SpudFiles

Hi,

I'm planning to buy 6mm thick clear acrylic sheet, cut it into the required shapes, and glue it to some PVC pipe (5.5mm thick JIS VP- can withstand pressure) to make a piston. I will probably use either epoxy or multipurpose cement to glue them together.

Anyone got any comments to whether this is safe enough to withstand 8 bar / ~ 120psi pressure difference?

Sorry to bother you guys again with dumb questions, but I can't test it out for myself. I live in Singapore and my brother's a policeman, so I can't afford to have any exploding chambers because I can't hide them.

Thanks.

Limbeh, can you give a few more details in regards to the shapes you want to cut, i don't quite get what you mean about the piston- i think that stuff like contact cement would work for bonding the two materials but i need clarification.

edit:spllig

The piston is in the shape of a cylinder. The pipe forms the cylinder while 2 circular acrylic disks will be used for covering the 2 ends of the cylinder.

The diameter of the disks is about 4 inches / 10cm.

Thanks.

If you are using the acrylic as end plates for a piston the chamber will not be subjected to any extra stress because of the fact, how you hold the plates to the end of the piston is the problem?
I am not sure i understand your problem

Edit: A digaram would be useful

Is this a piston for use in a piston valved pneumatic? If so, the piston really isn't subjected to much pressure (although if you use a sealed hollow piece of pipe as a piston, it will have external pressure, but this isn't a real problem) Would you mind drawing up a diagram of what you want to make? Just use paint or somthing, it will help us work out exactly what you are asking.

Hi,

Here's the design.

Pretty simple actually. A simple cylinder. Only question is whether PVC can be glued to acrylic and withstand pressure difference of about 8 bars.

The inside of the piston should be hollow, unless it can't withstand the pressure difference. Which in that case I will probably just fill it up with silicon sealant.

Thanks.

The right epoxy prepared well and applied to a properly prepared (roughened and cleaned) surface will do the job.

THE EPOXY GOD HAS SPOKEN! hahahaha, but seriously, you'd be fine with your design, just don't forget the bumper!

The pressure isn't the problem, it's the bumper. As long as you have a good bumper you'll be fine.

As expected, the very mention of epoxy brought jackssmirkingrevenge out - precisely who I'm looking for.

Jacksmirkingrevenge, from your experience, do you know if marine epoxy is better than normal Araldite epoxy?

I suppose 3mm thick 75 deg rubber isn't soft enough as a bumper. I'll probably be using a lot of old mousepads instead.

Thanks!