Some questions about making LPE's

[technicboi]

Hi forum,

I want to make some single/double cylinder LPEs, and I need to find the correct oil to purchase to lubricate the cylinders and the switches, so I have a couple of questions about both.

First, I chose a silicone oil that is safe on rubber and plastic, but is the o-rings/seals on the pneumatic cylinders rubber or silicone? I know that silicone oil can make silicone o-rings and seals expand, so I wanted to make sure it will be ok.

My other question is is it required to cut the friction tabs on the Pneumatic switches (I only have the newest switches) or could I just put oil in the switch?

My previous non-modified engine was really terrible and didn’t really work, so that’s why I'm looking to make another one. 

Thanks!

[nerdsforprez]

On 5/25/2023 at 12:38 PM, technicboi said:

Hi forum,

I want to make some single/double cylinder LPEs, and I need to find the correct oil to purchase to lubricate the cylinders and the switches, so I have a couple of questions about both.

First, I chose a silicone oil that is safe on rubber and plastic, but is the o-rings/seals on the pneumatic cylinders rubber or silicone? I know that silicone oil can make silicone o-rings and seals expand, so I wanted to make sure it will be ok.

My other question is is it required to cut the friction tabs on the Pneumatic switches (I only have the newest switches) or could I just put oil in the switch?

My previous non-modified engine was really terrible and didn’t really work, so that’s why I'm looking to make another one. 

Thanks!

I do not believe you can make a good LPE without the frictionless switches.  I have tried and like you, only achieved minimal success.  Now, I have not used the new switches, only the old, but they are just too rigid to work effectively.  I also think you need to drill the holes in the pneumatic cylinders larger as well.  

I have an LPE from Alex Zorko and it works great.  Had it for around a decade now.  I know you can buy the frictionless switches, if they are too much of a problem to build.  They can be expensive to experiment on, sometimes, unless you have experience converting them, it is actually cheaper to just buy them.  

[TechnicRCRacer]

Someone told me to use silicone oil in pneumatics to make them work smoother, but I never had success with it because they kept sticking. If you want an oil that is essentially the same, ISO 68 hydraulic oil is a close match (I use it as lathe way oil as well). Maybe a lighter-weight hydraulic oil would be the way to go.

[Gray Gear]

I have seen some LPE designs that don't use the switches at all, but control the airflow by squeezing the pneumatic hoze. It seemed to work very well.