Alex W.

note: This is in in relation to furnaces(smithing and melting) that use a layer of kaowool in between the hotface and the outer wall. I hear a lot of good things about efficiency being increased a fair bit as a result of a highly reflective surface being added to a furnaces interior, as it inhibits the absorbtion of infrared and other radiation into the walls which would, as a result, emit on the other side, and also conduct to the other side, greater amounts of energy that is instead being directed at the item you are trying to heat up. However, I wonder what would happen if the exact opposite, aside from it's insulative properties, of ITC-100 was applied to wherever the intended hotface would be going prior to adding said hotface, so that instead of a highly emissive surface that reflects anything that is reflected back at it from the outside wall of the furnace, you get a highly absorptive surface that emits less than the hotface, which I figure is at least somewhat designed to have high emission and reflectivity as a hotface would typically be designed to do. I guess it would be better the focus was shifted to the reflectivity of the outer wall and whatever is between it and the hotface, because the castable refractory making the hotface is definitely a few steps down in reflectivity from ITC-100, but, it would be interesting to know how much improvement occurs as a result of a black coating on the outside of the hotface layer, which would be easier to apply if the hotface is firebrick like I have. I already tried this on my firebrick, and I quickly found out that the black pigment of the spray paint I used was either just carbon, or titanium oxide, which in one go was completely white again due to oxidation. I, unless I find a source of something that stays black, won't be trying it again if it exceeds $10, it's just not worth it in my case, but, I decided I would share this idea and see what everyone else thinks, cause it's actually kind of cool to think about. But anyway, thank you for reading this, I hope you have found this at least somewhat interesting, and have a good day.

Now, I didn't get any footage of it, and I could change that, but, I did a slag run, which I decided to do because I had a lot of aluminum come out with the slag I pulled out on a couple melts, which I retrieved about five or six muffin ingots of from about two liters of. I added borax to help separate the aluminum and the slag, seeing as that's what it's usually used for. But after I let it sit for a while to do it's thing if it even does at this point, chunks of slag started glowing hotter and hotter, behaving like pieces of magnesium, getting brighter and brighter, and started emitting smoke as the whole top of the slag layer was glowing nearly white hot. And that prompted me to immediately remove the crucible and start taking out the slag out of fear I might max out the crucible's temperature rating, not knowing if it would continue getting brighter to the point it hurts my crucible, and it slowly died down, both inside and out of the crucible, and it was very powdery with a lot of crumbly chunks. I was running the foundry, as I had found out later, very lean on fuel, so there was a lot of excess oxygen in the air mix, which seemed to help, I turned the fuel injection up and it seemed to dim a bit, so I think that may be a factor. I know that aluminum is used in explosives as a fine powder, and that it reacts with water when it is mixed with gallium which compromises the oxide layer it forms with contact with air, like when it's a liquid as with gallium or a melt. So, as a completely original guess I made up on my own, I'm wondering if somehow, as a result of the borax being added, and excessive temperatures, it was able to burn whatever aluminum was trapped in the slag at the time and give off a white glow, and, as I forgot to mention, what seemed to be a little bit of white flame. But, as is almost always the case, it isn't the truth, or even close, so, I am asking if anybody over here understands what's going on. But when it comes to this next effect which I observed, I am a little more confident I am correct with my guess as to what's going on, but regardless, I think it looks pretty cool. Pretty much every time I melt scrap that has paint on it, or something else that burns off(I can't remey if it does it otherwise hehe) there's this weird blue glow around the slag, especially when I pull out the crucible to pull out slag and pour it, and I'm thinking it is all the carbon in the slag that's left over from the burnt paint. Is this a correct estimation of what's going on, or is there another weird explanation for this propane stove flame colored glow? And, one more thing, does quenched slag usually smell like raw eggs? I think the yellow green paint on the majority of my scrap had sulfur in it, and I think it is a factor in the amount of blue glow around the slag in my scrap melts, it seemed a lot more profound, but that's probably because of the increase in size of my crucible, but I'm not quite sure. Anyway, thank you for reading this, I hope I haven't been a bore, and have a good day.(sorry I don't have any footage of this, I think I'll get some some time) Also, here is the slag I pulled out after melting it a second time:

I already consolidated about a couple years worth of aluminum scrap, it was extremely fast, I have a liter crucible, and a wicked hot foundry, but I haven't properly tested out the predicted version of the brownie pan ingot caster(the other one had a separate bottom that kept leaking, not flush, especially with the sand). I'll get back with details when I'm done with the test, which is pretty promising given the results of the last test. During last test, friend pulled out the divider prematurely and I got a pan of aluminum squares that were literally as soft as brownies, which was really funny to play around with, but the divider was free of anything sticking to it, which I hope is the case this time as well. I have a lot of information I could post on here, even after all the planning I still got things wrong, but not too badly, it's pretty cool. In fact, I have a very interesting experiment I still haven't posted about involving black spray paint. Edit:(update) I actually learned a lot of extremely useful information, I now know how bright 2300F is, I exceeded that and was too weak to let go of the magnificence of the near cast iron melting power of two inches of kaowool and an inch of firebrick with a good ratio of propane and air going into it. I melted the firebrick I accidentally ordered the wrong temp rating of, but only the bottoms of the ones the blower was aiming at, thankfully. I also know that it's very important not to drop ingots in a near full crucible, it was accidental, but I know I'll be a lot more careful and get better tongs for putting them in there, I had a big splash and lost good chunks of my firebrick floor to the frozen pool of aluminum. And, I also know, at least without rust in the way(the charred paint seemed good enough, but I was wrong, and impatient for that anyway), that my brownie pan thing isn't gonna work, at least with the divider already being in there, I could've waited until the melt became, funny enough, like a pan of brownies before I put it in. And, I was unpleasantly reminded to make sure your pan isn't aluminum, I had a pool on the brick I set the pan on, and I have a bunch of landscaping rocks in now. I am a lot wiser than I was going into the last melt, I sure as heck will not make those mistakes again, but I'm glad I found out why I shouldn't, it gets a better impression in my head for the future. Pic #1: Melted 2300F firebrick (I got them really cheap, so no big loss, fun testing it) Pic #2: the sad failure of an aluminum pans to contain the overheated aluminum, witha brownie divider stuck in it Pic#3: the aluminum that got all over the foundry after I dropped the aluminum muffin ingot.

I have used ingots a couple of times, and I understand exactly what you mean. I might even be able to add an entire crucible of aluminum or whatever to a single ingot if i get a shape that won't allow anything to melt and drip out of the crucible, probably a somewhat shrunken crucible interior to account for expansion. Smaller ingots would be a wise idea if I needed a smaller melt though. Btw, is there anything wrong with a little sand ina melt, or is it gonna sink or float and get caught in a bit of slag? I think that's why I didn't originally go with it in the first place.

Nevada.

I have a few totes of scrap I mean to put in a single tote, and I don't wanna fiddle around with a bunch of slag in the middle of a project, I'd rather use ingots.

All the home foundry enthusiasts online are extra careful over aiming their crucibles above about a bunch of muffin tins as a way to make ingots, and I believe a single pour is a lot safer. All that time extra carefully pouring aluminum or whatever into a dozen ingot molds opens a door to a mistake a lot wider than a single pour, a lot of injuries prevented.

I assume you are referring to kastolite 30, but I would like to be sure. But seriously, I really appreciate the input, it's a big help to me.

I may yet aquire a bag or two of kastolite, which I will need guidance on, but I would like a little information about the way satanite degrades, because I want to know if a solution exists, such as whatever I can think of or find to make satanite stick to the kaowool so it doesn't matter if it cracks, or anything I can add to prevent cracking in the first place if possible. As I posted above, I'll be operating around 2300F, and i think up to 3000F is in my reach.

I would be willing to put in a bit of time in order to produce it myself if I get a good recipe I can trust. I expect up to 2300F operating temps, and I can fire it up to 3000F if that's how it cures, which is the only time I'd ever exceed 2300F.

A good prediction I hope is inaccurate, at least for aluminum. As long as a barrier exists between both the ingot and it's mold, I believe it's a high probability I will be able to knock out the ingots. Also, doesn't aluminum experience shrinkage when it freezes?

I know a possibility exists, a very good one at that, but a method untested is a lost opportunity. I believe a paint layer is enough of a barrier, even after burning, and only expanding of the aluminum is in the way. Whether or not a layer of anything exists after a pour, or isn't able to remain during a pour remains to be seen.

All the home foundry enthusiasts online are extra careful over aiming their crucibles above their muffin tins as a way to make ingots, and I believe a single pour is a lot safer. All that time extra carefully pouring aluminum or whatever into a dozen ingot molds opens a door to a mistake a lot wider than a single pour, a lot of injuries prevented.

Idk if anything changes because of this, but I opted out for a couple ceramic fiber boards as a way to spread what I have found to be 10.7kg max for full crucible and whatever is added by the ceramic fiber board. I will be aiming for a 10" interior, but a 13" interior is a possibility. In other words, I'll have a 10 to 13" kaowool circle on which about 11.7 kg I hope will be spread over. I will be operating at about exactly what the kaowool is rated for ,2300F, but there will be a fairly insulative layer in between the hotface and the kaowool layer.

I admit I was a little stupid, I only ever searched kaowool rigidizer and silica powder, which only yielded a bunch of lotions, and I didn't dig any deeper.