A couple things about pneumatics:

1. Do we follow the FRA rules to the letter? If not what are the OZ rules regarding pneumatics?
2. I read somewhere on the internet that someone convertered an old car boot gas strut into a cheap air cylinder. Do you think it is possible & has anyone done it here in OZ? What about converting a car shock absorber?
3. Which gas would you recommend? Air would be the cheapest, any air compressor can fill the tank. What are the down sides with using air?
4. What would be a good tank, that is easiy to refill? I thought of brake resivour off a truck? What about manufacturing your own for low pressure (50psi)?

Thanks for your advice.

For people wanting to use 100psi systems, have a look at these guys. All of their push hose fittings are rated for 140psi:

http://www.automationdirect.com.au/Welcome/

They do a large range of products & even have a price list online. They deliver by courier the next day.

(I am in no way affiliated with this company, just have found them great to deal with.)

andrew from team vertex made his own gas cylinder out of a shock absorber, it seems to me like it would take a hell of a lot of work.

for tanks little fire extinguishers do the trick if you want to go full blown, but for the down to earth a mere water cooler jug (i think phil uses one?) or some fibre glassed coke bottles. they all take about 120-200psi.

use air, no one here has a dip tank to fill up with Nitrogen or CO2, so unless you want to provide your own one its HPA (high pressure air) or bust. a compressor will pump it up.

i wouldnt build a tank unless i was a qualified expert.

as for the rules none as off yet here. but use some common sense and ask the professionals.

i now nothing about pneumatics and just say all that on observation..

I use a fire extinguisher as an air tank in Marauder. I pressurise it to 200psi. It is good for the first half dozen or so flips and then the pressure is a bit ordinary.

The ram and valve came from a truck.

Co2 is readily available to anyone with an account for welding gasses, however Co2 requires a quality regulator as it is stored at extremely high pressure, then a buffer tank is usually the go. 10 bar or 145psi is the standard pressure for pnuematics and most, but not all fittings and cylinders are rated to this.
Compressed air is fairly easy to work with and can be filled by any compressor but most large compressors have a safety valve or blow off valve that opens at around 120psi, this can be a hassle if you want your tank filled to 121psi or more. Small 12v compressors range from 120pi to 300psi and a couple of roboteers use these instead.
Air tanks can be as simple as a coke bottle or an empty fire extinguisher, both would require the fitting of some type of filling point wich would inturn become the weak link in the pnuematic chain. Another option could be the use of a receiver/dryer tank from a car aircon unit but this may prove heavy as would a soda stream canister.
Cylinders or rams can be made from car shock absorbers and gas struts for bootlids and tailgates. The gas struts only have a tiny bore size and would generate less force for a given pressure than a larger cylinder and shock absorbers are heavy. Bike pumps are a better "cheap" option but I feel a purpose built cylinder is the way to go, mine cost over $100 and is rated to 10bar, it has all the propper mounting points and air fittings that are all to standard.

Hope this all helped.
_________________
Regards,
Marshal J.

Phill,

Thanks for the lead.

What did the ram do on the truck? How big/heavy is it & how long does it take to fully extend?

Also the valve was it electric or did you have to convert it from a manual one? I was thinking the valve from the air horn would work.

Cheers.

OK... I make no secrets about not being a pneumatics expert, but I'll do what I can.

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1. Do we follow the FRA rules to the letter? If not what are the OZ rules regarding pneumatics?

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quote:

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2. I read somewhere on the internet that someone convertered an old car boot gas strut into a cheap air cylinder. Do you think it is possible & has anyone done it here in OZ? What about converting a car shock absorber?

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quote:

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3. Which gas would you recommend? Air would be the cheapest, any air compressor can fill the tank. What are the down sides with using air?

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quote:

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4. What would be a good tank, that is easiy to refill? I thought of brake resivour off a truck? What about manufacturing your own for low pressure (50psi)?

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"What did the ram do on the truck? How big/heavy is it & how long does it take to fully extend?"

The ram assisted the clutch. It is 210mm with 85mm stroke. It's weight is less than 1 kg. I will weigh it in the day light hours. It extends faster than I can see.

"Also the valve was it electric or did you have to convert it from a manual one? I was thinking the valve from the air horn would work."

The valve is 24v dc. It came from the gear box of a truck. It is a 3/2 spring return type. I didn't have to modify the valve in any way. They were $20 each from Wanless Wreckers.

I don't know anything about air horns.

Thanks for the info guys.

At least I know which part of the truck to be crawling over when looking for a ram now.

i am about 3/4 of the way through modelling my robot in solidworks, Is there anyway post a *.jpg on these forums?

not yet, but there will be after the weekends event hopefully..

I'll be looking into adding some form of photo album and a few other features to the forum next week..