Pressurized furnace, and other ruminations

Its a 60. I think it will be fine for aluminum but the bronze is starting to make me think about getting an alternate fuel source if it takes my furnace that long to melt. I was thinking more like 15 to 20 minutes melt time for bronze, but I have not used it yet so I was just making an uneducated guess.

 

That is what I am using...20 lb propane tank with roughly 2 inches of castable refractory on sides and blu ram in the bottom. I can get the #8 crucible glowing red in less than ten minutes(probably closer to five) with my lid on. I cant put my lid on unless I have the gas down to around 8 psi or it smothers it out. I tried using compressed air but honestly I think it gets hot faster without it...so far. I think my burner design is the issue. Its pretty much unrestricted airflow and when I use compressed air it just blows the gas out the top of the furnace. If I put my lid on with the gas too high I get flames coming back out of the gas inlet...back pressure I guess..too much air.

 

I was worried about the used motor oil smell/taste on the turkey, so I switched to propane for the fry. It turned out perfectly!
I wonder if waste vegetable oil would add even more flavor? That's something else I need to try.

 

Try connecting two propane tanks to a single burner, this helps prevent the typical freeze up by splitting the flow.

 

I'm using an inline filter to scrub the waste oil before sending it to my furnace, but it seems to clog after a few hours of use. I've considered using a disposable automotive oil filter, but not sure how to fit an existing filter mount or connect it inline.
What are the great ways you've come up with to filter dirty oil?

 

Thoughts:

1) mix dirty oil with a lower-viscosity solvent, e.g. diesel fuel, jet fuel, or similar. Failing this, apply warmth.

2) use a layered approach: a coarse prefilter, for just after the blending process, followed by a finer filter during transfer from storage to the furnace's tank, and then the truly fine filter on the outlet of the furnace's tank on the way to the burner proper. This last can - or, perhaps, should - be a disposable automotive-type filter. You'll want to do research on what kind of filter will best suit your needs - say, "which is the largest one AutoZone sells that fits your setup." There are remote filter adapters that make fitting such filters a straightforward matter.

2b) As an adjunct to getting foreign matter out of furnace fuel, take needed steps to prevent dust and dirt getting into the fuel. Open containers attract rubbish.

3) finally, document what you have, and where you got it. How much you'll need to do this depends on what you have for resources, how good your memory is - or is not - and what kind of outcome you want or need.

The above is what I plan to do when setting up forced air and liquid fuel at one of the furnaces where I've done foundry work.

 

When I ran used motor oil, I only used a tea strainer in my funnel to clean the crap out of it. Most of what I found was actually oil filter fuzz in my oil!
And yes, a piston airplane oil filter is the same crappy filters found on your car. They just cost 10x more! A stand pipe in your oil tank feeding your burner will go a long
way to keep you from plugging up! Look at 'H' in the photo below. Pull your oil, fuel or whatever from there. Never from the absolute bottom of your tank. That's where the trash collects.

Best motor oil to run in a furnace is turbine oil. It flows like water, is crystal clean and has ZERO combustion byproducts! FWIW, I usually only change turbine oil once every two years. And there is no recommendation from many engine manufactures to EVER change it! Yes, it can be a little tough to find, but not if you make friends with a jet guy. The stuff is 20bucks a quart!

 

Aircraft tend to be cleaner (for contamination) than autos - or do they? Secondly, I'm thinking about a situation where the oil in question has been gathering crud for a while. Even wih substantial dilution, it will need some serious cleaning to run through an ersatz quiky burner. Thirdly, some burners need especially clean fuel, e.g. Delavan/Hago.

Example: dilute "black goo" with roughly the same volume of "solvent". Transfer resulting liquid to yellow fuel jugs, using a filtered metal funnel, i.e. 60-100 mesh screen. From jugs to burner fuel tank, use 120 mesh paint strainer; in piping to burner, spin-on automotive filter.

 

Not a piston engine airplane. It's just as nasty and probably worse than cars because of the leaded fuel they still run. The only thing missing from the oil is the potential for water coolant because of air cooled. When I ran oil, in the winter months, I would add about 25% jet fuel just to keep it flowing. The Kwiky burner is pretty forgiving to slackers like me.

Jet engine oil comes out looking new even after a couple of years in service. It never gets near the combustion. The only thing it does is lube bearings. I will say the level of filtration is much finer than a shitty paper element. Most are fine screens around some kind of filtering media, so you don't end up with fuzz. Add to that, there are delta P indicator pins to alert of filter or bypassing issues.

 

Fine screens? 200+ mesh? (I do have a pattern for screen filters, and I had done it with the idea of using some way of telling when it needed cleaning.)

Short of locating an FBO that will permit my securing "sumped" fuel, the best solvent I can do for volume is diesel fuel, with a small portion added of used charcoal lighter/kerosene cleaning solvent.

Not sure if I have enough tankage to do a stand pipe. Might need to use a water absorption element. Again, I plan on using an "ersatz quiky burner" - ersatz as in "it doesn't use plumbing fittings for the bulk of its construction." (Lathe and mill are available here.)

 

Yeah, 200 is typical, the better ones are metal mesh and cleanable. My FBO is drowning in sump fuel so I can cart off as much as possible for free. Too bad I don't own a 1978 MB diesel sedan.
For fuel tanks, I use 30lb Refrigerant drums. They are pretty thin tanks, so brazing is the way to go for attaching fittings and a sight glass. With an unpressurized fuel tank, I never had to shut down to refuel. And I only need about 2-3ft of drop to gravity feed my siphon burner. All comes down to the burner and willingness to run an air compressor. Some here don't own compressors. I couldn't live without mine, the bigger the better!

Diesel would be good to go too. I used to preheat with jet-a and then switch to motor oil after about 10mins. I'm happy not screwing with the oil anymore. I might have to rethink that if I ever try iron. I wonder if there is anyone here that has melted iron and NOT used oil?

 

The eventual goal IS iron, yes. Aspirated propane takes 40+ minutes for aluminum. No, I did not build the furnace. I just need to get it to *Roar.*

 

With a pressurized tank one of my biggest priorities is keeping water out. There are a couple of sources: already present in your waste oil and brought in by compressed air. It may be less acute in dry areas but it is an issue nonetheless. Having a means to tap it off is important. Water may be helping to clog your filter, maybe not, but you sure don't want a pocket of water spraying into your furnace. Antifreeze and rainwater in the oil are the biggest culprits so when I get fuel from a questionable source I settle it out in kitty litter jugs a couple weeks before dumping it in the tank. If I get a layer of water in the bottom of the jug I just pierce it with a nail to drain it off and then put my finger over the hole when it goes black. It's not all over for the water though. If it's emulsified, which can happen in cases of blown head gasket,etc., simple settlement won't completely remove it, but with further filtration it should be ok unless you've got butterscotch pudding. Blown engine experts will know what I mean. At any rate, watch your sources. A polite no-thank-you can save a lot of mess later on. (One of the keys to a happy life.lol)
A standpipe or dip tube that doesn't touch bottom is a must as far as I'm concerned. Although I always tap water off first and then mix my oil to make it homogeneous before use (which will stir up crud anyway), it just seems intuitive.
Pre straining through a tee shirt during transfer works well to get major gunk out, but the heavy hitter is the spin on automotive filter. Some use a final small oil filter at the burner connection as well, but I have yet to try that. I don't know how well some of my heavier fuel mixes would flow, especially in January in Buffalo.
As you can see from the pictures I use a hot water tank. I could have used a smaller one but since I don't move it and it takes the same footprint as a smaller one I take advantage of the storage volume. Google gas hot water tank images and you'll see the anatomy. Pressure into the hot side, oil up the dip tube and out of the cold side. Pressure relief valve (!!!) and fill port goes through the former anode hole. Spin on filter mount came from a mechanic friend. The small pipe and air fitting on the right side of the right hand photo is where I attach my compressor line to blow air down the dip tube in order to stir up the fuel prior to use.

 

The water heater tank is a good idea. I see yours is gas... A small electric one plugged in and you'd never have flow issues in NY when its 20 below.

 

Actually, I can think of a possible means to heat matters up. If there is a screw fitting at OR near the bottom, one can screw a cartridge heater into it. Fit a one to two hundred watt one and plug it in a few hours prior to use.

Would a sediment bowl, e.. gascolator, work to catch water?

Seems there are such filters, chiefly for diesel fuel.

 

I'd end up on a State Farm commercial.

It has a through chimney which has potential. Safety concerns can be overcome but switching to mainly diesel in the winter solves the flow issue.

Pete

 

Can you get #1 diesel during the winter? Supposedly that's closer to kerosene.

 

I NEVER grow tired of this commercial.

 

I can see why! I hadn't seen that commercial before but it reminds of at least two episodes of Mythbusters where they blew up electric water heaters.