High strength high temp rated non conductive materials

rppearso

Does anyone know of any good materials to make pipe out of that can withstand around 200 psig, 250 F and is completely non conductive? Would also be nice if it was durable to external bumps and drops as well. Was thinking carbon fiber but that wont handle high temperature.

ChaseRLewis73

Those specs aren't that high, your looking for either a 'high temp' polymer like teflon (they don't melt until 350-450F typically) or a ceramic.
You can also just use normal pipe with an insulating wrap depending on your need. That would probably be cheapest. Next step is teflon coated pipe then after that reinforced hightemp polymer hose.

Have to know more info to give better idea.

rppearso

It absolutly can not be a conductor, I am going to run different experements with varoius gases at high temperatures using electricity.

Is the polymer hose ridgid or can it be made rigid? Do they make high pressure ceramic piping? Is ceramic durable?

ChaseRLewis73

High temp and gas is a problem for polymers if your going to be vaporizing organics. You'd be restricted to PTFE hose and all ptfe hose has steel wire mesh reinforcement. Electric field could pose problem though, I'd check with manufacturer and ask what they think. It would for sure keep you safe from any internal current but I'm not sure how it would effect the life of the hose.

Hose isn't 'rigid' but working with the stuff myself I can tell you it isn't easy to move so semi-rigid is a good way to describe it. As in the **** is MAD heavy for it's size and while flexible it most definitely takes work to move it. You can use zip ties to latch it and short of someone hacking at it with an axe you'd be ok. Also it not being rigid means it can be guided to be more out of the way which is actually a benefit.

Ceramics aren't fragile if made for construction. Quartz or some glass is the other alternative and what is used in most lab equipment designed for high voltage gases. You'd need to talk to the manufactuerer about sealants though alumina paste sealant (cheap and ceramic compatible to 3000 Celsius) is what I used the 1 time I did ceramic tubing and it worked fine. But if you use alumina paste it isn't coming apart without breaking. Quartz if thick enough should handle 250 psi easily.

If neither of those work your only left with alumina which overspecs your setup by an order of magnitude. But is really pricey. But next to diamond and nanotubes you don't get stronger. Diamond coated carbide bits break on contact when trying to machine this stuff.

rppearso

Thank you for the help, I will get online and start contacting alumina, ceramics and quartz manufacturers, I already found a quartz manufacturer and they just need a design and specs from me. I had no idea quartz could withstand 250 psig, quartz would be my first choice but I had believed it was extremely frigile and could not handle any pressure to speak of.

I could probably flange the ends with A spec gaskets but I would have to make sure the glass could take the strain tightening bolts down.

Enthalpy

PTFE would be very bad because it creeps horribly, even a moderate stress and room temperature.

Many plastics would perform properly at +120°C and that little pressure. Don't overkill because heat resistance is what makes plastics expensive - and they can be VERY expensive. Have a look at Matweb and Goodfellow for instance, or better, at plastic manufacturers.

One other solution is just glass. Some chemistry labs still have a craftsman capable of manufacturing any shape - or choose among existing hardware, for instance at a chemistry provider, as you'll probably find an acceptable shape among the many existing ones. With some wall thickness, 17b is easy to withstand.

Carbon fibres conduct electricity. Glass fibres would not but their resin isn't very inert and may react with you gas.

rppearso

What about ceramic material such as this http://www.tech-ceramics.co.uk/Tube&pipe.htm

Enthalpy

Nothing against, except things like fused silica cost an awful lot... It's made from selected quartz crystals, you know?

The cheap ceramic is glass (together with porcelain and a few more).

rppearso

I dont mind the cost (unless its $500 a foot for 3" or 4" pipe or something really crazy like that), otherwise it just has to work. I plan on doing experements with high pressure high voltage lasers so I dont need alot of it, it also looks like it would be easier to flange together than glass or quartz.

Enthalpy

If you want to avoid contamination, which may well be the case for gas lasers, fused silica may be better, as it is cleaner than glass. But watch the cost!

rppearso

Was that link I posted "fused silica"?