Opinions on Gasoline Powered Forge

[zizicool1]

Good Afternoon everyone,

I'm a long time lurker of these forums, but I've never posted as most of what I was going to ask was accessible via the search bar. This is the one exception...I think.

Question:

What are your opinions of gasoline powered forges? I ask because I'd like to take my current gasoline furnace setup and reconfigure it to power a forge to start learning basic blacksmithing.

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My furnace at home gets to ~ 2500 degrees in ~30 minutes and is made from a full sized beer keg. It runs on compressed air and gasoline (the stuff in a car). It uses a Delavan siphon nozzle to generate and maintain the Air/Fuel Mixture (See attached picture). Aside from operator error and some design flaws, I've had no dangerous situations with it...yet. I ask specifically about gasoline because I've read about a lot of waste oils such as cooking oil, motor oil, and diesel. However, no one specifically mentions gasoline.

I wound up using gasoline because I got tired of swapping propane tanks in my area. It seems to always be a problem in good ole Augusta, GA.

Oh, yes I have the fully litany of safety gear and equipment such as: Respirator, Face shield, Flame retardant clothing, etc.

I'd love to hear your opinions on the matter before I start hacking away at a forge using the same technique.

Location:
Augusta, GA
 

 

 

[TWISTEDWILLOW]

What kinda mileage does it get? 

lol well I’ve seen diesel an waste oil forges but I’ve never heard of a gasoline rig, sounds kinda spooky to me,

Were you exchanging propane tanks or having them refilled? 

I don’t forge with propane but I do run bottle top heaters in the winter,

i know in my area I can take a grill size bottle an get it refilled for $10-$12 bucks vs $20-$30 at an exchange,

I only go there when I need to offload an old bottle I bought at a junk sale and swap it for something new  lol

[Frosty]

In my opinion a compressed air carbureted gasoline burner is too potentially dangerous to encourage at all. PERIOD. Do you know what a Fuel Air Explosion is? A couple fluid ounces of gasoline in a flammable air ratio will blow a house apart as in scattered pieces.

I understand exchanging cylinders if you're using one of the companies outside malls and super markets, it's expensive and more hassle than good. I exchange propane cylinders at Suburban Propane the company that supplies propane to most of our part of the state. They charge less than having a tank filled and I always get a tank with a good valve and current certification.  

Frosty The Lucky.

[TWISTEDWILLOW]

That’s interesting Jerry I never heard of an exchange cheaper then re filling,

I just buy the junky rusty old tanks here an there for a couple bucks and then exchange them for updated ones with the new style valves, and when the cert runs out I exchange them again,

[Frosty]

It's the local Suburban Propane outlet / yard. Their main refilling plant is only 2  miles from us but the main outlet stockpiles tanks. The last time I took a tank in to be refilled they directed me to the dock and rolled a full 100lb. tank into my pickup. If I take one to the place that fills it costs more than exchanging them at THEIR outlet. They refill hundreds a day at the "plant" but if you take one there to fill a guy walks out from the service station office and charges the same as any other service station. WORSE I've had to tell the attendant NOT to drain my tank completely so they can put more in it. It's not like I run them dry or am filling a brand new tank that needs the air purged. 

Exchange a tank at say the local Costco affiliate or Safeway and they cost about 2x what filling one does and a bit more than exchange at the Suburban Propane loading dock. 

Weldaire started exchanging rather than filling welding gasses a few years ago and you don't have to wait for them to haul in and out of Anchorage to fill. They  few hundred on hand at all times. My oxy bottle was pretty small I needed it to be fairly portable when I bought it, then same for the 75 25 bottle for my wire feed. Now my old bottles are long gone and I have larger ones. Same price as filling the original bottles. 

Everybody up here sells propane, there is too strong a tourist and camping market not to. Almost every service station has a tank and pumps propane but more and more Blue Rhino exchange lockers are showing up all over. It seems lots of tourists prefer to pay the extra to be sure of something. 

Frosty The Lucky. 

[zizicool1]

4 hours ago, TWISTEDWILLOW said:

What kinda mileage does it get? 

I think it roughly 1 gallon every ~3 hours at full blast. It takes some time to heat up though as it needs to be babied before I can increase the pressure.

I was going to Home Depot (and stores like that) to have it exchanged. At like $30 a refill, I was thinking there had to be a better way.



Is the Fuel Air explosion not a concern waste oil burners too?

Edited July 25, 2022 by Mod30
Trim quote. @name tag

[Irondragon Forge ClayWorks]

I'm with Frosty on this one. Gasoline is way to volatile to use in a forge. BTW: We won't remember your location once leaving this thread, hence the suggestion to add it in your profile.

[George N. M.]

Welcome aboard for 7500' in SE Wyoming.  Glad to have you.

If you put your location in your profile we will remember your location.  We will not recall it once we are off this thread.

I am in agreement that while a gasoline fired forge could work the voiatility of gasoine and its vapors make it more dangerous than other fuels.  Around here propane is still cheaper than gasoline, possible because you don't pay road tax on propane.

Fuel/air explosions can happen with any combustible vapor or dust.  Flour and grain dust explosions are a real hazard in the milling and grain storage industries.  A grain elevator blew up in South Chicago when I was a kid and it was a serious incident which demolished the elevator and killed several workers.  The more volatile a liquid means there are more vapors which can excape and form a potentially flammable/explosive mixture.

Gasoline has about 30% more BTUs per gallon than propane but I don't think that it would be cheaper per BTU and it is potentially more hazardous than propane.

So, could it work? Yes.  Is it worth the additional cost and risk? IMO, no.

Propane forges and other propane powered equipment are pretty much a mature techonlogy while a gasoline fired forge would be experimantal and the experiment could fail in a spectacular way.  Also, you might void your home's fire insurance by going forward with this.

I suggest that you call around to various propane dealers in your area to check on refill and exchange prices.  A quick google search shows a dozen or more propane dealers in the Auguata, GA area.

"By hammer and hand all arts do stand."

[Mikey98118]

I would choose even a coal forge before gasoline.

[Frosty]

Yes, fuel oil is a FAE hazard though it'd be more difficult to get waste oil to explode without serious negligence. I don't k now why but Home Depot ad Lowes are both more expensive Blue Rhino exchanges than the local convenience store Blue Rhinos. Even at the crazy high prices now, a 5gl tank exchanged at Suburban is about $17. maybe was, I haven't been in an a while.

Frosty The Lucky.

[ThomasPowers]

Here in a town of 10K people, (when the university is in session), there are a number of places to refill or exchange propane tanks. It is amusing to call and compare  the price per gallon for propane.   I refill and always used the same dealer for over a decade---they once came in when they were closed to fill my tanks when I was teaching on a weekend!   Unfortunately they were bought by a larger company based 80 miles away and no longer offer dock service.

Exchange places would often fill to a lower amount and then charge for a full bottle---there was a big class action lawsuit about that.  The refill places measure the propane by gallon and charge for what you get---I may refill a half dozen BBQ bottles and they just bill me for the total gallons.  (If you find a pace that has a standard refill charge abjure it!  Most times there is still some propane in the tank when it goes to be refilled.

[Latticino]

Another alternative would be to go over to natural gas.  It is pretty convenient, though you will need either a dedicated blower for a fan powered burner, or gas compressor for a NA one.. 

[zizicool1]

The risk assessment might not always be low on this one haha. I think I'm understanding the potential dangers of a gasoline powered forge compared to something like propane, waste oils, or diesel.

Because gasoline has such a low flash point, it is a perfect source for a fuel air (thermobaric?) explosion. It can build up in the air inside the forge, start to vaporize and collect, then explode when I light it.

Waste oils and diesel have a significantly higher flash points, so the likelihood of a fuel air explosion is reduced. It can still accumulate in the forge, but it will only light in vapor form at temperatures greater than ~520 F.

I'm essentially playing with fire if I use gasoline. Because it is so easy to light at ambient temperatures, all it takes is one mistake and BOOM. While diesel and other waste oils require significantly higher temperatures in vapor form to combust. Hell some might even start to boil before they combust.

If I'm not missing the mark too much here...I think I'll convert my furnace and forge to diesel and use a propane pre-heater. I really appreciate all of your feedback!

 

[George N. M.]

You may be able to reduce your costs with diesel by buying from a bulk dealer and certifying that you are not going to be using it in a vehicle.  Then, you are not charged the state or federal road tax.  This is common for diesel that is used in stationary equipment like generators.  The downside is that they may not sell in small quantities such as 5-10 gallons.  Like propane, call around.

"By hammer and hand all arts do stand."

[Frosty]

Please don't take this wrong but doing a little reading on line is NOT going to equip you to play with gasoline this way. A thermobaric explosive is a type of fuel air bomb, not all FAE are thermobaric any more than all pickup trucks are Fords.

Flash point is NOT what makes a FAE or furnace burner work, it's the flammable fuel air ratio. Volatility is what makes gasoline so dangerous, it evaporates very quickly and worse has a wide flammable air fuel range. Happily it's saturation point is above it's flammable ratio so it's possible for the vapors in a closed container to not be flammable. 

FAE works by carbureting the fuel into the atmosphere prior to ignition and no gasoline makes a poor FAE, kerosene is one of the best for a simple FAE. Oils have a higher energy density, more energy per gallon.

I'm not going to talk about thermobaric but it's not a buzz word that means you've researched the subject. This is too dangerous a topic for buzzword bingo.

Buy heating oil rather than fuel oil though you may need to convince the seller you aren't using it in a vehicle. Those are federal offenses and no distributor wants to flirt with the feds.

Frosty The Lucky.

[Irondragon Forge ClayWorks]

Most farm supplies will sell off road diesel in approved 5 gallon cans (Jerry cans), at least in my area. I buy it for the tractor that way.

[George N. M.]

Often gas and diesel sold for non-road use is dyed a different color than what you get at the gas station.  It is not an uncommon practice for a farmer to fill his car or pickup from the tank which is supposed to be just for farm machinery.  A different color fuel can quickly detect this.  There have been cases of folk doing this who have been assessed thousands of dollars in unpaid gasoline taxes.  A word to the wise.

In some states folk can use a common tank for machinery and vehicles but have to keep track of how much is used in vehicles and submit payment of the road taxes to the state.

"By hammer and hand all arts do stand."

[Mikey98118]

On 7/25/2022 at 12:32 PM, Latticino said:

Another alternative would be to go over to natural gas.  It is pretty convenient, though you will need either a dedicated blower for a fan powered burner, or gas compressor for a NA one.. 

Yes, and I think we need someone with some knowledge on the subject to start a thread on natural gas forges; they are only going to grow more popular as propane prices increase.