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LOOK AT THIS! Here is an image I should share for newer Stirling builders at least.

From my first running stirling, and after putting it under what I thought was too much heat for the design I was utterly amazed at the lack or deterioration to the displacer. Internal temperature is apparently nowhere near what the exterior is. The paint from the aluminum can(displacer) holding the steel wool is not even tarnished! The steel wool shows some blueish discoloration yet the aluminum strip holding the steel wool in place at the bottom(I believe was only epoxied in place) is not even damaged. I knew the aluminum wouldnt take much direct heat so I did use a tin can for the bottom, the 1/4 inch void was filled with steel wool then high temp silicone applied to seal it. Using a mirco torch to heat the engine I brought it to near red hot(sometimes spots of red hot). These little torches can produce some extreme heat, enough to solder and even weld thin metals so it was much more than an alcohol flame would have been. Yet this design and materials used can definitely endure higher temps. Good news to me.
The mirco torch and heat applied can be seen in this video:
https://www.youtube.com/watch?v=5TycrOca7sk

The temperature of the aluminium can should not start to make the paint go brown, after it does, it will collapse, even aerosol cans just fold up.
With steel the colours act as an accurate thermometer, ranging from pale straw/yellowish at 230*C, to blue at 300*C. Ian S C

Ian S C wrote:With steel the colours act as an accurate thermometer, ranging from pale straw/yellowish at 230*C, to blue at 300*C. Ian S C

Your experience and willingness to share is priceless!

I thought this video would add to inspirations for water cooling designs.
http://www.youtube.com/watch?v=pPrRRm08UrM

Hawke,

Thanks for the photo. Good stuff.

A suggestion?

Make an extension for your heat stack and make the outlet slightly smaller than your current opening. Make a sort of very shallow funnel. As the hot exhaust rises it will lose some of that heat and contract a little. A slight length/height extension will increase "draw", and pull more air to the flame, and that slight constriction in the exhaust at the terminal end should limit too much heat from being pulled out of the flame box. Imagine the expansion chamber used on 2 stroke motorcycle engines. That " snake swallowed a watermelon" look has a purpose.

Keep up the great work!

R

very good R, wiil do. Thx

ANother cooling design. Looks like a thermosyphon
http://www.youtube.com/watch?v=d-cXmokLOFQ

PS:Got the expansion chamber Vent Tube made theropod.
Put in a piston replacing the diaphragm for a test. Heavy copper so less power overall.

That engine could be made much more efficient, by using a water jacket instead of the coil of tube, a larger water tank, and an out board bearing on the crankshaft would reduce friction greatly.
With a thermosyphon system the top pipe(hot) must be below the surface of the water in the tank. If a pump is used the top tube can be clear of the water in the tank, and gain an advantage in cooling by the water falling through the air in droplet form. Ian S C