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Thread: Has anybody made a diesel gun?

  1. #41
    Boolit Master
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    Quote Originally Posted by mikeym1a View Post
    91% alcohol in a gun???!!?? That out to be in a glass!!!!!!!!!!
    Walgren's drug store sells 91% rubbing alcohol. It burns fairly good.

    You can increase alcohol content by placing a bottle in a freezer for several days, water will settle out and freeze into a layer of ice at the bottom of the bottle, what you pour off the top will be nearly pure alcohol.
    I've used a similar method to remove water from heating kerosene . I set a plastic container outside for several days in freezing weather till ice forms at the bottom. What rises to the top burns clean and bright in my oil lamps.
    Last edited by Multigunner; 11-04-2013 at 10:55 PM.

  2. #42
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    The trick would be to make an impulse gun like was mentioned earlier, similar to a Paslode. Pure oxygen and propane make a heck of a propellant, stoichiometric proportions could be accumulated and stored if not pressurized (bladder system?) per torch method and the combustion chamber purged with the mix after the projectile is breech-seated. The only issue would be spontaneous ignition from contact with oil, lube, or grease. Air/propane mix, obviously, would be much safer, and might be useful in a bottleneck-style combustion chamber to give a little longer impulse time and keep barrel pressure up.

    This would still be a firearm, but isn't it still legal to make one's own firearm provided it is never transferred or sold?

    Gear

  3. #43
    Boolit Master

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    Quote Originally Posted by geargnasher View Post
    .

    This would still be a firearm, but isn't it still legal to make one's own firearm provided it is never transferred or sold?

    Gear
    Most laws say a firearm uses fixed ammo, a cartridge containing powder, bullet and primer. The wording in some states has been changed to include antiques that use fixed ammo so rifles made before 1899 are now called firearms. Seems this was done under the radar.

  4. #44
    Boolit Master Garyshome's Avatar
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    I only have 150' of air hose, so I can use it in my yard but not much further.

  5. #45
    most of the more powerful springers already diesel to some extent. back in the day. HW made a gun that had an ether injector. the problem with dieseling all the time, is it eats the synthetic piston seals up really quick.

  6. #46
    Boolit Buddy Silver Eagle's Avatar
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    Keeping the velocity consistent would be a significant hurdle. Also, combustion requires fuel, oxygen and heat. Heat in a diesel operations would be provided for by piston compression. Fuel could be added in via injector or manual source. Oxygen might be the problem as the chamber would need to be vented and refreshed with fresh air after every shot.
    Wear and tear of parts (seals, springs, etc.) would also be a major stumbling block. A number of spring piston rifles have had the seals destroyed after one or two detonations. These can occur by using the wrong lube on the chamber or by dry firing.
    Have no idea what the BATFE would consider such an arm as it would be considered a "fuel" burner by definition.
    Silver Eagle

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  7. #47
    Boolit Buddy Driver man's Avatar
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    As a kid I used to put a squirt of ether in the dianna mk4 airpistol i had. Used to blow it open sometimes but wow. Learnt how to make leather piston seals,spring compressers and bandages.
    The Bird of Time has but a little way
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  8. #48
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    Quote Originally Posted by starmac View Post
    Yea it would down right suck for your diesel to gell up while you had your sights on that trophy buck. lol

    We used accetylene and oxygen in them potato guns. lol
    Years ago I made a accetylene and oxygen cannon for golf balls.... Mother Mary did they go fast..........

  9. #49
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    Those "Big Bang" cannons sold in comic books used a calcium carbide/acetylene charge for their bang (calcium carbide + water=acetylene). Was there a way you could fire a projectile from them?

  10. #50
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    Quote Originally Posted by Speedo66 View Post
    Those "Big Bang" cannons sold in comic books used a calcium carbide/acetylene charge for their bang (calcium carbide + water=acetylene). Was there a way you could fire a projectile from them?
    Heck yes, we used to fire small pine cones, before fully open, from ours.
    The VA says I'm only a Vietnam era veteran because my ship didn't roll on RVN land and my boots only walked on non-skid. So the Agent Orange sprayed on me off Song Ong Doc doesn't count! The VA - making sure all US veterans die for their country.

  11. #51
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    You Gize need to think Outside The Box, on Diesel Powered Rifle, you need to use a Glow Plugs, plus a Mechanical Diesel Injector.

  12. #52
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    I have a buddy who diesels his spring cocker air gun. he packs a pellets skirt with Vaseline and fires it the compression ignites the vaseleine or mix he uses and gains him another 200 fps or so. I have heard of lighter fluid being used also for this. All admit its hard or the air rifle and greatly lowers its life.

    A rifle could be built to do this and some in the past have been close, caseless ammo is one that comes to mind. a simple chamber with throat for the bullet to be seated into to seal chamber. A known space for the desired liquid and amount ( diesel fuel, Vaseline, lighter fluid). Then the compressed air charge or piston to get the 25-1 or so compression to fire it. I would think ignition with some base materials would be iffy and lock time would be slow.

  13. #53
    Boolit Buddy AllanD's Avatar
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    Quote Originally Posted by W.R.Buchanan View Post
    OK guys,,,, The German Company Weihrauch who makes a lot of the good Spring Piston air guns once produced a version of the HW35 in .22 cal. know as the Barakuda.

    http://www.pyramydair.com/blog/2006/...l54-ether.html

    It was a normal HW35 in .22 cal. with an attachment that dispensed a drop of ether behind the pellet just before you fired the gun.

    It produced .22 LR velocities from a gun that normally had 580 fps velocities in .22 cal.

    So the short answer to the OP's question is . It was done in the late 60's early 70's.

    They used Ether as the propellant due to its low flash point. IE the compression of the piston in the gun easily ignited the ether.

    On a side note: There are Diesel Model Airplane Engines that have been around from the beginning. In fact most European Model Airplane Engines are Diesels.

    They run on a fuel made of 33% kerosene, 33% Ether, and 33% Castor oil.+ some traces of some additives I have forgotten.

    These engines are compression ignition engines and the combustion chamber is adjustable to cope with ignition timing and actual compression. They end up running in the 9:1 Comp ratio regime due to the inclusion of Ether in the fuel which lowers the flash point of the fuel mixture.

    These engines are about 1.5 times the horsepower of a similar displacement Alcohol/Nitro fueled Glow Ignition style engine common here in the US. This mainly due to the higher density of the Kerosene. The ether is in there to start the fire easier.

    This is also the reason why diesel engines produce more power than gas motors. Normal gasoline is around 10,000 BTU's per pound. Diesel fuel is 18,000 BTU/LB. Kerosene is even higher and that's why they use it as Jet fuel.

    It is easy to see this if you look at the structure of the individual molecules of fuel. Natural Gas is CH4 "Methane" that is one carbon atom with 4 hydrogen atoms surrounding it. Gasoline is 6,7,or8 carbons lined up IE: Sextane, Septane /Heptane, Octane, with 14, 16 or 18 H's around. Diesel is 12,13,14 carbons and 26,28,30 H's and kerosene is 20-40 C's in a row, with 42- 82 H's !

    It is easier to see how these denser fuels have more poop. This is why 75% of the cars in Europe are diesel powered. VW Jetta wagons have a 2.0 L engine that produces 140HP and gets 42+ mpg. A new 2.8L BMW engine in the 3 series cars is 280HP and yields 45 mpg. Looking at one of those later today or tomorrow.

    This is why I own diesel powered vehicles.

    Randy

    Actually alcohol free Gasoline is about 22,000BTU/lb.
    the difference is that gasoline under compression burns much faster and less "progressively" than Diesel fuel, plus Diesel is added progressively to an already ingnited cylinder. Diesels make more torque than gasoline engines because of their longer Stroke, not because of any inherent characteristic of the fuel
    Add to this discussion that the new crop of "Gasoline direct injected engines" are erasing the advantages of diesel engines.

    The difference between gasoline and alcohol is rather profound Hydrocarbons such as Propane. Gasoline, Kerosene and Diesel all have near enough to 20,000BTU/Lb to not make a difference while alcohols have 10,000-12,000BTU/LB

    NTW, diesels DO NOT MAKE MORE POWER than Gasoline engine, often for a given displacement that produce around 60% as much, but they do for a given displacement produce more torque, but you are "All wet" on your quotes of chemical energy contained in the fuel...

    To get this back to firearms related do you know what the specific energy of our favorite propellants are? GOOD Black powder is about 300,000BTU/lb, and nitroglycerine is closer to 1,300,000BTU/lb, Nitrocellulose lies at about 700,000BTU/lb



    BTW, what most people think of as "Ether" (Aerosol "Starting Fluid") isn't
    Aerosol starting fluid is usually a mix of "Pentane" (the five carbon hydrocarbon) with a mix of Butane (Four carbon) and propane (Three carbon) as "propellant"
    Last edited by AllanD; 04-19-2019 at 02:36 PM.

  14. #54
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    The old Webley Mk 2 air rifle from the 1930's used proper little bronze split piston rings - that would solve your seal burning problem. I would think a much smaller piston/cylinder would be better. Compare the swept volume of a modern spring airgun at around 6 cube inches to a model plane engine at about .3 cube.
    Fuel induction could be like a two stroke engine, on the cocking stroke a loading tap opens ( as on older BSA Airsporter underlevers) this will create a vacuum as the piston is drawn back until it uncovers the fuel induction port. A simple model plane engine carburettor would meter the fuel.

  15. #55
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    My can of starter fluid states it contains 25% ether ,rest as petroleum fractions...........anyhoo,you might be better off with something like nitrobenzine ,which is available for model planes .....another used is isopropyl nitrate ,used in diesel fuel at sub zero temperatures.(jet kero actually,diesel is solid at sub zero temps).

  16. #56
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    if you want see something like a diesel airgun.a diesel piledriver works similarly,but weighs many tons,so the size of components isnt a problem.

  17. #57
    DOR RED BEAR's Avatar
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    I have seen and read things on both sides so not sure who is right. Some say the increase in performance is astounding others say it is next to nothing. Heard it will destroy seals others say its not a problem. every one i say used something along the line of Vaseline. I would love for someone who actually does it to post results velocity increase what caliber and gun ect.

  18. #58
    Boolit Grand Master GhostHawk's Avatar
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    IMO silvereagle nailed it. Trouble is consistency. Getting the exact same pressure, fuel, temp the same every time is going to be tough. Change any variable by any significant amount and you could be changing your trajectory.

    Powder is easier.

  19. #59
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    Quote Originally Posted by RED BEAR View Post
    I have seen and read things on both sides so not sure who is right. Some say the increase in performance is astounding others say it is next to nothing. Heard it will destroy seals others say its not a problem. every one i say used something along the line of Vaseline. I would love for someone who actually does it to post results velocity increase what caliber and gun ect.
    Personally I don't think there's any future in it - other than an interesting and challenging project. - What exactly would be the aim?
    More power? Modern spring air guns are quite commonly available in the 15-20ftlb range, PCP's anything from 6 to 100ftlb where you are firmly into .22lr territory.

    You certainly won't gain any accuracy - modern air rifles are just so consistent in power, a spread of 5fps is not unusual.

    The concept would fall into various restrictions - seen as a firearm in many places, if not currently it's coming.

    If you're looking for something to bridge the gap between a standard air rifle and a .22 short you could very easily convert a fairly low powered air rifle to shoot .22 button blanks which will drive a heavy
    pellet up to 20 ftlbs.

    That's no to say it's not an interesting project for it's own sake.

  20. #60
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    Hah! I missed this thread when it started way back!

    I too used to put a drop or two of light oil in my old spring cocker and got fairly dependable dieseling. I'm sure velocities weren't consistent but when it went there was a sharper crack and much more impact evident.

    There was a commercial version of a diesel gun I saw and almost bought back in the 70's. ! don't recall the manufacturer but thinking Diana or Weihrauch... or at least European. It was a modified spring gun with a manual ether injector on it. It had a small cylinder on the right side that you put ether into and a little manual piston put a bit of ether into the compression chamber when operated. Seemed like an interesting idea but more trouble than it was worth. And as said, modern air guns are miles ahead of air guns then so little point now I think.

    Hah! There we go: https://www.pyramydair.com/blog/2006...ion-air-rifle/ my memory isn't as bad as I thought! These were apparently in production for quite some time.

    Longbow

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Abbreviations used in Reloading

BP Bronze Point IMR Improved Military Rifle PTD Pointed
BR Bench Rest M Magnum RN Round Nose
BT Boat Tail PL Power-Lokt SP Soft Point
C Compressed Charge PR Primer SPCL Soft Point "Core-Lokt"
HP Hollow Point PSPCL Pointed Soft Point "Core Lokt" C.O.L. Cartridge Overall Length
PSP Pointed Soft Point Spz Spitzer Point SBT Spitzer Boat Tail
LRN Lead Round Nose LWC Lead Wad Cutter LSWC Lead Semi Wad Cutter
GC Gas Check