I am looking for a spark generator design that's simple, if possible, and produces a hot arc. Spark size isn't important so long as it's at least 1/8inch to at most 1/2inch. This is to be used to ignite a fuel/waste oil forge without preheating. I don't have access to a coil pack from an automobile and I'd like to build it from scratch anyways. Preferably powered from low to medium voltage DC or standard 110v AC. DC preferred. I've found plenty of things online but most generate sparks intermittently or are "cold".

"I lost the battle so I changed the war"..

 

Are you spraying the oil? It's the vapor, oil and air atomized together that ignites in an oil furnace. And unless you use AC it will be an intermittent spark, even from a coil pack as you call it.

 

Are you spraying the oil? It's the vapor, oil and air atomized together that ignites in an oil furnace. And unless you use AC it will be an intermittent spark, even from a coil pack as you call it.

Yes it will be sprayed with two jets colliding to assist with atomizing the oil. I do plan to have a start assist with gasoline injection thus the spark generator. A consistent spark to prevent vapor buildup until the heat self sustain's the oil burn. I have no issues using AC. I suppose it's best since I'll be using an AC blower anyways.

 

How about a conventional oil burner ignition transformer. Or perhaps you can pick up a cheap used neon sign transformer. Either of these would produce a spark with enough intensity, particularly if you are using gasoline augmentation.

 

Search Google for "gas grill igniter". They are dirt cheap and come in both electronic and piezoelectric versions.

 

I have many transformers, though voltages that high are overkill and cumbersome. I was thinking similar to the arc ignition in a torpedo heater or stove top. Sadly piezo igniter would be exhaustive since I'll be igniting liquid fuel that'll likely be saturating the spark gap with oils. Just a simple circuit that would produce a continuous arc till ignition is what I'm after. I've seen many circuits but the sparks are either small or way to large and powerful to be safe. Especially since it'll mostly be metal.

 

Would something like this be of any value?

https://www.banggood.com/DIY-Invert...-p-1224579.html?rmmds=search&cur_warehouse=CN

 

I was able to pick up a functional oil burner transformer from the technician that came to my house to perform maintenance on my oil burner. There was nothing wrong with the transformer. The calendar had dictated it’s replacement. I used it in a haunted house.

 

Would something like this be of any value?

https://www.banggood.com/DIY-Invert...-p-1224579.html?rmmds=search&cur_warehouse=CN

Actually yes. That's what I want. But not purchase. I can easily afford that but any maker knows doing it yourself gives more satisfaction. Awesome link, sadly no schematic. I've been dabbling in smithing for years but I wanted to do it as a weekend job and need my final set up to be totally t1t$ if you get my drift. I'm looking for a consistent, simple, easy ignition rig and a spark gap circuit is it.

 

Actually yes. That's what I want. But not purchase. I can easily afford that but any maker knows doing it yourself gives more satisfaction. Awesome link, sadly no schematic. I've been dabbling in smithing for years but I wanted to do it as a weekend job and need my final set up to be totally t1t$ if you get my drift. I'm looking for a consistent, simple, easy ignition rig and a spark gap circuit is it.

I know nothing of such circuits, but it looks like it would be easy enough to make a schematic from the diagram that they show.

from:https://www.banggood.com/DIY-Invert...-p-1224579.html?rmmds=search&cur_warehouse=CN



For my own education:

What is so "special" about the NPN [N50 347 Y]?

What do they mean about insulating the transformer for long life....
"For reliable long term continuous work, it is recommended to use insulating wax or epoxy resin to completely seal the transformer. If it is not sealed, the transformer will work under no-load in air for insufficient breakdown strength of the coil. Work prohibited no-load!" I don't understand that at all.

What do you mean by hot arc (vs cold arc?)

 

If your into smithing why not do it the way we did back in high school shop class, back in 1963? Light a piec of pare on fire in the forge and turn on the oil, though we had a gas forge. That was the same way it was done in the melt furnace for doing aluminum casting.

 

I know nothing of such circuits, but it looks like it would be easy enough to make a schematic from the diagram that they show.

from:https://www.banggood.com/DIY-Invert...-p-1224579.html?rmmds=search&cur_warehouse=CN

View attachment 176863

For my own education:

What is so "special" about the NPN [N50 347 Y]?

What do they mean about insulating the transformer for long life....
"For reliable long term continuous work, it is recommended to use insulating wax or epoxy resin to completely seal the transformer. If it is not sealed, the transformer will work under no-load in air for insufficient breakdown strength of the coil. Work prohibited no-load!" I don't understand that at all.

What do you mean by hot arc (vs cold arc?)

That schematic would work. I didn't notice it last time. Think of a hot arc as a welding arc and cold one as a cigarette lighter piezo. Since it's to ignite oil the arc has to be essentially plasma. Also I think that refers to eddy current's induced in the transformer and generating heat and degrading the windings. I'm not sure but as a guess the epoxy keeps it all still so it doesn't affect itself and possibly not to excite air molecules that would generate heat. All just a guess..

 

If your into smithing why not do it the way we did back in high school shop class, back in 1963? Light a piec of pare on fire in the forge and turn on the oil, though we had a gas forge. That was the same way it was done in the melt furnace for doing aluminum casting.

I did think of that but I was wanting to cut out the middle man(preheat fuels) to simplify the burner and minimize fuel intakes to just one for oil. Also it's going to be for blade forging so with open ports I'd assume the blow out of the ash would be horrible. Also I'd worry about slag when the oil contacted the ash and carbon. Though I suppose I'd just have to clean it once and a while is fine to

 

Looks like whoever is making these kits is using a transformer originally designed for something else and just adding an over winding. The original transformer is probably not rated for anything near 10KV and is operating on the verge of breakdown. Vacuum impregnating it with lacquer or wax might increase the breakdown voltage (I'm not going to look up the relative dielectric strengths at this time).

In any case, I would not expect that transformer to survive continuous duty for very long.

 

Looks like whoever is making these kits is using a transformer originally designed for something else and just adding an over winding. The original transformer is probably not rated for anything near 10KV and is operating on the verge of breakdown. Vacuum impregnating it with lacquer or wax might increase the breakdown voltage (I'm not going to look up the relative dielectric strengths at this time).

In any case, I would not expect that transformer to survive continuous duty for very long.

Continuous use isn't going to occur. At most 30 seconds but realistically around 10. Once ignition occurs it will quickly sustain itself.

 

Also I'd worry about slag when the oil contacted the ash and carbon. Though I suppose I'd just have to clean it once and a while is fine to

Don't know your lighting procedure. Here is how it worked back when. Light small amount of paper in furnace, turn on fuel, and wait for it to light before turning on blower. The small amount of ash and leftover paper if any blows out of furnace when blower air comes on.

Doing it electrically I can see no easier way than the one suggested earlier with a oil furnace transformer. That is the only thing that is made to do what you want, you still have to figure out how to mount and make the electrodes, that can be the DIY part for you.

 

Don't know your lighting procedure. Here is how it worked back when. Light small amount of paper in furnace, turn on fuel, and wait for it to light before turning on blower. The small amount of ash and leftover paper if any blows out of furnace when blower air comes on.

Doing it electrically I can see no easier way than the one suggested earlier with a oil furnace transformer. That is the only thing that is made to do what you want, you still have to figure out how to mount and make the electrodes, that can be the DIY part for you.

If they aren't expensive then I'll get one. I've already got a concrete idea on the electrodes. That's the easy part.

 

As I'm sure you know oil burners are difficult to ingite cold even using heating oil. Years ago I had to fire off a kerosene-fueled forge and it was a real pain until the burner got hot enough to truly vaporize the fuel. Took a lot of kerosene-soaked waste paper/rags to do it. I'd be hesitant about using gasoline or even Coleman fuel which is a lot safer than gasoline. FWIW

 

As I'm sure you know oil burners are difficult to ingite cold even using heating oil. Years ago I had to fire off a kerosene-fueled forge and it was a real pain until the burner got hot enough to truly vaporize the fuel. Took a lot of kerosene-soaked waste paper/rags to do it. I'd be hesitant about using gasoline or even Coleman fuel which is a lot safer than gasoline. FWIW

I have a pretty firm grasp of its construction for safety. I'm not at all worried about flare ups or back pressure. Though I wasn't clear on gasoline preheat. I meant cooking oil thinned with gasoline to aid in preheat. Also it will have a preheat baffle toward the end to vaporize the fuel and prevent pooling. I've made them before and they've done great but I also had to use a bbq lighter or torch to preheat or a small tinder pile. I was hoping the igniter would help it to just be a bit less of a hassle to light.

 

Why not a heat tape wrapped around the oil supply lines? That would heat the oil in the line and may give it enough to start easier. The flash point is pretty low, "Number 2 fuel oil has a flash point of 52 °C (126 °F)"
From, https://en.wikipedia.org/wiki/Heating_oil


Or start on Kero and switch over after heat is built into the furnace. I'd never use gasoline.