Safe way to light oil burner?

Now, hold on now. Let’s not be too hasty with the important decisions here. More info is required, I think.

Are we talking about a truck load of street hookers, or a truck load of high end escorts? Also, how big is the truck?

 

I used my siphon as a pure siphon for quite a few melts too. It worked ok but was fiddly for the reasons Pete mentions. I found I needed to be able to put more fuel through it as it seemed Limited to a liter or so per hour. Once I put an automotive fuel pump on it, max fuel delivery increased several times over and the dependence on Compressed air pressure nearly vanished. Other things I should have earlier was put a good cheap inline fuel filter on the line just before fuel enters the nozzle. The orifices in the nozzle are fine and clog partially easily. But the fact there is a partial clog may not be obvious when the furnace is running. Something won’t seem quite right, but why? Finally, I probably am the only guy here with a Flow meter on my fuel supply. But for 20 or 30 bucks, it is a big plus. Now I can actually see what fuel flow is and I’ve learned the optimal flow rate for best furnace performance for my furnace. I can “measure” combustion air flow with marks on the blower shutter and can measure compressed air pressure of course. So, all the variables are known and I find it so much easier to nail the sweet spot right away. For iron, the burner needs to be tuned just right or you’ll have a slow melt and wonder why.

Denis

 

A few pissies of air on the tank could even things out I give you that. But if you don't build a 6foot tall fuel tank and don't try to run a furnace for 4 hrs straight, the fuel pressure from gravity actually changes very little. With my freon fuel tank, my fuel level changes all of 4inches during a melt. So the point is kinda moot. I refuel easily while running and avoid the risk of a pressurized vessel springing a leak just 10feet from the action. There was a guy on AA that had some kind of regulator failure and had a serious fire. SO ya to say I don't advocate a pressurized fuel tank for the average home gamer is an understatement. Do it only as a last resort and at your own peril. I really try not to carry anything hot OVER the top of my fuel line and compressed air source. Melt a hole in both of those at the same time and it's goodbye house! I use a harbor freight compressed air regulator for my 15psi, but if that thing takes a dump and goes full tilt, all it will do is blow out the flame. The venturi can only move so much liquid through a sized hole. I sucked at physics in college, but learned enough to get me this far. The real head scratcher is my gas forge burner. That one takes faith in what I believe is true and why I still have a neighborhood!

 

I know that it’s not strictly necessary, but I decided to go down the propane heat up for now. 5 mins with propane and I’m hot enough to go with diesel. Bam, switch over and no more worries. No flame outs. No wasted time. Just lots of heat. A few bucks in propane is worth it for me.

 

Good deal, 5minutes costs nothing. I bet after some practice, you'll learn what that thing likes to get it to light straight off diesel. 90% of the time, siphon guys are running too high of compressed air to get it to remain stable. Been there, done that. The compressed air is only there to move fuel. Your blower does the heavy lifting.

 

With pressurized fuel at 9 PSI and just opened up (.04-.08 L per minute to be exact)and atomizing air at 10 PSI and combustion air just gently blowing it will start the first time and every time with no blowouts. Once lit, just open up the fuel a bit and then some more combustion air. Close her up and let it rip. For my furnace that is .18L/min and 10-12 PSI atomizing air and enough combustion air to just allow a few inches of flame out the chimney. Too little atomizing air and and coking will occur as the fuel is not finely atomized enough and burn incompletely. Too much combustion air and the furnace will be cold. It will sound impressive but not be heating optimally.



The propane start sounds like it working well for you. And if you are satisfied with that, you are good to go. But, it should not be necessary.

Denis

 

I light my furnace in the same way. with about the same settings as you.

 

I see you're using propane. I hope lighting with the lid open. Your statement above to bleed propane into a furnace and then light at the vent hole will work until you get a stoichiometric mixture in the furnace and the lid opens automatically.

 

Knowing Jason, it would be an S-10 loaded down with 400 pounders. That would be three.

 

I personally think if you can atomize Diesel with some kind of hotspot or ignition source you can maintain the flame.

Jason might have hit the sweet spot with the end of his burner holding 2-500°C.

My homemade jobby burner is a mixture of a drip and syphon. It's not a mist, it's not a drip, it's a spit, And it lights. My drip hole is the 3/16". I have never tried an open air burn like Jason has demonstrated. But I'm willing to try.

 

I never tried propane, but I had ONE flashback on jet-a during testing that raised my lid a quarter of an inch. I might have even peed a little!
It doesn't take much to dork this stuff up and end up with an "automatic lid"

Some thoughts, A furnace MUST be able to run smoothly with the lid open. You will want to keep it running while melting. Remember when the lid is open, you have an oxygen rich environment. When the lid is closed, things change (goes rich) and without additional air, it will flame out. Notice in my video I start it, stuff the burner, bring in the blower, slowly close the lid and switch to full open on the fuel. My blower is on low during this entire time. The furnace is very rich and pretty sooty too. Lastly, I switch to high on the blower and fine tune the fuel looking at what is coming out the exhaust. This is why I like hard settings on blower speed. If you have endless options, you could spend the afternoon adjusting the blower and fuel trying to find the right setup. I needed repeatability and reliability.

During the melt, I can easily open and close the lid without having to futz with the burner or blower at all. It obviously will run a little lean during this time, but the furnace is hot enough to maintain the fire.

 

With my tiny little propane furnace (before building my current), I’d almost always light with lid closed via vent hole. Never a problem. Small size is likely the reason this worked. Not enough space for a fuel-air explosion.

Current furnace is much bigger. I’ve found that it’s too dangerous to light up this beast with lid closed. It can hold much more propane with enough air for a big boom. Now, I always light up with open lid. Additionally, I need to be much more aware of potential flame out situations. I wouldn’t want current furnace to reignite on its own.

 

Remember Jason is burning kerosene. It's between diesel and gasoline in flammability.

Diesel has a flash point of 143F, Kerosene 100F, and Gasoline -40F. If you've ever started a brush pile with diesel you know it's hard to light with a match. Kerosene is very easy. Diesel does not work well in kerosene lamps.

Jason is fortunate he has a ready source of kerosene. While it does not have as much energy content as diesel it does have more than gasoline. In my drip furnace, pressure fed, I can tell the difference in heat produced by a gasoline rich charge, I get more energy out of diesel, and more yet out of used motor oil. Used motor oil is my favorite fuel because of the high energy content.

 

Question about motor oil.

I use a weed whacker fuel filter to filter diesel. Seems like even clean motor oil would clog it up. What type of filter can one use for oil? Assuming using clean oil.

I do not see a straightforward way of putting a car oil filter in-line.

 

I use a spin on filter. The housing had been laying around the shop for many years. Originally I bought it for building a log splitter. Inline spin on housings are readily available. I dump all kinds of old crap into my tank from gear grease to ATF to lumpy stuff out of old engines. I've changed the filter once in a couple hundred gallons of fuel.

 

Maybe something like this, Bentation.

 

Yup.
Got a friend at a service station or junkyard?

 

This is from summitracing.com but any place that sells parts to your local racers will have one of these remote oil filter mounts

Expect to pay $20-30, they accept a commonly available automotive spin on filter.

 

Tea strainer is all I ever used. I had one of these, broke it in half and set it in the bottom of my funnel. You only need to get the chunky shit out of the oil. Passing it through a conventional filter is overkill guys. You are burning the stuff, not lubricating bearings with it. I mostly had filter fuzz in my oil. All airplane piston and automobile used oil.

3bucks from wallyworld.


More important is when you suck it from your oil tank for your burner, suck it through a stand pipe. This will solve 90% of any problems.

 

I have been using my Hago siphon for a few years now. I have only burned “clean” diesel in it. All issues with partial plugging of the nozzle disappeared when I placed an in-line 5 dollar fuel filter on the supply line. Be sure to place the filter in a part of the line that is never broken between the filter and the nozzle.



Tuning your burner for different fuels will add an extra challenge to the general operation of the furnace. Having some means of determining flow rate would make the process easier and more reproducible. Before long you would get a range for flow on motor oil vs diesel.

I wonder how well motor oil will perform given its greater viscosity and about 500 deg F flash point.

Denis