because it wasn't dripping. Phew.
Great video, congrats on one thousand sub!
Rodrigo EspecialesyAgradecimientos thanks!
Rodrigo EspecialesyAgradecimientos
Paul's Garage
Wow!!! 😳 I totally missed the Subscription count skyrocketing past your first 1,000!!! Keep up the great work and I'm sure that those numbers will only get bigger even faster!!! Congratulations on your first 1K!!!
Thanks! i'm a bit surprised myself!
Rmiq
I like how your day is measured in meal times
Does anyone else see the laughing clown in the mushroom cloud at the end of his vids?? Was that intentional?? 😂😂
thank you, this video actually helped me out immensely
glad it helped!
I think I got the exact crucible as yours (number 3) and the foundry I made with refractory cement has exactly the same space around the crucible to add charcoal, but for some reason I cannot manage to get the crucible hot enough for it to become "red hot". I have my hair dryer blowing at an angle to help air flow around the foundry but seems like only the bottom charcoal gets hot while the top ones do not heat as much, causing the crucible to only get red at the bottom :(
I have melted holes in pure steel pots and cast iron. Im getting a load of hard cured wood because a cast iron crucible lasted 2 years when I used wood instead of coal firing I have a no 8 crucible but the tongs are holding me back I want a no 10 tongs for 2 people to lift out of the furnace for hotter melts
yaaaay 1000 subs!!!!!!!!!!!! great video Paul, Keep it up.
I LOVE your videos! Keep up the good work!
Thanks!
Do all crucibles need to be tempered?... and do all crucibles need to be tempered if they've already been tempered if they sit on a shelf without being used for a very long time? (Are they hygroscopic at all?). Sorry it it was mentioned in the video. I watched it twice, but don't recall if that was mentioned specifically.
You'll be much happier with the graphic. It's easy to clean out so don't worry about using cans or other extruded AI parts.
eviltwinx the cans were terrible, mostly for the smell. I worry that some of my neighbors don't appreciate burning plastic lol.
Hey Paul,
To improve airflow you could glue a tube or so to the outside of the small bucket, in the hight of the airblower if you are making the foundry. If the cement dried u can get the tube out, then the air has a way to go around. Don't pick a tube that's to big, otherwise the charcoals will go in there.
Hope it works😂
Jonatan Den Breejen that's a good idea, I might use that in the next furnace build
There's an old saying; ''One picture is worth a thousand words.''
yeah put the paper bag filled with charcoal right next to the furnace! Great Idea. Safety with paul
That is nowhere near the worst thing you would see if i had a wide angle lens on the camera...
If you want to melt steel it is best to use a pure graphite crucible because the clay graphite crucible begins to vitrify the steel casting temperatures and it can even stick, so it is best to use a pure graphite crucible for the steel casting.
thanks for the tip!
Cast iron skillet works very very well there 10 bucks at dollar store or wally world and I havent had one fail yet
For my charcoal furnace i blow the air up from the bottom, gives a very even burn.
Hey Paul, very entertaining video. usefull info as well.
Thanks for sharing.
Regards Shayne......
Great video man, very informative and not a detail left out do you have a video on how you made that furnace I’d love to see how you did that and make that for myself
hey nice video. feeling more confident about casting already.
Can the steel that the aluminum dissolves and soaks up contaminate the aluminum and cause any problems? (weakening it, changing color, less hardness, more brittle, galvanic corrosion or whatever that's called when dissimilar metals are in contact... or other things like that?). I'm asking, because I truly don't know any would appreciate anyone's opinions. I don't know much about casting and would like to learn what I can. There are many problems like this that people can run in to if they don't learn in advance. Like with carrying a firearm for self defense, it's better to know what you're doing before you start, because if you know nothing about guns or safe/responsible handling, you might cause an accident.
Oh my God the same situation you had with the hair dryer is the same one I had lol.
Loved the Video! Great information!
lolz! love the random subtitles! also, lots of useful info like the graphite/clay crucible I have (the same one off amazon!) is actually not good enough for cast iron :( was going to be my first attempt at a 3D printed stator for a 3D printed brushless 600W motor from the internet.
yeah cast iron usually needs a different kind of crucible, also MUCH more heat from the furnace. I doubt i'll ever get that stuff to melt.
Hi PAul
Got you link off bigstackd I have built a propane burner furnace will the temper process be the same oven for an hour then furnace till red ? Any advice would be appreciated thanks
Dave
where did you get the refractory cement? i cant find anywhere local here that carries it.
Menards was the only place i found it on the shelf
@@PaulsGarage ..Mann I had a stack of refractory brick off cuts, a 20L tub of special refractory cement and a 50mm tbick sheet of that white blanket. I was labourer and wetsaw for 3 bricklayers on a contract to build a 100metre long brick kiln. So was given some leftovers. One day ex gives it away to some pottery dude to relive clutter in the shed... 😐! I wish I could have that back ...the brick n stuff. She wasn't happy ...more than obvious now😆
Lol the wife buying new things that I take with my money is somthing that happens to me all the time
Like to see a video how do you prep the mould
Loved your humor! GO WIFE!!
What is the size of the crucible you used to melt copper? And the one you tempered in the video. Where did you get them and how much did they cost? How often do you temper a crucible? Thanks! I love your videos!
The one in this video is a #4 (6 kg), the copper one is smaller, i think it's 5kg size or less but it's from some other company. Both seem to work just fine, both got pretty vitrified though. I got both on Amazon (though 2 differnet supplies both selling on amazon), I don't remember how much the smaller one cost but the #4 was just under $40 I think.
Paul's Garage Amazon for 20$
Thank You for the video. Subscribed.
You're welcome! glad you like it!
Hay Paul, does that mean you don't want to play catch with some M-80's??? ;) 😜💥💥
I'd rather not become yet another member of my family to lose a finger, thank you very much
So how do you clean a crucible after you are finished melting with it ?
The expansion ratio of water to steam is 1 to 1600.
thanks for share mang..sangat membantu 🤩
What did you use for refractory cement in your furnace? Great video!
Hey bud good video. My only question would be do I need to do that with a small graphite crucible. Like the one you get from amazon small fits in hand. I’ve read to treat it with borax. If it’s graphite is that necessary
Personally I don't use borax anymore, just heat. Dont know if that's advisable in all cases, but I've never had an issue from non-borax treated crucibles
Does it make the kitchen/oven smell?
Instructions that came with my crucible said to use boric acid oe anhydrous borax I see that you did not, and your way looks more to my taste. how has your crucible worked since curing? thank you
It has worked perfectly. No issues whatsoever, and the clean surface inside is much easier to clean. That being said, I havent used it for anything hotter than copper which is well under the heat rating on these
What size is that crucible
Paul, What size is that crucible and where did you get it?
I think the one in this video is a #4 graphite clay crucible from PMC Supplies. It supposedly holds 6.5kg of brass i think, though i have only used it for aluminum (i have a different crucible for copper alloys). PMC has a website, but i got a better price buying the same one from PMC's Amazon store front. No idea why, it's the same crucible from the same place, but ordering it on amazon was cheaper. That may have changed, however.
Thanks for the info.
You do not need borax flux? If i am trying to cast a cooking skillet out of copper, will borax poison the food I cook in the skillet?
I followed the instructions from the manufacturer of the crucible, they do not recommend borax flux for tempering or even for casting.
Can you make crucibles out of drilled out firebricks?
no idea, i've never tried. seems like it might be dangerous, firebricks are pretty brittle.
Yes
there are folks like me, who when reaching into a bag of coal, stain themselfs, and even sometimes the clothing, and get their nose black from the dust too and look silly and all....
and then there are such lucky bastards like paul who clould wear a freaking white tuxedo and doing stuff like that....
i am jealous!
White tuxedo, theres an idea for a new work outfit!
nice job.
Where did you get your crucible from ?
+Darkcory Gaming PMC supplies, they have a website but also they sell through amazon
I'm in Australia so...
I noticed that your using charcoal, I used that stuff for a while until I found REAL coal, I forgot the name of the place where they sell it but the real coal get like 100 times hotter ( exaggeration but you get it, I hope... ) but I recommend real coal if your trying to melt something with a high melting point, but the down side of it, is that it produced A LOT of smoke when being burned and it will clump up into a big chunk, but you can break the chunk with some force. OH and the ( it think ) is MABYE bc it has like some time of oil in it bc it’s real. I think
Lump charcoal is far better than briquets, and I read in a blacksmithing book that charcoal was preferred by Smiths until they started running out of area trees.
Regardless, there are differ nt types of coal to, and anthracite coal is a good deal more energy dense than bituminous or sub-bituminous coal.
But then there's coke, which I would assume is most commonly available to regular folks, as it's what can be used for heating and is popular in smithing.
I don't know, coal is confusing
Subscribed for more outros
hi, i want to ask if i can melt different metals in same crucible like aluminum copper brass bronze and so on thank you
+tracychapman1000 preferably you want a different crucible for each metal, so as to prevent contamination. The same type of crucible should work for copper, brass, and aluminum, however.
sir you have done annealing process
Hey bro nice you moved on to that
I've been in a couple of explosions. Blowing up isn't that bad really.
Well if you have survived enough of them, i bet an explosion becomes just another Sunday afternoon
So how long should if take before it gets red hot? Roughly... Sorry if you answers this already!
+John Zmuda depends on furnace design. Maybe 20 minutes for me with lump charcoal.
When a solid turns red at about 960 degrees f it's called the draper point
I didn't know that, thanks for the info!
Hi, love your videos. What size (number) crucible do you have there?
Thanks! It's a #4 (6kg)
I tig welded a length of pipe to a plate and that's my crucible until i learn how to not break things. 😂
Would a heat gun dry out moisture?
What would happen if I you didn’t temper it?
Paul, when are you going to ditch charcoal and switch to propane?
One of these days i'll switch to propane. The thing is I have very limited time so i have trouble justifying an 'upgrade' to a thing that already works when there are more things I don't have at all that I want to make. There are some pretty nice designs out there, but something like a regulator i would have to buy, and they aren't cheap
I know molten meatal hurts I found out the hard way lead solder pops
That would huuuurt. I’ve been hit by sparks but never molten anything
No borax?
hello sir! that was a gear video i just have a question, isn't it harmful to put the crucible inside the oven? i mean can you bake or cook after using it to cure the crucible?
+Marcos Ruiz yes, but I only put a clean crucible in the oven. Just clay and graphite. If you melt anything in the crucible that could release fumes, you might not want that put back in the oven, but some people do anyway to bake out moisture. The crucible itself is just a bowl made of clay.
+Paul's Garage, thank you so much sir! good luck with all your future projects!
Did you coat the inside with borax?
I'm still going to melt cans in that crubile
get gud
I thought you were suppose to fill it up with borax?
sir how did you make that clay crucible
what ingridiants?
Pretty sure it was acquired from a merchant of such goods, the cost of an item such as this would be increased by possibly100_ 300% or more if it were pre tempered due to the amount of fuel and time involved and I'm only guessing may be something in temper it as you will use it crucibles like that.
Can i have link to that crucible?
My current crucible until my clay-graphite comes( free, long wait shipping) are soup cans... with propane I can melt about 25 cans in 3 minutes w/o risking a spill. Would not make my special aluminum soup again...
+Asher Mickey aluminum soul doesn't sound too appetizing
+Paul's Garage also aluminum soup. Stupid auto correct
It tastes A little hot..
i thought the extinguisher crucibles just rust because of the heating they go through.
The heat does cause scaling but the aluminum also dissolves it from the inside, even really thick steel crucibles are susceptible to that
Do you recommend a teenager with no metalworking experience tries this? Also, how often do you temper a crucible?
+Shyam Padmanabhan I temper it when I first get it, that's it. After that I sometimes drive moisture out by putting it in the oven for a while at 300f. If you aren't an adult I would not suggest doing this. It's very dangerous, and bad things can happen quickly.
As a preteenager I would blacksmith on my mom's kitchen tile using the stove to get closehangers red hot And hammer on them
Did you melt the graphite clay on the hair dryer side of the crucible???
It didn't quite melt, more like it vitrified. Clay contains a lot of small pieces of silica (SiO2, the stuff that makes glass) so when it gets hot enough the pieces melt together and it looks glassy. It was in no danger of 'melting', it just looks weirder now.
kaowool is better for heat resistance
So where do you buy a crucible ?
Amazon
Is there any way for me to get all the crap out of my crucible after I melt cans?
Not that I have found. I don’t melt cans in a clay crucible for that reason.
Paul's Garage My crucible has tons of crap in it now. It's awful to look at.
@@cryophile get it hot and try turning it upside and banging it out
Happy wife happy life 😊