Man with limited tools needs help!

[timayers]

Hi all,

I have built a couple of LTD stirling engines, my first was in school many years back for my final design technology project (I got an A* for it!!) and more recently a small solar powered engine. You can see this one on youtube:
http://www.youtube.com/watch?v=qU48ckoUuLc

I am in the planning stage for my next engine, a slightly larger non-rotary solar powered stirling engine. My problem is that I no longer have access to a lathe and large scale machines to make pistons and displacer rings. My new project will no doubt use a diaphragm as I did with my last project but I need help with sourcing well machined acrylic to make the displacer cylinder.

My design is a little odd and uses 3 or 4 rectangular displacers - they stand almost vertically and will "rock" on a pivot at the bottom. I want to build the walls of the displacer with clear perspex, 35mm wide, 10mm thick. I need a total length of about 2.5m, but I am happy to cut it to length and then glue/screw it together.

Does anyone have any suggestions on where to get such machined perspex (or perspex displacer rings and ready made cyclinder/pistons)?

Sorry I don't have a CAD design at this stage, I haven't finalised anything yet, I just want to know I can get the parts first.

Thanks,

Tim.

[Cartech]

I've used http://www.airpot.com for piston&cylinder sets they offer. About 20.00 US Dollars but worth it. As for tubular Plexiglas, the best prices on that stuff seems to be Ebay. Suppliers always have min orders that go way above what I can justify. I have a couple engine designs in my head and on paper I'm waiting for reasonably priced materials to build. Scrap metals used to be easy to find but everyone recycles that stuff now and new materials often have to be bought in large sizes or bulk.

[timayers]

Thanks Cartech,

I have tracked down a UK supplier for Airpot and asked for a quote. I agree, it is difficult to get hold of scraps these days but Ebay has all the raw materials I could ever need (at a price). My main problem is the lack of machinery to turn a 1m length of acrylic tubing into 35mm rings or cut acrylic sheet into accurate strips.

Tim

[Cartech]

A table saw can do a pretty good job as will a chop saw. Follow up with a sandpaper block or even a belt sander. I've had to make do with what I have as well. A drill press is the only truely useful Stirling "tool" I own. One day I hope to get a small 3 in 1 or hobby lathe.

[timayers]

Sadly the only power tools I have access to are a soldering iron and a 19V battery drill! I have tried using a tenon/wood saw but it's just not precise enough over relatively large work.

I am looking at the possibility of using the casing from a 12v 120mm computer fan for a displacer cylinder. After cutting out the fan bit and filling in some gaps, it's a good size and flat top and bottom. Has anyone else tried using fan casings for LTD engines?