Seasoning (tempering) Graphite Crucibles with Borax 

OK. That's great. However, if you want to melt metal in style (obviously more important than... pfft... "safety") be sure to wear cargo shorts and crocs. Definitely don't ruin the look by wearing safety glasses. Sunglasses are the sure way to go. Of course I'm being sarcastic, but I can just imagine some nitwit out there working with molten metals dressed like that or similarly. Saw one video where a guy was pouring molten copper into a muffin tin, wearing sweats and tennis shoes. Already a bad idea to use a muffin tin for copper, but I'm pretty sure he didn't preheat, either (at least he didn't show it). Because when he went to pour, a minor steam explosion happened. Some almost landed right on his foot had he not moved as quick as he did. Your safety concerns and suggestions are definitely good ones.

Assless chaps 😮

I'm getting close to being able to pull out the foundry and get back to it. Really looking forward to it. Glad you are enjoying as well.

Post more info about stuff like this. Thx.

I read that you're not supposed to put fluxon the crucible itself, that it would damage it. And to nevwr pinch and grab the crucible with tongs, you can crack and break it. Where would be a place that we could gwt safe information from? Because I feel like this guy's doing these things because he read them somewhere, and just thinks its proper?

@@dethmaul You don't temper or season your dinner plates or crockery so why the heck would people want to do this with crucibles is beyond me :)

@@dethmaul Real graphite crucibles don't need any seasoning. In fact, putting borax inside will destroy the purpose of a graphite crucible. Another commenter spoke about graphite ceramic crucibles for which seasoning is ok but seasoning a graphite crucible is absurd. To learn more about good casting practices please seek your local trade school. They might have night classes. Too many times YT videos are created by the blind pretending to lead the blind. It's not because online jewelry equipment sellers are willing to sell forever more tools that the art is easy. It's better to learn the science before trying to reinvent it. Otherwise, we remain limited by what we think we know but don't really know actually.

@@moonshiner2977 I don't think you heat your dinner plates at over 900°C to melt metals in them, do you? Ceramic crucibles need to be seasoned with borax otherwise they will contaminate metal melted in them. However, graphite crucibles don't need to be seasoned and should not be seasoned.

That will be due to the quick lime that comes from shells

I don't remember exactly. In general though I usually to not go real tight when tightening screws down. I'm about to fire up the furnace again soon so I will let you know if I notice a difference one way or another.

It won’t work with a torch, maybe oxyacetylene but not a propane torch. I tried and the borax just didn’t want to melt all the way.

I think it just helps prolong the life of the crucible. Some say you don't need to do it others say you do. I was told that it would extend the life of the crucible so I figure why not.

Rob Crawford Okay I just read this comment and I know it is 8 months old at the time of my posting. However, please do not start melting metal in a crucible that has not been heat treated first. If your crucible has moisture in it the crucible can crack and leak molten metal into your foundry or worse around you when you pick up the crucible for a pour. To heat treat a crucible place it in your oven at around 300F for a few hours 2-3. Then do a dry burn of the crucible in your foundry till it glows red hot. At that point let it sit in the foundry closed until it reaches room temperature. After that you can use the crucible. Store room temperature crucibles in dry locations so this process does not have to be repeated.

@@alphacentary and a year later I comment... I didn't know this when I got mine a week ago for aluminum. Ordered a new crucible to use exclusively for copper and am now heat treating but slowing rising temperature in my electric crucible. 400c x 15 min 600c x 15min 800c x 15min Etc... until I reach maximum operating temperature. Any qualms with how I'm heat treating mine?

@@Antassium You can just bake them in your oven for about 30-60 mins on high heat. Keep in mind I only use 4-8Kg clay graphite crucibles. This tempers the crucible and prevents steam cracking. Once it has cooled put it in your foundry and heat it till it glows red. Let it cool then inspect it for any large cracks. If you have any large cracks forming it’s defective. This is very rare though. If it is clear of major cracks it is good for metal melting. However, I do recommend you keep your crucible in a dry location after every use. You can store them in your foundry so long as it is in a dry location. Also when you do a melt always pre heat your tools (stir rods, graphite molds, tongs, etc) to prevent steam explosions.

Maher Alsayid most crucibles are made from a mixture of two. A pure graphite crucible shouldn't require tempering or flux besides using it for an anti stick component.

I think it's powder coated graphite. Mine did too.

Good questions. I'm not sure and I don't have it with me now. I know it's big enough so that when it was full of copper its was heavy. Hard for me to lift it out of the furnace with the small tongs I had.

Here is a quick link I found that explains Borax use with Metallurgy. www.etimineusa.com/en/applications-how-borates-are-used-metallurgy

the borax is used to aid in the melting. its used as a flux....

Borax is flux

@@MakerCK never trust manufacture and what there products do.....

Fahrenheit.

You want to cure it if you suspect moisture has gotten into the crucible. If kept in a dry place this shouldn't be an issue very often.

When I’m using mine in my electric I usually fire it up to maybe 200f for a little bit then turn it up for smelting

Why not? I plan to make a lot of aluminum bronze and your assertion intrigues me. I was under them impression borax would help me make better molds.

the foundry in itself is toxic asf

my thoughts too.

It will help the crucible to last longer. Otherwise it will end up crumbling after a while.

your crucible could explode if you don't purge it of potential moisture. definitely at least do the over and bring up to temp slowly. i think the borax also decreases the amount of metal that sticks to the crucible walls.

I just got my new Crucible and being a rookie I threw it right in full heat and it cracked within minutes

@@stevenrenaud4883 the crucible can be completely destroyed by the moisture, the borax is using for the monlten metal not hold in the crucible.

Do you use mule train borax?

It was recommended to me by the company that I bought the foundry from; they gave instructions with the kit I bought.

According to Morgan the company that makes the super salamander crucible, you are "NEVER" supposed to borax flux a clay graphite crucible

He has a furnace not a foundry. The place he does his work would be his foundry

He has a tong not a plier