Pneumatic Weapon

[mmarab]

Hi,

Great site and Forum, really good knowledge.

My understanding of Pneumatics is pretty basic, but as part of my project to build a decent weapon for a heavy weight i thought i would prototype it first. I'm looking to build a forceful spike type weapon.
So to increase my knowledge I have purchased a few basic bits:

1) 16mm Bore 100mm Stroke 1.0Mpa Pneumatic Cylinder
-> Amazon Link

2) DC 12V 2 Position 5 Way G1/8" Outlet Pneumatic Electromagnetic Solenoid Valve
-> Amazon Link

3) Pneumatic Quick Fitting 6mm to 6mm Push In Speed Controller
-> Amazon Link

4) 49.2Ft 6mm x 4mm Pneumatic Air Hose
-> Amazon Link

5) 10 Pcs 1/8" PT Male Thread 6mm Push In Joint
-> Amazon Link

Now, from videos and articles i have looked at, i'm hoping these components will work together and get this working on a small scale and increase my understanding.

My questions:

1) Based on what i have purchased, does it seem like a viable small scale solution?

2) Regarding the compressed co2 to power this, what should i be buying? I've struggled in this area understanding what i need to buy.

3) Any recommended websites for purchasing Pneumatic parts?

Thanks for your time in advance, any help would be much appreciated.

Marcel

[maddox10]

For playing and learning, the parts you bought will help you in a steep learning curve.

These parts are ment for 3 to 10 bar compressed air from a standard compressor.

But the questions.

1) the parts ain't up to the task in any weightclass. Too heavy and large for beetles, not strong enough for any heavier weightclass.

2) CO2 is a fickle beast and you'll need at least some practical experience with people who do know the stuff.

3) Most of the Robots using pneumatics use custom build or at least heavely customized parts.

Have a look here.

[mmarab]

Thanks for the response, much appreciated.

My parts have arrived, i have put them together, just need to work out the co2 part now. I have a company locally that deal in pneumatics, so i'm hoping they can give me some pointers. Hopefully after this I'll have a better idea as to what i'll be needing

[maddox10]

I hope they are knowledgable about the nature of CO2.

[emisnug]

Now, I'm new to robotics, but I'm familiar with CO2 and HPA systems. I'd stay away from CO2 if I were you - as maddox says, it's a fickle thing. Your output pressure can change by ~150psi just by tilting the cylinder if you've got a big one.

I would recommend that you do your testing with a High Pressure Air (HPA) system or a small compressor. You can pick up new .08l/3000PSI bottles for around £40, and you can go to your local paintball site or scuba center to fill it. You can also get regulators for the HPA bottle fairly easily - although I'd stay away from Ebay ones for the time being, they tend to be fairly unbalanced with an output pressure of 800PSI - far more than what your parts can handle.

[maddox10]

There isn't a lot of choise actualy if you're building a machine that will be competitive.

The rules state that the maximum pneumatic pressure in the robot, anywere, is 1000psi/68bar max.

A typical heavyweight will use 1 2kg aluminium fire-extinguisers as main storage bottle.

That bottle contains 1024L of CO2 gas(if expanded to 1 bar)

The same size of bottle filled with 68 bar of compressed air will contain 200 liters of air.

Pity, as HPA bottles filled to 4500psi will contain 90% of the gas as a CO2 filled bottle.
And will avoid the problems associated with CO2.

[emisnug]

Yeah, but having been unfortunate enough to see a 1.5L/4500 tank delaminate at 4000PSI, I can totally see why they're not allowed!

[mmarab]

Thanks for the input Robert.

I don't want to sound cheeky, but I was wondering if you could provide some links to sites for an example a HPA system, small compressor and a regulator that you would consider useful. I'm currently looking around it's quite difficult making some decision, not that I would buy anything straight away but it would mean i would have something to think about and know I would be looking at the right things.

Some examples:

HPA - link

Compressor - Link

Regulator - Link

[maddox10]

The bottle you show is a paintball bottle. WAY to small for a heavy. And as the rules don't allow 3000psi gas pressure in the machines, not suitable.

The compressor is a toy. Good for an airmatress at the beach, and maybe re-inflate a not to flat car tyre in the field

The regulator is a low pressure one. Feed that anything over 20 bar, and you get a self disconstructing piece of kit.

[J.Y.F.]

As another newbie here, was going to start a new thread, but found this one. Hope that's OK.

Maddox, i saw you recently sold some Burkerts and mention cheap chinese copies. But searches result in bucket loads.

What should we be looking for. Is there a specific model that is suited to HW demands? 30 character part Nºs aren't exactly self explanitory to the less initiated. Or are they?

Regs say valves/regulators will be tested prior to events, so, Is there a list for approved components on the CO2 trail? is there a reference for FRA acceptable parts?

[maddox10]

Bucketloads of copies of the Burkert, but most state 35 or 40 bar of working pressure.
I tested a few of those, and had a lot of failures on the function. The solenoids are not good enough.
Also the brazed solenoïd stem is a way weaker part than the stamped stainless steel stem Burkert provides

I found a supplier trough Alibaba that is willing to supply versions rated at the same working pressure as the Original, and they use a silver brazing for the stem. Fot the intent and purpose, that is the same valve.

There isn't a "FRA approved parts list", nor for pnematics, nor for hydraulics.

Test check on the event itself is done by people that have years of experience (even if they look young) and those will spot shoddy work or iffy practices and will tell the owner/user that.

[J.Y.F.]

Thanx for clearing that up. Figured you always get what you pay for, especially in this field.

Never any question as to the competence of those that do the checks at the events, just the wish to access all the info to be able compete and keep on the right side of the line.

so which Burkert(or other make) Solenoid Valve is best suited for the job? Or, Got a part Nº for a Burkert or at Alibaba?

[maddox10]

The Burkert everybody favors is the Burkert 5404 with 24V DC solenoid.

[J.Y.F.]

Cheers, that's one on the list ticked.

Only a few hundred others on the list to sort out, now.

Thanx

[maddox10]

I have forgotten a bit of information. Only the 1/2bsp version can handle the pressure.
And then the coil likes a bit more voltage than 24. Most of us just feed it 36V.