CO2 for r/c subs?

[sgtmac1]

I bought this started 1/48th fleet boat on ebay-it has an early SubDriver in it according to my buddy, Bob Eissler. I would like to replace the pvc tank with a copper one and run co2. With the right regulators, can this be done safely? If possible, do you have any thoughts on building it? Also, looking at the size of the wtc ballast tank area, would it need to be lengthened to provide more lift to get the large top side weight up to proper trim?
Thank you,
Dave

[trout]

Dave,

Putting CO2 into copper will not be safe.

I find it very cool to see how David's technology has changed and adapted over time. I still see subtle things modified, like the way a float bottle was attached from silicon to an o-ring. I look at the photos you posted and see clever designs for the time and how it morphed to today's designs. I am sure some of the changes were for financial production reasons, but some were just better designs. Very cool.

You will love the Gato/Balao sub.
Peace,
Tom

[HardRock]

I just saw a better idea! Look at the lanyard on the rear of the motor bulkhead. That's gotta be a better way of removing those stubborn end caps - mine look like they've gone three rounds with a woodpecker, there's so many screw driver blade gouges in em. I'm off to make a lanyard (or two)

[He Who Shall Not Be Named]

Get rid of the PVC Propel on-board bottle -- a very bad materials choice on my part. I'm amazed I didn't kill anybody!

Go with copper -- but only if you use the typical hobby spray-brush 'propellant' (usually a Methane-Butane mixture); a liquefied gas that is little more than 70 PSI at room temperature. Liquefied CO2, on the other hand, is a bit over 800 PSI at room temperature. Get your CO2 plumbing wrong and that thing will take your head off!

Some old shots from my CO2 days. Note the use of the excellent single-stage Williams regulator -- developed for NASCAR pit-crews:









M

[sgtmac1]

After I change the pvc tank to copper, is there any other changes that will be necessary? Any idea how many blows that size tank can do?
Also, is Propel the only choice for ballast gas? I thought I read that someone had used propane or those small green tanks for Coleman-style lights/torches-seems that this is quite the flammable gas to be using but maybe it is safe. Menards had the small green tanks for $2.19 compared to the 40% off Hobby Lobby price of $6.75 for a can of air brush propellant today...

[redboat219]

MFR aka Manfred used butane lighter refill canisters to power his 1/72 gas torpedoes on his type 212.

[trout]

Flames and explosion comes to mind with propane, but to save propel, you can add a pump like Andy mentioned.

[redboat219]

The reason why FLAMMABLE is printed on side of a Propel can is because it contains both butane and propane.

Snort/SAS is a good alternative to gas as you don't have "consumables" that need to be replenished.

[sgtmac1]

Just started my first copper tank, held 125psi. Now, to determine attachment screws or lanyards to hold it in the wtc...

[bwi 971]

Looks good.......hope you did a hydrostatic pressure test......pressure testing stuff with air is very dangerous.

Grtz,
Bart

[trout]

The reason why FLAMMABLE is printed on side of a Propel can is because it contains both butane and propane.

Snort/SAS is a good alternative to gas as you don't have "consumables" that need to be replenished.

HAHAHAHA, I never noticed that! Thank you for pointing it out. I will stop filling by the campfire!

[He Who Shall Not Be Named]

HAHAHAHA, I never noticed that! Thank you for pointing it out. I will stop filling by the campfire!

At one very narrow bracket in my professional life, these eye-brows were not so bushy! Guess how that happened!

M

[trout]

Marshmallows by the campfire?

[sgtmac1]

I'm not sure why a hydrostatic pressure test would be used on a tank that sees pressure under 100psi that Propel provides. Certainly, these small tanks have been manufactured by the hundreds by many people w/o being subject to certification testing. For example, these tanks appear to be manufactured in a very controlled environment by someone with the knowledge and skills to create a quality product-does anyone know if they were hydrostatically tested? Isn't there an inherent level of trust that some things are safe to use? Btw, I pumped this cylinder up with air in stages, releasing the pressure, and then increasing it again until I reached the maximum of my compressor. I had previously filled it with water and found no leaks. I considered filling it with water and freezing it over night but felt that it might actually cause the tire valve(which I consider to be the weakest part of this cylinder)to fail from the relentless expansion of ice, destroying its integrity without actually being able to measure its point of failure.
You were saying about a Propel back up system? Could you diagram how that works, please?
Thank you,

[He Who Shall Not Be Named]

I'm not sure why a hydrostatic pressure test would be used on a tank that sees pressure under 100psi that Propel provides. Certainly, these small tanks have been manufactured by the hundreds by many people w/o being subject to certification testing. For example, these tanks appear to be manufactured in a very controlled environment by someone with the knowledge and skills to create a quality product-does anyone know if they were hydrostatically tested? Isn't there an inherent level of trust that some things are safe to use? Btw, I pumped this cylinder up with air in stages, releasing the pressure, and then increasing it again until I reached the maximum of my compressor. I had previously filled it with water and found no leaks. I considered filling it with water and freezing it over night but felt that it might actually cause the tire valve(which I consider to be the weakest part of this cylinder)to fail from the relentless expansion of ice, destroying its integrity without actually being able to measure its point of failure.
You were saying about a Propel back up system? Could you diagram how that works, please?
Thank you,

Those bottles pictured are for propel only. No hydro test. Just a function test (charged with propel and dunked in water, looking for leaks). That's all. The 'safety valve' on those is the flexible hose burst pressure of around 400 psi. No one's eaten a copper bottle yet.



M