Author Topic: Strictly.... “ Hot Air “  (Read 21713 times)

Offline Chipmaster

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Re: Strictly.... “ Hot Air “
« Reply #30 on: January 10, 2018, 09:24:41 PM »
Hi Graham,
the Tesco Tuna tin is 38mm deep, if that won't do and I can't source a tin of the appropriate size then I'll fabricate a lightweight regeneratice displacer using thin brass sheet.
How are you getting on with the platform patterns? I'm confident the AJD foundry will produce sound castings  :cheers:

Andy

Offline Jo

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Re: Strictly.... “ Hot Air “
« Reply #31 on: January 11, 2018, 08:02:48 AM »
Just had a look through mine: John West & Waitrose (160g) are 37mm high and Asda is tallest at 41mm (185g)  :-\.

Jo
Usus est optimum magister

Offline Ian S C

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Re: Strictly.... “ Hot Air “
« Reply #32 on: January 11, 2018, 09:25:51 AM »
If you can't get the right size of tin can, lookout for a stainless steel container, stainless cup, mug, kitchen containers. Another way is thin walled stainless tube, with a cap TIG welded on one end to form a cup.  Steel, stainless or not is always better than brass.
Ian S C

Offline Chipmaster

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Re: Strictly.... “ Hot Air “
« Reply #33 on: January 11, 2018, 10:28:41 AM »
Hi Ian, yes I'd prefer stainless but getting it welded at a low price would be a problem for me, in the past I think you've mentioned that you have a friendly TIGer.

Jo - oooh Waitrose - posh stuff, I'll take a ruler next time we go shopping and look at a wider range of tinned food.

Searching the Internet I saw images of Sirena and John West tinned tuna 185g sold in Australia. The proportions of those tins looked much deeper than UK equivalents.

Andy

Offline Alyn Foundry

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Re: Strictly.... “ Hot Air “
« Reply #34 on: January 11, 2018, 11:20:18 AM »
Good morning, early birds.

Yes, Ian has nailed it....

A lot on non running hot air engines have used “ Cuprous “ based materials for the displacer piston. The highly thermally conductive material will equalise, very quickly the temperature differential that’s needed for these types of engine to run.

So....

ASDA sell a tinned Crabmeat,  “ Kingfisher “ I think? The tins are exactly right and light enough for the job.
The regenerative packing material is a couple of Stainless Steel pan scrubs neatly stuffed inside before soft soldering the lid back on.

I say “ neatly “ because after sealing the piston you need to carefully hold and then drill through the soldered top at 5/16” or 8 mm and then push a 2 BA clearance drill through the bottom. The final part of the job is to provide passage of the air through the regenerative material. I have inherited a set of specially ground drill bits that have a point and then two sharpened edges that neatly cut to their diameter.
I place 4 holes through the top and then rotate by 45 degrees to place the 4 holes through the bottom.

Regenerative displacer piston, finished!

Cheers Graham.

Offline Jasonb

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Re: Strictly.... “ Hot Air “
« Reply #35 on: January 11, 2018, 01:58:16 PM »
Andy why can't you silver solder a stainless one, easy to do with Tenacity No5 or HT5

Offline Zephyrin

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Re: Strictly.... “ Hot Air “
« Reply #36 on: January 11, 2018, 02:12:24 PM »
we immediately spot a hot-air engine builder  in a grocery store, he does his shopping with a caliper.

Offline Alyn Foundry

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Re: Strictly.... “ Hot Air “
« Reply #37 on: January 11, 2018, 02:24:11 PM »
we immediately spot a hot-air engine builder  in a grocery store, he does his shopping with a caliper.

Hi Zephyrin.

Indeed, I was very carefully scrutinised by a little old lady whilst measuring the various tinned fish products! She actually asked me what I was doing.

Upon providing my answer a look of total blankness appeared. It was all I could do to stop myself laughing!

Cheers Graham.

PS.  Yes Jason, a very light gauge SS tin, Silver soldered would suffice.

Offline Perry

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Re: Strictly.... “ Hot Air “
« Reply #38 on: January 11, 2018, 02:56:38 PM »
 :lolb:
we immediately spot a hot-air engine builder  in a grocery store, he does his shopping with a caliper.

Hi Zephyrin.

Indeed, I was very carefully scrutinised by a little old lady whilst measuring the various tinned fish products! She actually asked me what I was doing.

Upon providing my answer a look of total blankness appeared. It was all I could do to stop myself laughing!

Cheers Graham.

PS.  Yes Jason, a very light gauge SS tin, Silver soldered would suffice.

Offline Chipmaster

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Re: Strictly.... “ Hot Air “
« Reply #39 on: January 11, 2018, 07:09:32 PM »
Andy why can't you silver solder a stainless one, easy to do with Tenacity No5 or HT5

Yes Jason I could have a go at soldering up stainless steel but I'd have to obtain the material which might take longer than using a tin.

Meanwhile, because I don't like crab meat a friend who does is going to buy a tin of Kingfisher crab meat from Asda tomorrow and bring the empty tin over on Saturday. I've given him the dimensions.

Andy

Offline Alyn Foundry

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Re: Strictly.... “ Hot Air “
« Reply #40 on: January 12, 2018, 02:23:20 PM »
A sight unseen since 1991.


Cheers Graham.

Offline Chipmaster

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Re: Strictly.... “ Hot Air “
« Reply #41 on: January 13, 2018, 08:51:30 PM »
A Kingfisher Crabmeat tin is a close fit.
My friend brought round the empty tin this morning. it is 47mm deep as recommended by Graham and the diameter in particular the top rim is a close fit in the displacer cylinder = 3.4" bore. If I'm successful turning it into a displacer I'll bore out the cylinder to suit.
P.s. my friend enjoyed the crab meat.

WP_20180113_17_58_57_Pro by Andy, on Flickr
WP_20180113_17_57_19_Pro by Andy, on Flickr
WP_20180113_17_58_45_Pro by Andy, on Flickr

I spent the afternoon lapping the piston
WP_20180113_18_00_59_Pro by Andy, on Flickr

Andy
« Last Edit: January 13, 2018, 08:59:17 PM by Chipmaster »

Offline Jo

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Re: Strictly.... “ Hot Air “
« Reply #42 on: January 14, 2018, 09:18:59 AM »
:thinking: That tin has a draft angle on it, I thought the sides needed to be parallel if it is ok the an alternative may be to buy the tins of Salmon.

Did you notice that Graham mentioned castings to me and then he has gone quiet, not even a pic of them  :disappointed:

Jo
Usus est optimum magister

Offline Jasonb

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Re: Strictly.... “ Hot Air “
« Reply #43 on: January 14, 2018, 10:18:40 AM »
I think the angle on those spun/pressed tins is so minimal it is not worth worrying about.

It's coming along nicely Andy and is probably the only time getting crabs from a friend is welcome :-[

I wonder what size tin would suit a 24mm bore Robinson :thinking:

Offline Chipmaster

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Re: Strictly.... “ Hot Air “
« Reply #44 on: January 14, 2018, 10:56:27 AM »
Yes Jason I agree with you.....about the draft of sides of the tin, don't know about the rest  :LittleAngel:

I haven't noticed whether the tins are tapered. The displacers I made for my Rider Ericsson and Heinrici hot air engines have a clearance within the displacer cylinder so that the air can pass freely.

As for a 24mm bore Robinson perhaps a small paint tin would suit.

Jo - you might be waiting for new platforms to be cast like me. The platform on my engine is no good because of cold shuts and blow holes. Graham is repairing the patterns and we've agreed to meet up when he's ready and I'll take the patterns to the AJD foundry in Brierley Hill.

Andy