Saving Private Brian

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  1. My question was not on the use of oil as a fuel, only on advice for commercial refractories. I chose to defend my use of oil after it became the subject of discussion, not bring it to your attention in the first place. Propane is simply not feasible for some of us -- it costs too much in my area and many other areas around the world to make it ever hopeful of being economical. A well-engineered oil burner could last a while, and not cost in maintenance the same as both purchase of propane and disposal of waste oil combined. Oil seems to be an area of intense pessimism on this site. Have you all had bad experiences with it or something?
  2. Oil is a better fuel than any of you make out. It has a higher energy density to propane and a similar burn temperature, and not all oils diffuse carcinogens upon combustion as everyone seems to make out. What about vegetable oil? We COOK with it. It's hardly harmful; to the refractory or to me; and a good oil burner will be relatively smokeless (the oils should, under high enough temperature, completely decompose under the heat -- pyrolysis for you there). Oil's greatest trait however remains to be its abundance. It is free. This means I can make my foundry the cheapest, most inefficient pile of junk possible, and it will still be economical. I will save far more money than any of you who are using propane, and I am capable of melting larger volumes of the same metals as you. You complain about the toxicity of certain oils I plan not to use, but I am also safer than propane-users in other aspects; such as how I share no risk of exploding if I'm careless with the tank, etc. In fact, advising newbies to use propane is probably as dangerous as it gets. And the final alternative - charcoal/coke - emits even more dust. Lastly, burning waste oil is far less damaging to the environment. Sure, in your immediate area it might smell a little, but at least I'm not using coal or gas, which, btw, will only continue to increase in price until one day they become redundant. Oil burners are also brilliant because they can burn pretty much anything that comes as a fluid, given you have a decent air compressor, although I wouldn't advise this. You're not changing my mind. Oil is a far superior fuel. Your complaints about harmful smoke are simply from burning specifically nasty oils in an incorrect fashion. Brian.
  3. I've hit a dilemma considering the volume of commercial castables available online. I'm attempting to construct an oil-burning foundry. I have an abundance of waste oil to use. I am to produce a foundry *capable* of cast iron, not that I will even attempt to try such things until then. I will mostly use it for copper, but since I'm making it now, I'd like for it to be able to deal with up to 1600C in the future. I hope for this to last a long time. I also hope to operate on limited budget (nothing over 100). I will be using a 20-gal steel drum I picked up. Fireclay or castable? I'm aware fireclay shrinks, so I'm edging towards castable. But then there's the problem of dense or insulating? I think a 1-inch dense hotface (increased durability and resistance to fluxes), and the rest insulating, but I'm unsure whether these two mixes will stick together and not separate after firing, etc. Would the dense hotface reduce the possible 1600C to enough to make it safe to use a 1200C - rated backing-layer? I could use perlite or ceramic fibre to provide additional insulation. I'm more on the side of perlite, mainly since it's so available, but also because it won't harm the structure of the refractory. Does anyone have any experience with any of these products, and can shine some light on which I should aim my focus on, especially considering my design does not need to be economical (my fuel is free after all) but does need to be strong to last a long time under the fluxes from the oil? Is dense refractory really necessary, or is the insulation I have planned out overkill? Thanks for your help. Brian.
  4. First post, here I go. I'm attempting to create a high-temperature (<1600C) furnace for melting mild steel. I plan to achieve the necessary from a forced waste oil/diesel burner, driven by an air compressor (propane is expensive in the UK, at least in my area). I've read a lot about refractories recently. I'm aware commercial refractories are far superior to anything I could plan to make myself, but I propose the question: can I actually melt cast iron/mild steel using materials I can obtain for more or less free? I have certain plans already: the foundry will be housed in a 20-gal drum, with a 1.5-inch 'hotface' and a 2-inch insulation layer. The general problem seems to be that materials resistant to high temperatures tend not to be very insulating, so I've devised layers to specialise to both purposes. The hotface will act more like a crucible than insulation, and will protect the insulation layer. Portland cement cannot be used here as it will kind of explode. Silica (play/fine) sand won't hold up very well either, which seems to melt at exactly 1600C -- my planned max. temp. I therefore need to rely on clay and grog to resist the 1600C heat, mixed with polystyrene beads which will burn-off and create air pockets which will allow the clay room to expand when heated. Grog will also help reduce expansion/shrinking of the clay, and therefore reduce cracking over time. I can obtain grog from old porcelain (completely white the way through) tiles for free, and the soil in my area is very high in clay (found barely a foot down), and is a yellow-grey colour. I'm aware due to the yellow it is slightly contaminated with FeO or some other contaminant, which may act as fluxes and reduce its melting point. Will this clay still work as a fireclay, or if not, is there a way to purify it? Another alternative binder is hardwood ash, so I've heard, but I lack any understanding of exactly how it behaves under super-high temperatures. I know it forms a sort of concrete, and could provide an additional dimension of physical strength when used with clay (increases the cold crushing force of the refractory, pretty insulating - more than clay I think, reduces expansion/shrinking of the clay). I really want to add ash to the hotface mix, mostly due to its availability, but I'm just concerned that it might melt (I'm also sure purity matters, and have no understanding of what type of ash I actually need). The insulation layer will be (I'm hoping) below 1200C, at which temperature perlite can be used. I can also rely on silica sand, which I will obtain from the ground here. In the South of the UK, we have lots of 'flint' or chert, which can be ground down (with effort) to an almost pure quartz-silica structure, once the CaO and CaO3 have been dissolved-off. That's another question - can I use CaO in the hotface? I recognise it's high melting point, but why is it never used? Has anyone ever had any experience with chert or flint as a refractory sand? I doubt so but I'd like to check before I try it. Silica (chert) sand will also form a stronger ceramic bond with the clay when fired than perlite, so less clay is needed in the insulating layer (reducing expansion/shrinking -- cracking). I can also employ fibreglass (just the glass) near the edges of the insulation layer to act as a binder (which used to be done with asbestos fibres, before it became semi-illegal over here). The layers might be reinforced with steel mesh (think: chicken-wire) around the outside, but not sure how useful that would turn out. I've heard varying suggestions on the amount of clay I should be using, anything from 5% to 25%. That actually seems like quite a big difference. I understand too much clay can introduce a multitude of problems, so is there a recommended amount, especially considering the home-sourced (yet incredibly sticky, and semi-grey/yellow purity) clay I hope to use. I hope this post will be of use to newbies also attempting homemade refractory, as I've just dumped most of the knowledge I currently have after hours of research into one post. I hope this project will also help prove something quite important - that completely homemade refractories are possible, and than anyone can melt and pour iron/steel on a budget of pretty much nothing. - Brian.