Well, my full pressure flipper makes sense as far as i can see, in terms or price and weight. Effectivelly you have components of the same weight in each set up, but youve also got a regulator in LP, its cost, weight, and assosciated freezing probs. Weight is especially important as there arnt that many lightweight 10bar regs around that dont cost a bomb. You can modify some, but my respect (read: fear) of pneumatics is such that I dont trust myself playing around with springs in the reg.

For my full pressure set up, Im half way through building the rams now- surprisingly not as difficult as i expected, and the O-rings were the most expensive part, but Ive been able to build my 40mm bore, 100mm stroke FP ram for about £15.

Working back, weve got the pipes and tubes and so on. Really just a question of using hydraulic instead of pneumatic, and from the bufferto the valve to the ram Im using copper pipe due to increased bore and therefore to make the most use of the G1/2 orrifice on my valve. The valve is a burket- £95 from technobots. You can pick up low pressure ones from technobots for a lot cheaper- the low pressure equivalent (ie 2/2, G1/2) is about the £45 mark iirc. Exhast valve- you could use another burket but that would be silly- very heavy, and expensive, and you dont need the operating speed. Im using a stainless 3/8 ball valve from technobots (about 5 quid) and a servo to do that. weights nothing and only cost about £10. Furthur back youve got the buffer tank- I built this agaon, but that WILL have to be certified. I would imagine that costs tho I need to talk to mario on that one. Low pressure buffertanks you either have to blag or buy or build, tho everyone seems to be able to blag them. further back youve just got your hydraulic pipe from the buffer to the tank. thats nice and simple. And of course the releif valves and gas dumps and what not, but thats all detail )

In all Id probably say FP is cheaper, potentially lighter (tho bear in mind the extra weight of the rams and buffer and so on due to greater wall thickness). But obviosly theres the draw back of getting through lots of co2 very very quickly! And the usual health warning applis: dont do it if youre not confident you can etc etc. A common sense approach to robotics will keep you safe for the rest of your life. Hmm, thats puts quite a large number of us in danger :-p