DIY Epoxy Kitt graphite coated piston

Discussion on Stirling or "hot air" engines (all types)
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Coco Mbella
Posts: 8
Joined: Fri Dec 21, 2012 11:42 am
Location: Germany

DIY Epoxy Kitt graphite coated piston

Post by Coco Mbella » Sun Apr 07, 2013 1:44 am

Hi there,
After a lot of experimenting with different materials for a Stirling Engine power piston, this is the best result i came up with. A piston made out of Epoxy Kitt and coated with griphite. The piston is really light, airtight and needs no lubricaton due to the graphite. Furthermore, the Epoxy Kitt is able to resist temperatures up to 300°C and ist easy to machine.
The epoxy kitt is from the manufacturer BOLDT & Co. OHG - Turbocoll 2000.
Here some more technical data of the stuff.

hardening: < 5 Min.
fully hardening: < 60 Min.
temperature: max. - 40°C / + 300°C
hardness: max. 80 D
compressive strength: max. 500 kg/qcm
elongation: max. 5%



Greetings from germany
Coco

Hopper
Posts: 54
Joined: Fri Feb 08, 2013 6:54 pm

Re: DIY Epoxy Kitt graphite coated piston

Post by Hopper » Sun Apr 07, 2013 2:15 am

Neat.
Any details of your production process?
Is the epoxy cast and then machined to final size and shape?
How do you get the graphite to stick to the epoxy? Or do you just spray it on the finished piston then intsal into cylinder?

I really like the video of your engine disassembly too. Very nice work indeed.

But what is the Cameroon connection?

Coco Mbella
Posts: 8
Joined: Fri Dec 21, 2012 11:42 am
Location: Germany

Re: DIY Epoxy Kitt graphite coated piston

Post by Coco Mbella » Sun Apr 07, 2013 3:08 am

Hi Hopper,
I am actually working on a DIY Stirling Engine tutorial, but the production process of the piston is more or less the same as that of bladeattilas.

The only difference is i use precision mechanics oil instead of vegetable oil and reduced some of the piston weight. Yes, the graphite is just sprayed on the finished piston and forced through the piston chamber. After moving the piston a few times, the graphite gives the piston a shining, tight and plain surface where it touches the piston chamber.
I am half Cameroonian and half German and i build the engine mainly to inspire a friend of mine in Cameroon, who builds 700W wind turbines using simple materials and tools.
Greetings Coco

Hopper
Posts: 54
Joined: Fri Feb 08, 2013 6:54 pm

Re: DIY Epoxy Kitt graphite coated piston

Post by Hopper » Sun Apr 07, 2013 7:04 pm

That's cool. Thanks for the tip. And the wind turbines too. I have heard of guys making them out of washing machine motors. I think they are probably the way for cheap energy in developing countries. Stirling engines have potential too, but there is already enough problems with deforestation without adding to it.

Keep us posted on your Stirling development. I find it very interesting.

Chriske
Posts: 87
Joined: Sat Oct 02, 2010 1:24 am

Re: DIY Epoxy Kitt graphite coated piston

Post by Chriske » Mon Apr 08, 2013 12:43 am

Hi,

I have lots of experience using resin(molding).
Maybe, just maybe resin will do the job to. I'll try it one of these days...!

Thanks,

Chris
Mijn thuis is waar mijn draaibank staat...

Coco Mbella
Posts: 8
Joined: Fri Dec 21, 2012 11:42 am
Location: Germany

Re: DIY Epoxy Kitt graphite coated piston

Post by Coco Mbella » Mon Apr 08, 2013 11:02 pm

Chriske wrote:Hi,

I have lots of experience using resin(molding).
Maybe, just maybe resin will do the job to. I'll try it one of these days...!

Thanks,

Chris
I think It will work out all right with resin. :wink:

Ian S C
Posts: 2221
Joined: Thu Dec 02, 2010 5:15 am
Location: New Zealand

Re: DIY Epoxy Kitt graphite coated piston

Post by Ian S C » Tue Apr 09, 2013 1:11 am

I found (a few yrs back) a piston designed by someone called Dan Haigh, its cast in a bit of copper tube, and made with JB Weld which is ok to 600*F. He coated the inside of the tube with grease to aid removal, I wonder if you mixed graphite powder in the grease (good thick layer). A bit of metal with a transverse hole to attach the con rod is cast into the piston. Ian S C

fullofhotair
Posts: 265
Joined: Sun Aug 05, 2012 6:28 am

Re: DIY Epoxy Kitt graphite coated piston

Post by fullofhotair » Mon May 13, 2013 9:43 am

I first impregnated the outside of the jb weld with graphite powder. I used a soft graphite pencil. The harder the pencil lead the more clay there is in it ,not good. I also totally impregnated a small piece of jb weld to form the seal around the connecting rod on the displacer.

Coco Mbella
Posts: 8
Joined: Fri Dec 21, 2012 11:42 am
Location: Germany

Re: DIY Epoxy Kitt graphite coated piston

Post by Coco Mbella » Mon May 13, 2013 6:19 pm

Ian S C wrote:I found (a few yrs back) a piston designed by someone called Dan Haigh, its cast in a bit of copper tube, and made with JB Weld which is ok to 600*F. He coated the inside of the tube with grease to aid removal, I wonder if you mixed graphite powder in the grease (good thick layer). A bit of metal with a transverse hole to attach the con rod is cast into the piston. Ian S C
hi ian,
i did not mix the graphite powder in the grease, the graphite powder is just sprayed on the finished piston. to reduce weight i did not add a transverse. i just hope the epoxy kitt is strong enough. 600°F = 300°C maybe the same material!?
coco

Coco Mbella
Posts: 8
Joined: Fri Dec 21, 2012 11:42 am
Location: Germany

Re: DIY Epoxy Kitt graphite coated piston

Post by Coco Mbella » Tue Jun 04, 2013 3:25 am

finally the piston in action ;)

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