Stirlingengineforum.com

Hi List,
Thanks Daryl for setting this forum up especialy for tincan engine enthusiasts.
I'd like to pass on my experience of the use of concrete in my engines.
I started out using silicone to seal and to make my displacers and displacer cylinders because of the lack of equipment in my shed.
I have always needed to re-invent the wheel so I didnt follow anyones plans for my first engine. It took three rebuilds before I managed to get it to work. I only managed to demonstrate it about three times before I cooked it. It was from my frustration at having to virtualy start from scratch after every breakdown that I decided to make an engine that I could take apart and modify easily.
I now make my displacer cyinders in two parts ( hot end , cold end ) I have made up a reusable mold to cast a flange on the open end of two cans with dowels to ensure correct location and bolt holes to enable quick assembly. Silicone is still used as a gasket material but by oiling one of the surfaces before assembly the ends come apart easily when required.
If this is usefull to other builders I will post photos etc on request.
The system also gives better performance to the engine by providing a signifcant barrier to the exchange of heat between the ends.
regards
Terry

I like the idea of a two part displacer to minimize conduction of heat between the two sections. I keep wishing for a durable material to use that approximates the cylinders on LTD gamma and the Pringles can metronome.
Needed is a material that won't burn or melt and has poor heat conduction.

I've been considering making various engine parts out of a mixture of perlite and waterglass (sodium silicate) often used as a DIY furnace cement. This should, I think, be both lightweight and heatproof. There are several YouTube videos on how to make this cement. I've had several styrofoam displacers warp or melt.

For example: https://m.youtube.com/watch?v=jnNnoEKyrC4

You can make the displacer directly with panels of ceramic fiber. It's stiff and light weight, and easy to work.

terrence thompson wrote:Hi List,
Thanks Daryl for setting ............
Terry

I had thought of this myself and have considered putting a layer of fire cement on the hot end of the displacer with a thin alum disc embedded in it to reflect some of the radiant heat.
Wellington

mastrovetraio wrote:You can make the displacer directly with panels of ceramic fiber. It's stiff and light weight, and easy to work.

I see some online sources for ceramic fiber of various types/brands/compositions

Ebay, Etsy... some appears to be flexible (comes in rolls).

Also, is it permeable ? Could air get through it ?

I was also interested in making the engine body (displacer chamber) out of some kind of ceramic or cement. Of course that would need to be air tight.

Hi Tom. Ceramic fiber come also in rigid panels. Airtight, but can not afford pressure. Ceramic fiber panels come in a variety of density in front of a variety of temperature to withstand. I've maded kiln to work up to 900° C with C.F. 5 cm thick and you can put hour hand over, was barely warm with the hell i side. Absolutely insulator, I think the best material for a displacer.