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Re: basic dimentions needed for gama design
Posted: Tue Sep 20, 2016 11:28 am
by Wellington
Thanks for the info Ian and Alfista. I'm looking to build an engine that does not require machining and a lot of maintainance. Do you think an epoxy piston in a steel cylinder would work without any glass?
Wellington
epoxy piston
Posted: Tue Sep 20, 2016 1:59 pm
by Alfista
Wellington, I think that you could make a close fitting, epoxy piston work in a gamma engine. It would be quite the risk in an alpha but inexpensive to replace ! 
Unfortunately, one could not expect an extended lifespan from it, but I believe that it would work with lubrication, and it could be made to a good tolerance. JB Weld makes a high heat putty. That would be my choice.
https://www.amazon.com/J-B-Weld-8297-Hi ... +high+heat
Re: basic dimentions needed for gama design
Posted: Wed Sep 21, 2016 3:53 am
by Ian S C
Go to the top of the index page, and find Boydhouse's offer of free plans, read through the Walking Beam plans, you will find how to make a piston from JB Weld.
Ian S C
Re: basic dimentions needed for gama design
Posted: Thu Sep 22, 2016 7:29 am
by Wellington
Thanks for taking the time to provide all this info guys. I'm sure it will prove useful. Q: How long can I expect glass to last inside a stainless steel piston cylinder? I have a small model stirling engine that uses a small AA size battery inserted into a brass tube and inside the brass tube forward of the hot end is a glass tube which has a glass piston (cut up syringe I guess). Q2: If glass is not an option because of its fragility will an epoxy piston in stainless steel work do you think? Hoping to get some syringes delivered today so I can get started and soon post some pics.
Wellington
Re: basic dimentions needed for gama design
Posted: Fri Sep 23, 2016 4:05 am
by Ian S C
Glass syringes should be ok for a power cylinder. When you mould the JB Weld piston, the inside of the tube that you mould it in is lightly smeared with grease, to stop it sticking, as an extra, sprinkle some graphite powder on the grease, so that the outside of the piston has some graphite for extra lubrication.
Ian S C
Re: basic dimentions needed for gama design
Posted: Sat Sep 24, 2016 11:06 am
by Wellington
Ian S C wrote:Glass syringes should be ok for a power cylinder. When you mould the JB Weld piston, the inside of the tube that you mould it in is lightly smeared with grease, to stop it sticking, as an extra, sprinkle some graphite powder on the grease, so that the outside of the piston has some graphite for extra lubrication.
Ian S C
Thanks again Ian.