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Author Topic: A few steam questions  (Read 722 times)

derekwarner

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Re: A few steam questions
« Reply #25 on: May 27, 2020, 12:02:26 AM »

belli......You will find Citric Acid at more competitive price/quantity from Home Brew stores  O0 ..... Derek

[You may need to increase the concentration above the recommended value]


https://nationalhomebrew.com.au/wine/national-home-brew-citric-acid-100g


'For acid bathing of copper and ceramic saddles, dissolve 5g in one litre of cold water and soak for 24 hours'
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Derek Warner

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Illawarra Live Steamers Co-op
Australia
www.ils.org.au

Jerry C

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Re: A few steam questions
« Reply #26 on: May 27, 2020, 05:34:16 AM »

When I made my first boiler I ordered a kilo of citric acid. Got a funny look off the postman.
Jerry.

frazer heslop

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Re: A few steam questions
« Reply #27 on: May 27, 2020, 03:15:32 PM »

I used to buy Scalecleen by the stone from the States its a form of citric acid and works far better. Check the spelling not my strong point.

No luxury digi thingy ma bobs this end just a ciggy paper and count the turns :} .I used to make a living fixing tool makers oops moments and they always blame the machine but the fault codes never lie %) 
cheers
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frazer heslop

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Re: A few steam questions
« Reply #28 on: May 27, 2020, 08:03:51 PM »

This is a small wobbler I made for a 12inch Puffer.
Its still waiting for the hull
Have you seen Les Propers Youtube he has some nice small boats and steam plants
https://www.youtube.com/watch?v=9rcorLIJVdU
https://www.youtube.com/watch?v=EURne7s7u-8
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belli

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Re: A few steam questions
« Reply #29 on: May 27, 2020, 10:15:59 PM »

I mailed Leslie to get a copy of his book but regrettably wasn't able to.  I do like his little boats but they might be a trifle small for me, shaping the hulls would also be a bit time consuming and quite difficult to get symmetrical if you were impatient like me.  I think if vac-formed or molded hulls were available, that would be better for me.

I also have the building of Clyde puffer on the list, they were really what I found first and the French Mini-Vap 50's.  I have the Boxer Clyde Puffer in CAD, ready for laserin' but haven't got to it.  It might make a suitable hull for a simple steam plant as it could be built in a few hours if you had all the material to hand.  There is a nice read here: https://www.modelboats.co.uk/news/article/puffin/525     of a fellow that did exactly that.  It wouldn't take long to put something  like that together.


I did buy JohnTom's Clyde Puffer in CAD and was terribly disappointed.   I work with CAD a lot and what I received really was of no value.  Taking some images that you have found on-line, feeding them thru a photo to CAD converter really doesn't cut the mustard. 


Regrettably things at work are starting to tick upwards, I will be busy for the next two weeks but will endeavour to spent a little time finishing off some engines and making a start on some boilers.  My favourite non-ferrous supplier will be re-opening on Monday, they do allow me to go and pick through the off-cuts.  You still pay 'full' price but at least I can get smaller pieces.  The flywheels of these three engines were machined from 11/2" hex bar as that is what I had....

Keep building Frazer, more photos and sketches please.

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frazer heslop

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Re: A few steam questions
« Reply #30 on: May 27, 2020, 10:56:20 PM »

There is some drawings on the net for a Clyde Puffer named Vital Spark I think this is what Les based his boat on
Good luck with the engines
cheers
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belli

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Re: A few steam questions
« Reply #31 on: Yesterday at 04:05:10 PM »

OK, today's haul:
Ten pints (about 5l) of battery acid, $9.
Plastic bucket (I'll be careful) with a lid, $2.50.
Silicon O-rings, 6x1mm (8mmOD) $1.72/100. 

Silicon O-rings, 9x1.5mm (12mmOD) $2.00/100. 

They couldn't find the 3x1mm...  All other sizes are available, minimum order is $15 per size (about 700 O-rings), six weeks delivery.
623, 624 and 625 Bearings $0.55 each.

Most of the designs I have seen for small steam engines recommend O-rings but offer no suggestion of sizes, Frazer?

Now, back to the salt mine   <:(

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frazer heslop

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Re: A few steam questions
« Reply #32 on: Yesterday at 10:23:42 PM »

Most of my engines are Imperial the smaller have a 0.070 cross section the larger .103
Silicone O rings are for static applications from memory but they are what I use and just bung a new one in when needed
Groove sizes on this site not the cheapest but I dont want several hundred
With O rings fitted you will need a lubricator as they dont like to run just on wet steam
The 3mm are they for the piston rod seal if so just make a standard packing gland and use ptfe tape it will make little difference
https://www.glrkennions.co.uk/silicone-o-rings.html
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belli

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Re: A few steam questions
« Reply #33 on: Yesterday at 10:39:10 PM »

Those sections are much heavier than I thought, 1.7mm - > 2.6mm  My thinking was that on such small pistons, 8-10mm, 2mm section would be simply too large.  I'll call tomorrow and see what they have.

Correct, the 3mm was for the piston rod, never thought to try PTFE tape.   I do have some graphited/grease/yarn kinda packing, quite large, about 1/4" diameter, was going to try pull it to pieces and make a seal from that.  I did also buy some 1/8" square graphited yarn for the Stuart 10 pistons.

I try to machine the pistons to fit the bore but never quite seem to manage a good fit.  Tried lapping with polishing compound, making a new piston, trying again, etc.  They just never seem quite right.  Maybe the fits are good but I just don't know what a good fit is.   I'm hoping with the O-ring I can machine the piston slightly under size and the O-ring will provide the fit.   Most of my bores are honed with a Sunnen machine at a friends place but the smaller hones are missing their stones.  I guess I'll get some stones ordered soon.

Thanks,


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frazer heslop

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Re: A few steam questions
« Reply #34 on: Yesterday at 10:49:35 PM »

I also unpick a strand from 1/4 packing either works OK for me
A thou clearance on the piston is my target for steam engines Hot air engines are a different matter on these I have made some external laps to size the pistons
Dont make the ring grooves undersize as it will become a problem as the engine goes over BDC or TDC it will bind a wee bit of wiggle room is better
The more important thing is the piston is concentric to the piston rod as is the bottom cover and packing gland .This is why I use the glue chuck as my kit is simply not accurate enough to just use a collet
Probably telling my Granny how to suck eggs
cheers
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derekwarner

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Re: A few steam questions
« Reply #35 on: Today at 12:50:46 AM »

belli.....3 x 1 o-rings


3 x 1 o-rings ...[9-020 or 6-018] are non preferred sizes and may be available in 70 Shore NBR which is not suitable for our modest steam pressures


[/size]2.9 X 1.78 [1-006] is probably the closest generally available in FPM or Silicon to suit a 3 diameter shaft Silicone is listed as ~~ 70 Shore A and is recommended as for static applications FPM [Viton] is listed as ~~75 Shore A so is more suited to dynamic [piston or rod gland] applicationsAs frazer notes...picking smaller strands of graphited cotton yarn [J Walker Packings] is absolutely suitable :-))  for both piston and gland, although may need a little preload to attain the first steam pressurization


Derek
[/font]
[/size]Derek



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Derek Warner

Honorary Secretary [Retired]
Illawarra Live Steamers Co-op
Australia
www.ils.org.au
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