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LTD Stirling Hard to Find Materials

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Stilldrillin:

Nick.
I've got several "16mm" test tubes. From this unfinished session......    http://madmodder.net/index.php?topic=2006.0

No problem to post a few......  :thumbup:

David D

AdeV:
Nick,

I have a chunk of graphite that you're welcome to a piece of; how big is the piston supposed to be? Let me know that and I'll chop some out & send it to you.

Bogstandard:
Nick,

For a start, if you are not going to run it over an open flame like Jan does, you can just use plastic tube for the main displacer cylinder, because the lightweight piston doesn't in fact touch the sides, so doesn't need to be abrasion resistant or too critical on size. The power cylinder could easily be made from very finely bored brass, or even K&S tube. In fact you can run it over a naked flame, if you do it this way (kindly sent to me by Jan for running my eggcup Stirling with a plastic displacer cylinder).



So in fact, all you really need is a bit of graphite, which Ade has already offered you.

So we should be seeing it running by the weekend.


John

NickG:
Wow,

Thanks for all the information guys.

Dave BC, I wasn't sure how much to expect it to be but it is only a very small amount required so £6 wouldn't break the bank I suppose, will have to save that place to my favourites for future.

Chris, good point, I never really thought that the displacer one isn't really as critical so I could use almost anything, or as you and John say could even be plastic. I did find a 19mm test tube on ebay here which would do the job:

http://cgi.ebay.co.uk/BOROSILICATE-GLASS-TEST-TUBE-SIDE-ARM-150MM-X-19MM-/200542242789?pt=UK_BOI_Medical_Lab_Equipment_Lab_Supplies_ET&hash=item2eb13fc7e5


I've seen one on youtube last night that has a brass cylinder here http://www.youtube.com/watch?v=dAV_nWTwWR4 and I think the original one Jan based his on had a steel piston! I guess anodised aluminium would be good to keep the weight down and provide a scratch resistant low friction surface, I still have trouble with making a bore nice and round and parallel and a perfect finish though, unless I just bought the right sized reamer.  I didn't think the glass tubing would be that expensive but you've obviously done your research Chris.

Many thanks for the offer David, but I'm not sure whether it would work with a smaller displacer, I guess it would just need a bit more heat but it would change the ratio of swept volumes and all that you see! What do you reckon John?

Thanks Ade, that would be great. Jan just sent me the plans today, wow this thing really is Tiny - the power piston is 4.5mm dia x 5mm long!!! Don't really fancy my chances having seen it but think I'll give it a go none the less!

John, what is K&S tube? What is that you have between the flame and your displacer cylinder? I see you managed with the bent crank, Jan said he had to change his to a fabricated one.

Thanks again guys for the advice and offers.

Nick

AdeV:
Yipe, that is small.... You'd be able to make about a thousand pistons out of the hunk of graphite I've got! I'll slice off a piece tomorrow - there'll be loads more than you'll need for this job, hopefully enough that you can do other engines at a later date - PM me your address and I'll get it in the post tomorrow.  :thumbup:

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