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From Kits/Castings / Re: Strictly.... Hot Air
« Last post by Alyn Foundry on Today at 01:22:30 PM »
Something is missing  :noidea:


Hi Jo.

What a " dark horse " you are! That's excellent progress.   :ThumbsUp:

It saddens me that you're going to have to wait until next month for the platform casting.

I noticed that you have even split the big ends on the connecting rods, I used to " dummy " those!   :LittleDevil:  As Jason has mentioned perhaps a coat of primer wouldn't go amiss?

Cheers Graham.
Boilers / Re: My first Boiler build
« Last post by MJM460 on Today at 12:47:48 PM »
Hi chucketn, you asked about the inside radius of the curvature between the flanges and the flat ends.  The codes I have seen specify a minimum of one times plate thickness, but bigger is better if it does not interfere with any bushes for fittings, like a level gauge in the ends.  However, for a boiler with no provision for making up water for continuous running, a level gauge is an unnecessary complication.

Similarly a flange overlap of three thicknesses is acceptable of the flange is visible for inspection - I believe this means on the inside, so you can check for full penetration of the solder, otherwise four thicknesses.  So probably sensible to aim for four.

You can face the flanges in or out, but facing in is slightly stronger for internal pressure, at least for dished ends.  For a flat end with longitudinal stays there is probably less difference.


Boilers / Re: My first Boiler build
« Last post by chucketn on Today at 12:32:35 PM »
Thanks for the comments, Harry. I have a piece of 5/4 oak that I will make the former from. I'm going to use a hole saw to cut several circles of oak and glue the stack together.
Chatterbox / Re: Talking Thermodynamics
« Last post by MJM460 on Today at 12:30:49 PM »
Hi Willy, I have always wondered if the food calorie matched the thermal calorie.  Remember that in heat units, one calorie is the heat required to realise one gram of water through one degree C at the standard temperature.  This results in one calorie equal to approximately 4.182 Joule.  Similarly, one BTU is about 1055 J.  I have only quoted approximate conversions, as the exact definitions require too many decimal places.

However, I read recently that there is a factor of two between food calories and thermal calories.  Possibly to allow for the energy involved in digestion of the food, but I don't know how the food calorie is defined, so don't quote me on that.

So if we know the draw bar pull of the locomotive and the distance, we know how much work was done, and work is a form of energy.  But we would need to do some tests to determine the efficiency of energy conversion from the food bars to the draw bar work.  The second law of thermodynamics says some of the energy in the fuel must be lost in the conversion.

Weather forecasting is a bit out of my league, but I understand that the availability of large supercomputers and large quantities of real time data, has allowed meteorologists to develop some amazingly good models to solve the equations of mass and heat transfer for the atmosphere.  But there is some variability, and racing ocean sailors compare the output of several different models and additionally, look out the window in order to decide what route to sail through the weather.  The model we use to check the weather for outdoor activities tells us the wind for every hour over a week, and it is usually close enough for the first day and usually only subject to relatively minor changes for the ones after that.  But the models predict not only wind but also temperature and moisture content, and even the point at which rain occurs.

Hi Chris, your meter should be possible with inputs of drawbar pull and distance, but it would require lots of sampling the Snickers to confirm the conversion efficiency for accurate calibration.  You would not want to delegate that responsibility to the elves!

Hi Jo, yet another definition.  I think it would take more than a snicker to get me through a Marathon, but you may have explained why I never finished a marathon, I thought I could stop after 26!  I obviously never looked at the fine print.

Thanks everyone for following along,


From Kits/Castings / Re: Strictly.... Hot Air
« Last post by Jasonb on Today at 11:31:18 AM »
Just ordered a metre of 3mm at the vast sum of 1.13 delivered :)

Feels like you just got your woodburner done just in time, we had our first frost this morning :(
Vehicles & Models / Re: Chris's Marion 91 Steam Shovel
« Last post by MJM460 on Today at 11:21:34 AM »
I was thinking about driving those things.

A drag race from the lights would not be very exciting, but you would always have right of way!

Looking forward to learning about beat cutting, you have quite a pile of blanks there.

From Kits/Castings / Re: Strictly.... Hot Air
« Last post by Jo on Today at 11:08:04 AM »
Yes that is the rope gasket.

That is the 6mm diameter version, I was fitting the larger version to my log burner yesterday before I started cremating the brown stuff  >:D

From Kits/Castings / Re: Strictly.... Hot Air
« Last post by Jasonb on Today at 10:58:50 AM »
Something is missing  :noidea:

Paint :LittleDevil:

Coming along well, is that the heat resistant gasket I can see under the tin can? I need to sort a thinner version for mine which did get some paint on it yesterday :)
From Kits/Castings / Re: Strictly.... Hot Air
« Last post by Jo on Today at 10:36:03 AM »
Something is missing  :noidea:

Chatterbox / Re: Talking Thermodynamics
« Last post by Jo on Today at 09:27:09 AM »
We need a gauge calibrated in Snickers per mile...

I thought there are 26.2 miles in a Marathon or as they call them the other side of the pond a "Snicker"  :facepalm:

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