look what arrived this morning an MF30 and a DA40. Very pleased they arrived well boxed and not a mark on them not sure what brand the Mf30 is, I guess Chinese but the DS40 is a Mars Tiegel I bought them from Mathews Industrial products in Western Australia, and I must give them a plug, they were great to do business with.
Fire real slow over a period of a few hours up to red hot. I do it in an electric kiln then allow to cool very slowly overnight. And whatever the instructions say, DO NOT FLUX THEM!
Thanks Jason. That is exactly what I wanted to here. I have done the fluxing thing and I swear it makes things harder. I will use electric. I think it was something like 292°f for an hour or two then up to 1600°f or should I take it up to the intended melting temps???? 2000-2100°f I saw the back and forth on hear about fluxing and I think it may depends on what a person is melting and or making or what makes them comfortable... edit: I should say pouring temps 2000-2100°
Mars say to bring new graphite crucibles empty up to red heat slowly then quickly to bright red before use. There appears to be so many thoughts generally about crucible per use treatment its hard to know what to believe.
Flux at any stage of the game shortens crucible life. I have yet to use it once, but I only cast bronze and occasionally aluminum. Vincent is right, just like a-holes and opinions, there are a million of them out there. Low and slow and you can never go wrong. It's going to get plenty of abuse on it's first real fire when you charge it, light the furnace and heat up super fast. Can't go slow at that point. lol
All we're trying to do is get any absorbed moisture out of them. Most of us are aware of that but there seems to be an idea that the end user has to perform the final operation in its manufacture when all we have to do is use the product correctly. The same preheat has to be performed when a crucible has been unused for awhile: heat slowly, empty, up to red heat, then have at it. If your particular operation requires flux then use it accordingly. These things are ready to go out of the box. I do the same for the sake of my refractory while preheating my cold furnace, so it's pretty seemless. Pete
There was an old thread discussing fluxing of crucibles way back, may have been here or on AA. I'll try to find it but it was on the manufacturers instruction sticker and the supplier was questionable if I recall correctly. Personally I wouldn't do it and really can't see any benefit. Pre-heat cycle as others have said.
The people who recommend fluxing new pots are probably used to melting dishes, which generally do wish a load of borax for the first use. They're also likely to be accustomed to the use of machined graphite crucibles - which are known for having distressingly short lives when used for normal jewelry metals/alloys. "Three runs Max..." Here's a melting dish: https://www.google.com/url?sa=t&sou...FjAAegQIAhAC&usg=AOvVaw3Wv0BUH58pXOheT5wqGM5q With rare (?) exceptions, they probably do not use regular foundry crucibles, and hence think to do normal jewelry methods - including "use the pot twice and then toss it." That's the (semi)-rational interpretation. The deeply cynical "amateur sociologist" part of me says they do that deliberately as a matter of predation.
I agree, this way they get to sell you another next week. "Trust no one" has kept me alive in the Aviation world now for almost 3 decades.
The one's dennis mentions are for torch melting. and yes he is correct they do get a sprinkle of borax. Get it red hot with a torch and sprinkle very small amounts until lightly glazed. These are for silver and gold mainly. Aluminum - will destroy it immediately copper/bronze - in small amounts under 100 grams maybe half dozen times....maybe Silver - over a dozen times and counting...
Borax eats crucibles. I toss a pinch into the center of a melt when I am melting copper wire in an already melted pool of Everdur, and I keep it away from the sides of the crucible. I use beer bottle glass on every bronze melt. It keeps out the oxygen and when I scoop it off, most of the trash comes with it. Richard
Generic beer-bottle glass, i.e. color does not matter, or..? (Planning, eventually, to attempt cuprous alloys.)
I don't think it matters. It goes gooey and just protects the melt. Richard is in Mexico and alloys his own bronze. We can buy sil-bronze cheap here in the states between 4-6bucks a pound. Personally, I pay the man! I make enough crap around my address not to risk a screwed up pour because I forgot to add something to the mix. My scrap copper usually goes to the junk man. (Kinda wish I hadn't dumped all of it! I need a set of copper jaws for a vise)
I suspected it might not, but was not sure. There might be certain types which work "better" than others. Still want to get some silicon bronze, though. Just needs money, sigh.
1989 Bordeux or tequila bottles, depending how well you want the pour to go after you've emptied them I struggled a little with glass on my brass melts, sticky gooey mess, but I may have been borderline on temps looking back. (I sure as hell didn't know what I was doing)
Presuming your pancreas does not object, of course... Mine would, even if I most likely had my pancreatitis start in childhood.
Since we're talking about crucible tempering I figured I would ask a question. Pre-warning, I'm a complete noob to this and just getting ready for my first melt and cast. I got a #6 crucible with the furnace I picked up off Amazon. In great shape, was that silvery-gray color and as expected graphite rubbed off it onto my hands. The usual apparently. I tempered it using what I had seen in multiple videos, take it up to 425 in the oven for an hour, let it air cool, then put it in the furnace and bring it up to glowing red, then glowing orange for a while, then let it air cool again. THe question I had was what it should look like when it's done. Most of the pics I've seen they still resemble the original crucible in color and sometimes just get some texture to them. In my case it now looks more like pottery or concrete (the silvery-gray is not visible on the surface anymore). Is that normal? If I scratch it with a fingernail it's still graphite colored under the surface.
That's about normal for a Chinese made budget crucible, there's no embedded glaze to prevent the graphite from physically burning and the recycled crushed pottery (grog) they mix in will cause progressive crazing of the crucible. Name brand crucibles have an obvious lumpy shiny glaze on the surface that helps protect it. I had a crucible similar to yours and killed it after about 11 runs while trying to reach iron temps, I'll see if I can find the pics.
