I was BS'ing with OCD recently about crucibles. And he brought up an interesting point I missed. Everyone is aware of the importance of conducting a proper heat cycle with a brand new crucible. Somewhere he uncovered a flux treatment as part of that procedure! I believe it was from Morgan too! We all know flux tears down crucibles, but I seem to remember reading this somewhere too and just dismissed it. Of course I can't find it now on Morgans site. What got me thinking about this was seeing Roberts crucible in his bike thread. I see some crucibles with a nice even crust on them and then I see this. It appears some of the metal has removed some of his crucible material. The question is where does that go? Does that initial flux prevent this? Why do some crucibles I see have nice even coating on them? Obviously, the end goal is maximum service life, no failures and no mystery material ending up in stuff we pour. Here is a helpful page from Morgan, but it's not on it. http://www.morganmms.com/media/1765/maximising-crucible-service-life-mgam.pdf For comparison....Look at this crucible, notice the even coating?
apples and oranges... Top crucible looks like a clay crucible with a graphite coating on the outside where the bottom crucible looks like it is silicon carbide.... . http://www.unitedpmr.com/graphite_breakdown_fluxing_crucible.php
Good Question! The very first Morgan A6 Salamander crucible I bought came with instruction to flux coat the interior. The A 10 I have of same did not come with those instructions. I just sent a written request to MAM and tried calling their sister location in George as well, left message and awaiting call back.
Cool. You probably dont have the paperwork that came with the first one do ya? Now we can get some clarification on this one. thanks John
Wish I did Jason because I got word back from M&M and they said that, Absolutely DO NOT flux a clay graphite crucible!!! PMC Supplies and I are going to be having a conversation come Monday morning. They now owe me a A6 Salamander crucible.
Probably the instructions these selling companies are sticking in the box with some of the crucibles. Who did you buy that A6 from? My A10 didn't come with any instructions.
My little A6 came off fleabay. It didnt come with any instructions. I know I saw this online someplace. Here's the link from ebay on the one I bought. http://www.ebay.com/itm/Salamander-...861623&hash=item2eb49a15bb:g:yTcAAOSw~gRV23YT It's been a good one for me so far.
I ordered my A6 through Amazon but it was sold & shipped from PMC. Community censuses here............ Other than a short life span (assuming), what happens when the interior walls of a Salamander Clay Graphite crucible is coated with Borax Flux?
Melt some metal and lets find out.... I bet nothing. But I haven't used flux yet in my bronze. Heck, I'm still trying to dial in the temperature.
this is a matter of misinformation directed towards a different goal, Legends expects most people to be doing analysis or refining, where flux is really required, if you are melting and casting known metal, unless you need flux... you DONT need flux... flux is not for the crucible, it is for the material being melted/ heated ... Break out the Navy foundry manual and see what it said about care of crucibles and the use of flux... I can tell you the Later ML RTMs directed not using flux in any nonferrous, because of induction furnaces, and the direction to only use new ingot and known scrap. V/r HT1
I have to agree with HT1, there is a lot of misinformation about crucible types, metal suitability, temperature ratings, etc. I have researched some of the Morgan crucibles. Below are first-use tempering instructions for a Morgan Salamander-Super. As I understand it, the tempering sets the coating on the exterior of the crucible, making it durable, and also drives out any moisture that may be in the crucible. Here is some info I have gathered over the years regarding Morgan crucibles: Note that the clay-graphite Salamander Super is "ferrous-metal-rated", and the silicon-carbide Excel and Himelt are designed for non-ferrous metals with lower casting temperature ranges. If you plan on doing iron work, I would recommend a Salamander-Super. If you are only going to do non-ferrous work, a silicon-carbide crucible may last longer, depending on the quality of the crucible. A poorly made crucible will fail with whatever metal you use; I have seen some supposed "iron-rated; 'its what the salesman told me' " crucibles fold up like a wet waffle as they approach the melt temperature of iron; thus the reason I stick with the Morgan Salamander-Supers. There are other quality brands beside Morgan, but these are the ones I have used and am familiar with. A Morgan "SALAMANDER SUPER" is a graphite crucible. It can be used with both ferrous metals such as gray iron, as well as non-ferrous alloys such as aluminum, brass, and bronze. Typical metal casting temperatures are 1562 F - 2912 F (850 C - 1600 C). Color is black. The PREHEATING / FIRST USE instructions for fuel-fired furnaces is as follows (per Morgan): A new crucible shold be preheated empty in order to minimize the termperature gradient across the crucible wall. If there is a risk of the crucible having absorbed some moisture, then the furnace should be initially heated slowly up to approximately 392 F (200 C) and held at this temperature until all moisture has been driven off. A new crucible should initially be heated slowly and evenly to 1112 F (600 C) on low power, avoiding local impingement of flame on the curcible. Subsequently the full heat input rate should be utilized to achieve a uniform bright red condition over the whole crucible at approximately 1650 F (900 C) at which point the crucible should be charged immediately, taking care not to packing metal tightly or bridging ingots across the crucible. Morgan "EXCEL" and "HIMELT" crucibles are made from silicon carbide, and are designed for use with non-ferrous metals (not iron). Typical metal casting temperatures for these crucibles are: EXCEL: 1562 F - 2880 F (850 C - 1250 C) HIMELT: 1830 F - 2550 F (1000 C - 1400 C) The color is red. The PREHEATING / FIRST USE instructions for fuel-fired furnaces is as follows (per Morgan): A new crucible shold be preheated empty until they reach a uniform bright red color (approximately 1650 F (900 C) in order to pre-condition the glaze. The preheating time will depend o the size of the crucible (can be up to one hour for a large crucible). Avoid direct flame impingement on the crucible surface. Below are photos of Morgan Salamander-Super (on left) and Morgan Salamander Hi-Melt. Very confusing nomenclature since you would thing they are rated for the same temperatures and metal types since they both are labeled "Salamander" (they are not). The black one (clay-graphite) is ferrous-metal rated, the red one (silicon-carbide) is not ferrous-metal rated. The red one (Hi-Melt) is Morgan's best and longest lasting crucible for non-ferrous metals. The black one (Salamander-Super) will work with iron, and will also work with non-ferrous metals. The red one (Hi-Melt) is not rated for iron work. They both have glazing on them that needs to be tempered prior to use. I have standardized on the Salamander-Super for all crucible sizes and metal types, and it seems to work well if tempered correctly and not abused, jammed, overloaded, over-fluxed, etc.
Excellent stuff. I "cured" my graphite crucible in the kiln. Nice and controllable heat. I need to buy a #10 soon, so I might go the silicon carbide route if I don't need a 2nd mortgage. lol Thanks Pat.
I really like to throw my crucibles in the oven at 300 for as many hours as the wife will let me to burn out any moisture , before they go into the furnace for the first time... I dont know anyway to make a furnace heat to 392, so that is sort of out, I suppose placing a new crucible in a barrel with a wood fire might get you closer then anything V/r HT1
Hang a heating bulb in your furnace over night. That crucible & furnace will be good & toasty come morning time. It's doesn't get hot enough to pre treat a new crucible but does a good job of getting rid of any moisture. I only got away with stuffing a crucible in the wife's over once........................
Graphite crucibles do emit an strong odor when new. And in my kiln, that first go around had a hint of cat piss. lol The pottery kiln is without a doubt the best way to accurately heat these suckers in a controllable manner.
I am Boycotting PMC Supplies. Will NEVER buy anything what so ever from that company again, don't care how cheap they list it. Called Monday and spoke to some manager about the BAD fluxing instructions that was stuffed into the box with my Salamander A6 crucible. I even informed him that I had contacted MAM about the subject and the guy tries telling me they were wrong and it doesn't hurt the crucibles. Then he tells me he will call MAM to get verification on the subject................ Wait a minute....... He just tried telling me M&M didn't know what they were talking about, PMC does everything under the sun to side step the issue instead of just replacing the crucible, then he tells me he is going to call them to get verification on the subject??? And get back to me which never happens. What a crappy company!!! Rant over.
