Jump to content

diesel forge


KPeacock

Recommended Posts

Due to my lack of patience, I made a crude attempt at a diesel forge my modifying a forced air propane forge that i have built. I get the forge hot using propane and then decrease the propane and add a diesel drip to the air inlet. The forge works and is sustainable on diesel fuel alone....but it will require some fine tuning. I've got too many other projects right now to really work on it and at shut down, the diesel fumes are not very pleasant in an enclosed shop. This spring I want to make a dedicated diesel forge that is purpose built. I'm not sure if it will reach welding temperatures, but I'd like to find out.

 

My diesel feed system is simply a gravity feed set-up with a valve off of an extra oxy-acetylene torch set-up to control flow. the fuel then travels through a small hose into a 1/4" pipe nipple that is threaded into the air inlet of the forge. Nothing fancy,but it "sorta" works. I believe I'll need to use a 1/8" nipple tapped to accomodate a MIG tip in order to keep the fuel from dripping on to the walls of the air inlet. It's still very early in the design process, but it looks promising :-)

Have you ever thought about the life of steel? It's interesting to think that you can control the fate of a piece of metal.

Link to comment
Share on other sites

There are plenty of btu's for getting to welding heat. It is just a matter of getting a good burn going. Diesel fuel will get hotter than propane if the fuel/air mix is right and the fuel fully atomized into the air stream. Used motor oil is hotter yet, because of the metal particles in it. Both are more trouble than propane, but less money, maybe. Diesel is high here still.

 

Used vegetable oil would run a forge as well as diesel if the forge were first pre-heated with propane, I think. Plus it would smell nice. :) You would still have to do the bio-diesel refining to get the glycerin out to make it flow in weather like this though, or heat the fuel tank.

Link to comment
Share on other sites

Diesel is around $2.20 near me, which seems reasonable. I'm not sure what type of fuel quantity I'll end up consuming, but my guess is that it'll be cheaper than propane i nthe long run. if nothing else, I won;t have to worry about running out of fuel. I always have plenty of diesel on hand for a tractor. In addition, i can buy diesel within 1/2mile of my home. The nearest place that will fill a 100# propane tank for a reasonable rate is about 12 miles away, and not in a direction that I typically find myself traveling.

 

Whether this diesel forge nonsense proves to be worthwhile or not is still a mystery. To me, it's worth trying simply to satisfy my curiousity.

Have you ever thought about the life of steel? It's interesting to think that you can control the fate of a piece of metal.

Link to comment
Share on other sites

Kevin,

 

The oil forge I built produced literally frightening amounts of heat, and the interior could get blinding yellow-white when it was running well. (That was true whether I was ran it on WMO, WVO or diesel). You should have no trouble reaching welding heat.

 

As you've discovered, it's getting the things to run reliably without too much fussing over them -- especially if you want to burn oil from a cold start -- that's hard. Some folks have had luck converting residential gun-type oil burners to burn waste oil for purposes of firing melting furnaces; I have to believe they'd work in forges as well. You can sometimes get used burners free from places that install and service oil furnaces. I was able to get a completely functional burner from the scrap pile of such a place (with permission).

Edited by Matt Bower
Link to comment
Share on other sites

IIRC, the trick with any oil burner is atomizing the fuel - I saw a desgn for a low pressure burner where the oil was dropped onto the top of a sphere that had a slot cut at the equator - the oil film flowed down to the slot then was dispersed for combustion - this was a long time ago though in Pop. Science. Low pressure air was all that was needed - you did not need to presssurize the oil.

 

One oil burning stove design I saw [for arctic use] had plates of steel that were sloped and staggered so that oil would drip down the plates and burn as it flowed down the plates - never saw that in operation but it looked interesting in concept. This had a hopper that held whole slabs of blubber that were rendered and burned by the heat of the stove.

 

As far as temps, I'm sure oil will get at least as hot as propane if properly burned but odors are another matter, as well as firing soot and the like.

Link to comment
Share on other sites

Eric,

 

I am familiar with the design you're refering to. It may be necessary to go that route, but i believe it to be possible to atomoze fuel using little more than the heat of the forge itself. With a propane burner in place, welding tempr, or very near them, can be achieved before adding diesel. My theory is that the diesel can be dripped into the forge and will be evaporated (atomized) but the heat of the forge. The atomized fuel is then burned. It seems to me like there must be some minimum fuel flow rate to sustain this reaction. I'll have to dig out some of my old thermodynamics and ehat transfer books to recall the specific heat of diesel and is boiling point...etc.

 

I'm encouraged by the early results and am quite eager to continue expirimenting. The wife demands that I repair her snowmobile before I "play with hammers." So I must take care of that first. I would be more comfortable doing this type of expirimenting outdoors as well. Minnesota is no the best place to be outdoors tinkering in January. I'll keep the board posted though. If this works as well as I think it will, I believe forges can be made simpler for newbies like myself.

 

It is truly amazing how addictive this hobby is. Just a couple of months ago I was excited to have made a charcoal forge. Now I've made 2 solid fuel, two gas forges, and I'm expirimenting with liquid fuel. It makes me curious as to what devices I'll create/duplicate in the months to come :-)

Have you ever thought about the life of steel? It's interesting to think that you can control the fate of a piece of metal.

Link to comment
Share on other sites

IIRC, the trick with any oil burner is atomizing the fuel,

 

The simplest approach to atomization is heat. Even large drops of oil hitting a 1500 degree atmosphere will instantly flash to vapor and burn, as long as you provide enough air. Injector burners that rely on that principle, including the one Kevin built, as well as the ones I've built , require a preheat by some fuel other than oil. Once the chamber is hot, you can switch to oil and the flame will self-sustain. But if you want it to burn oil from a cold start you need something a little fancier.

 

I saw a desgn for a low pressure burner where the oil was dropped onto the top of a sphere that had a slot cut at the equator

 

Sounds like a Babington burner, which is something I've been wanting to experiment with. I have the atomizer ball with two 0.010" holes drilled in it (you can use holes or a slot), but I haven't worked with it yet. (The one at that link is producing a fairly lazy flame; I think the fuel and air need better mixing. It's possible to do much better.)

 

As far as temps, I'm sure oil will get at least as hot as propane if properly burned

 

Hotter, in my experience.

 

odors are another matter, as well as firing soot and the like.

 

A clean or slightly reducing burn really doesn't produce any odor or soot to speak of. But in the cruder designs like mine it's pretty easy for the burn to get heavily reducing very fast, which makes it look like a plane crashed into my house. This is why I use propane at the moment; I can't believe the neighbors never called the fire department on me. But I'm still very interested in better oil burner designs.

 

The stove design you saw sounds similar to the Mother Earth heater.

Link to comment
Share on other sites

The wife bought a fry-daddy and now I have gallons of WVO sitting around just waiting for me to play with it :) I was thinking of running a copper line into the burner pipe near the burner outlet. With my forge, the burner pipe near the forge gets plenty hot and I figure if I get the drip rate set right with a needle valve, I can use a ball valve as an on/off switch. I'm of the opinion that simple is good (if not best). The BP ought to vaporize the oil and the blower would inject it into the forge, just like it does with the propane... the welding tip is a really good idea that I might steal if I get this project started.

Kristopher Skelton, M.A.

"There was never a good knife made from bad steel"

A quiet person will perish ~ Basotho Proverb

Link to comment
Share on other sites

My theory is that the diesel can be dripped into the forge and will be evaporated (atomized) but the heat of the forge. The atomized fuel is then burned. It seems to me like there must be some minimum fuel flow rate to sustain this reaction.

 

This is not a theory; it's a fact. It's how my oil burner works, and if yours is anything like mine, and Lionel Oliver's "Brute" (it is, isn't it?), it's how yours works, too! There is some minimum flow rate, but it's really not that high; once you reach a temperature that'll flash you oil to vapor, all you need to do is provide enough BTUs to replace the ones being lost out the openings and through the shell. Of course if you want to make the forge hotter you'll have to add more. B) I do find that with these sorts of burners it's easier to maintain balls-to-the-wall temperatures than to cruise along at 1500 or so, but I think that has a lot to do with the crudeness of my construction.

Link to comment
Share on other sites

I only have trouble with my WMO forge if there's a lot of wind. Cold (well cold in Alabama) temps, moderate winds... nothing seems to phase it. I just drip oil into the end of the burner tube and the blower blows it into the forge body. I do agree that low temps are harder to keep even than the 4th level of Hell fires that are easily possible.

Link to comment
Share on other sites

Matt,

 

The second link you provided is fantastic. That essentially what I"m doing with my set up. It appears to be working very well for that fellow. I believe it may work better in a vertical forge than in a horizontal forge. Any unburned fuel would be pulled by gravity to the bottom of the outfit when it would contact the hot walls of the forge and vaporize. It looks like I might have to go ahead and make a vertical forge as well :-) I'm beginning to find that, although I can realistically only use one forge at a time, I have a great desire to have more and more forges.

 

Mike blue hit the nail on the head when i was picking his brain for ideas. When asking him what type/style of forge is "best" he simply said "It doesn't matter. You'll build more than one." I thought that a bit odd at the time as I only needed one forge, one hammer, and one "anvil" to make a knife. For me, it's almost as fun making the tools of the trade as it is making the knives.

Have you ever thought about the life of steel? It's interesting to think that you can control the fate of a piece of metal.

Link to comment
Share on other sites

Hmm. Interesting. I never considered the impact of forge design. I've only ever used my oil burner in a vertical forge -- a huge one made from a 16 gallon oil drum! Maybe that does make a difference.

 

For me, it's almost as fun making the tools of the trade as it is making the knives.

 

I know how you feel. I myself have a problem fiddling with and making tools and equipment to the point that I sometimes forget to actually, you know, put them to use.

 

Now that I have a compressor, one of these days I'm definitely going to be play with atomizer designs. There's an awful lot of potential there.

Link to comment
Share on other sites

Have you folks seen this one?

 

Torch_Plans.jpg

 

( My appologies if the photo is oversized - I am trying to figure out how to resize it. )

Once you can accept the universe as matter expanding into nothing that is something, wearing stripes with plaid comes easy.

Link to comment
Share on other sites

Greg, I have seen that. I appreciate you posting this, because I was looking for that article recently and I couldn't find it on the 'Net to save my life!

 

I've run into some folks who claim to have tried this design, and they say it's not nearly as easy as the article makes it out to be. And there are lots of other, much simpler, proven designs out there now. But the basic theory behind this one is sound.

Link to comment
Share on other sites

Matt,

 

Do you have links to the other designs?

 

I have been looking, but I keep running in to the same old stuff.

 

 

I would just as soon try and stay away from the 'drip' type so I have been kind of looking at one that heats the fuel to vaporize it - but the ones I have seen still must be slightly pressurized to work.

Once you can accept the universe as matter expanding into nothing that is something, wearing stripes with plaid comes easy.

Link to comment
Share on other sites

The problem with vaporizing the fuel is that it's going to coke up the fuel line. I have a hard time envisioning a system that creates hot oil vapor but doesn't produce coke. Maybe I'm just not imaginative enough.

 

Here's an approach that seems to really please a lot of people. The only down side is that it requires an air compressor (but so does that air-diesel torch -- like I said, same principle): http://backyardmetalcasting.com/forums/viewtopic.php?t=2801 When I get a few moments I think I can make a rough equivalent out of some copper tubing, some standard brass plumbing fittings and a MIG tip.

 

Also look around at this link. I'd be more specific, but I can't access the page from behind my office web filter. I can only give you the main link: http://daggoth.smugmug.com/gallery/2732499_qpVrS The one with the two intersecting, brazed-together brake lines is dead simple. (Again, same principle as the air-diesel and the previous one.) It'd probably work a little better if the fuel were injected through the center of a turbine blade arrangement to achieve better mixing. (But it seems to work pretty well as-is.)

 

Here's one that's mid-way between the venturi/siphon approach of the air-diesel and those previous two links, and the drip type burners that you (and I) don't especially like: http://backyardmetalcasting.com/forums/viewtopic.php?t=3022 No compressor required, but you need a fairly ballsy blower.

Edited by Matt Bower
Link to comment
Share on other sites

Here's one that's mid-way between the venturi/siphon approach of the air-diesel and those previous two links, and the drip type burners that you (and I) don't especially like: http://backyardmetalcasting.com/forums/viewtopic.php?t=3022 No compressor required, but you need a fairly ballsy blower.

 

Matt, I'm running a smaller variation of this burner with a fairly small blower. I'm using 1 1/2" for the burner tube instead of the 2" mainly because the blower matched up well to it. I have no problems getting welding temps with this burner.

Link to comment
Share on other sites

Ahhhh... I obviously misunderstood :)

 

Loisandladyknives (Chuck) on here built a WO forge similar to mine, he just called and told me he melted a bar of 5160 on accident. His father or father in law mentioned that they used the same burners in a foundry he worked at. :) I warned him that welding temps are easy, it's hard to back it down for forging :P

Link to comment
Share on other sites

The problem with vaporizing the fuel is that it's going to coke up the fuel line. I have a hard time envisioning a system that creates hot oil vapor but doesn't produce coke. Maybe I'm just not imaginative enough.

 

I actually ran into a solution of that problem in an old issue of Pop Mech for just these types of burners - don't worry about coke formation, as a part of routine maintenance, just detach the nozzle and thread a piece of speedometer cable through it with a small brush on the end and attach the other end to a drill - turn the drill on a let the cable/brush clean it out.

 

As to needing a blower with a bit of umph, I have the blower that used to push air through my home heating system - thing must weigh in around 20/30 lbs with the motor - I imagine that constricted down it will provide a fair amount of draft.

Edited by Greg H.

Once you can accept the universe as matter expanding into nothing that is something, wearing stripes with plaid comes easy.

Link to comment
Share on other sites

Loisandladyknives (Chuck) on here built a WO forge similar to mine, he just called and told me he melted a bar of 5160 on accident. His father or father in law mentioned that they used the same burners in a foundry he worked at.

 

Yeah, I melted some 304 stainless when I first started playing with oil.

Link to comment
Share on other sites

For good info and domo on a used oil burner forge, go over to you-tube and watch Trent Tye and his air assisted propane/used oil forge in action. Purgtory Ironworks.com

 

 

Yep, that looks just like the first two oil burners I used. They're ridiculously simple, and they sure do pump out the heat.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...