Working Logan's Run DS gun. Small torch vs. chemical reaction?

Rob Skramstad

New Member
I remember missing out on an opportunity to pick up one of Rylo's working DS guns many years ago, which still stings as it's one of my "holy grail" props. Missed the Palmetto EFX version, too. Born under a bad sign, I guess. /whine

There are movies I like better than Logan's Run, and weapon props I like better than the DS gun from a form perspective, but there's no prop replica I've ever come close to wanting as much as an actual, working, flame-producing DS gun.

The original prop itself, and the working replicas I know of operate on the reaction between Calcium Carbide and water, which produces acetylene that is then ignited by the glow plug. Very cool, cutting edge at the time, and authentic to the original.

These days, however, small acetylene torches are so common that they make kitchen versions to caramelize the top of your dessert. Couldn't a small torch like that be gutted and its innards repurposed to produce a less authentic, but much simpler and probably safer, working DS gun? Particularly given the nice, metal DS gun kits that are available today?

I've been thinking about this for awhile but have neither the engineering chops nor the building skills to pull it off myself, and wondered whether someone smarter than I had any thoughts on the idea.
 

Rob Skramstad

New Member
Such is my mania for someone to build one of these things (to sell to me :)) that I've kept looking into this and a small acetylene torch is probably a dead end as there aren't any torches or canisters small enough to fit without dragging around a hand truck. Unless of course someone knows how to refill those little CO2 canisters that pellet guns use or NO versions for cream whippers, with acetylene.

However, those small kitchen torches still seem promising to me, but I now know that they use a different chemistry and I've no idea whether they can reproduce the same effect, even if they could be adapted.

Most use butane under high pressure, and appear small enough to fit within the available weapon kits, perhaps with modification. They even have their own ignition systems, which could reduce complexity by reducing the glow plug from function to form.

Obviously without onboard acetylene and a working glow plug authenticity to the original is compromised, but if the goal is simply to produce a replica that's externally and functionally identical if mechanically different, it seems like it would work, and again probably be safer than the film version.

I can't post links yet, but I was looking at the BernzOmatic site and Amazon, and there are plenty of very small butane torches that look like they'd be suitable candidates, particularly after all the consumer-friendly brightwork and kitchen-purposed parts are stripped off.

Can someone with experience with the prop itself, or the chemistry and/or engineering let me know if I'm onto something or whether there's some crucial detail I'm missing? If not, I'm reaching the state where I'm considering taking a crack at it myself even though I'm probably the least likely person on the planet to pull it off.
 

Apollo

Legendary Member
RPF PREMIUM MEMBER
No engineering or chemical degree here but Butane is completely different than acetylene.

With that being said the key to that prop is the valve and that is where you are going to run into problems
 

laellee

Master Member
RPF PREMIUM MEMBER
Completely agree, the valve is going to be the crux. Maybe look into the momentary pneumatic valves used in airsoft guns?

Side note Rob, Rylo = Palmetto Effects, so you only missed out on one there ;)
 

Funky

Master Member
RPF PREMIUM MEMBER
I have nothing constructive to add but I did want to bring something up.
I may be wrong but I don't think Rylo will respond to this thread. The reason?
Liability.
What you're attempting to do could go south real quick. Unless you have a solid working knowledge of gasses and valves and how things work with each other, what you're attempting is risky. Personally, I would be fearful of giving advice or opinion in case I'm wrong and you try it and it explodes and burns your face off, I don't want to be responsible for giving my theory of what "might" work.
Now, if you want advice on what to do with a leaching piece of resin, I'll shoot off my mouth all day long!
 

TazMan2000

Sr Member
Yep. Even these blueprints mention the same thing.

LoganBlueprints.jpg



Acetylene and butane? Dangerous stuff. How about an LED illuminating a puff of smoke or steam?

TazMan2000
 

Duncanator

Sr Member
Fire bad!

Fire.jpg

Especially if you don't know what you're doing. High pressure vessels are also dangerous. Think seriously about how you want to go about this and/or hire someone who does. I'd hate for you or someone else to get hurt.
 

Rob Skramstad

New Member
Hi, folks. I wasn't asking for anyone's response specifically, although I'm glad I now know that Palmetto and Rylo are the same, as I was thinking I'd missed two opportunities, which really made my brain itch.

And I'm aware that butane and acetylene are very different gases, yet operationally, torches based on both seem to my untrained eye to operate similarly and produce similar results. I'm only looking for information from folks who know something about the subject matter, because I simply don't. I know that there are a lot of builders on the forums with welding and engineering experience, and their input - conceptually and factually only, would enlighten me about stuff that's way outside my wheelhouse.

Thanks for pointing out the potential liability concern, which I hadn't thought of. My view as a lawyer is that I don't see any liability attaching merely to the disclosure of facts or responding to my questions. Were it otherwise, the mere distribution of the schematics of the original would also result in liability. And if I could actually get someone to build one for me, I'd be willing to provide the most ironclad and comprehensive release document I (or the builder's lawyer) could manage to construct.

However, at this point please also be clear that I am NOT asking and DON'T WANT anyone to actually try or do any actual work on this, conduct any experiments that might result in their own injury or property damage, or indeed to do anything but provide knowledge I've requested. If someone raised a hand to do anything me, or actually build me a gun, they and I could deal with how to proceed to make them comfortable.

Anyway, to the extent liability is indeed a concern to anyone who might otherwise reply, I state that I know that producing a working flame gun is inherently risky and dangerous, that I am aware of the risks of fire, explosion, personal injury, property damage and/or death resulting from work with flammable gases of any kind, torches and other devices that contain or dispense such gases, and/or any attempt to retrofit any gas-based torch or similar system into a flame gun model, including any attempt by me to produce such a flame gun based on any such torch, similar tool, flammable or explosive gas and/or any other other associated dangers. I voluntarily assume these risks and do moreover and forever agree, on behalf of myself, my executors, heirs, and assigns, to defend, indemnify, and hold harmless any person providing purely factual information responsive to my inquiries from any liability resulting from my use of such information, including but not limited to my suffering any personal injury, property damage, or death.

The irony here is that the main reason I'm trying to determine feasibility is specifically because I believe such a system would be significantly safer than the method used in the original, which is just plain scary (although I'd still buy one in a heartbeat). I'm simply not a builder, or at least not a good one. I love to build models with plastic, paint, and glue, and airplanes and helis with nuts, bolts, and screws, but they're not pretty.
 

Rob Skramstad

New Member
No engineering or chemical degree here but Butane is completely different than acetylene.

With that being said the key to that prop is the valve and that is where you are going to run into problems
Thanks for this note, which I forgot to address. I agree that the valve would be key, but wouldn't such a valve be built into whatever torch or other device that would dispense the gas? My whole goal with this brainstorming is simplification, which should result in improved safety. But, again, I just don't know and am trying to draw on the experience and knowledge of those who do.
 

Apollo

Legendary Member
RPF PREMIUM MEMBER
Not necessarily the originals failed due to using the valve they used it could’nt handle what they wanted it to do.

JJ’s guns suffered the same fate from what I have heard.

Ry really did one miraculous feat of engineering on his last Run as he basically redesigned and updated some key inner workings of the Gun, including a custom made valve.

It is a shame Fred Cramer had passed away, as it would have been nice for him to look over one of Rylos Guns

He would have appreciated what was done with it.

I think the “Danger” of this gun is being a bit over played here which is not a bad thing I suppose as it could be inherently dangerous in someone who does not understand it or is indeed careless with it.

I have no fear of mine, I shoot it off 2 or 3 times a year and have never had a problem with it.

Looking forward to see what you come up with!


Thanks for this note, which I forgot to address. I agree that the valve would be key, but wouldn't such a valve be built into whatever torch or other device that would dispense the gas? My whole goal with this brainstorming is simplification, which should result in improved safety. But, again, I just don't know and am trying to draw on the experience and knowledge of those who do.
 

Funky

Master Member
RPF PREMIUM MEMBER
I think the “Danger” of this gun is being a bit over played here which is not a bad thing I suppose as it could be inherently dangerous in someone who does not understand it or is indeed careless with it.

I have no fear of mine, I shoot it off 2 or 3 times a year and have never had a problem with it.
Please don't downplay this. As I said, if you don't know what you're doing, this could go south real fast. I know we don't always see eye-to-eye, but I don't want anyone getting hurt.
 

Apollo

Legendary Member
RPF PREMIUM MEMBER
Not downplaying a thing Armando, as I posted it could be dangerous for someone who does not understand the gun or is careless.

Rob seems smart enough to be cautious about this


Please don't downplay this. As I said, if you don't know what you're doing, this could go south real fast. I know we don't always see eye-to-eye, but I don't want anyone getting hurt.
 

Funky

Master Member
RPF PREMIUM MEMBER
Not downplaying a thing Armando, as I posted it could be dangerous for someone who does not understand the gun or is careless.

Rob seems smart enough to be cautious about this
Fair enough.
 

Sean

Sr Member
RPF PREMIUM MEMBER
I attempted year's ago to make a working deep sleep gun. The valve I found and used was too big for the frame of the gun. So I altered It. Big mistake It leaked. Flames came all the way from the glow plug the the valve leak by my hand. Thankfully I wasn't hurt. I later added to the gun a machined brass mixing chamber. Then It became quite clear how dangerous somthing like this could get If not done professionally. My potentially very dangerous attempt was put away. Wouldn't try to fire It now Unless remotely triggered behind bullet proof plexy. So Is It worth It. Hell no
 

Funky

Master Member
RPF PREMIUM MEMBER
I attempted year's ago to make a working deep sleep gun. The valve I found and used was too big for the frame of the gun. So I altered It. Big mistake It leaked. Flames came all the way from the glow plug the the valve leak by my hand. Thankfully I wasn't hurt. I later added to the gun a machined brass mixing chamber. Then It became quite clear how dangerous somthing like this could get If not done professionally. My potentially very dangerous attempt was put away. Wouldn't try to fire It now Unless remotely triggered behind bullet proof plexy. So Is It worth It. Hell no
Thank you, Sean. That's exactly the point I was trying to make. I'm glad you weren't hurt.
 

TOKI

Well-Known Member
RPF PREMIUM MEMBER
Rick Ross did one, and I'm lucky enough to have it. He used a beefed up valve which has never leaked on me, not sure how he did it. He also developed a mixing chamber which kept the CC and water separate until after it was sealed. As for the original props, Michael York told me that they leaked horribly, his hand was constantly engulfed in flame, never any harm, though.
 

Rob Skramstad

New Member
Cool idea, Propmaster.

And thanks for your concerns, folks. I sincerely appreciate it. I know this is a dangerous endeavor and I'm very aware of my own limitations, which is why I've been so hesitant to try it myself.

And again, this idea was born as much as a means to working out a safer way of doing this than methods used in the past. I have a strong general preference that my prop replicas not be subject to sudden, catastrophic failure - with explosion and electrocution being at the top of the failures-to-avoid list.

Moreover, I've an unhappy relationship with fire in general. The worst example is the 6 square inch skin graft from the time I poked at a fire and accidentally broke a log, which promptly rolled out of the fireplace, up my shoe, and lit my sweatpants, which were apparently made primarily of napalm, on fire.

Optimally, I'd like to avoid this kind of excitement.

Here's the sort of torch I'm thinking of, although there are thousands of these in almost as many configurations: https://www.amazon.com/Forte-Torch-Soldering-Jewelry-Torch-Kitchen-Adjustable-Flame-Security/dp/B07DMBDCCP?th=1.

Doesn't this solve the valve problem in that it's already machine-built, UL listed, and trigger-operated? The remaining challenges (and I freely admit I could be overlooking others obvious or subtle) would be maintenance of a pressurized fuel canister in the grip, a good supply line from the fuel to the valve, and a linkage between the trigger on the gun and the trigger on the torch.

I've already acknowledged that I'd have to study hard even to become a layman on building something like this, but it seems to my untrained eye to be very workable by someone with the right chops.

Am I missing something?
 

Apollo

Legendary Member
RPF PREMIUM MEMBER
To be frank you are trying to re work something into what it is not if that makes any sense.

The way that gun, looks operates, and fires is that it is basically a high pressured hand held Acetylene torch.

There is much more to be done once you have the right valve as well, it really is a complicated piece.

What you are trying to do people have tried through out the years to do and have come up empty, ymmv
 

Rob Skramstad

New Member
I completely understand and I know how the original worked.

That's exactly what I'm trying to get at, though: Can the same (or a substantially similar) effect be reproduced using the different equipment and means I've identified?

I truly don't know and couldn't find any other threads discussing this approach.

If this is a dead horse I'll happily let it lie.
 
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