# steam heat for butane tank



## Phippsburg Eric (Jan 10, 2008)

As you might have guessed I enjoy running my trains in the cold and snow. Butane...even Isobutane does not work too well in low temperatures. My scratch built Forney model does not have a water bath for the tank...that space is taken up by the radio gear. I have long thought about using steam to heat the fuel tank. 

On my Frank S which is quite a poor performer when it is cold out, even with a warm water bath. This was where I first started thinking about such a project...I never did it in all these years...Kinda hated to break into a perfectly good boiler. I had thought to use the exhaust steam...perhaps run a line back to the tender and right into the water bath.

Likewise, my Forney didn't do well this fall when it got cold. But as I built it, I felt i could mess with it. I had used Roundhouse boiler fittings and had some spares. I saw that if i took one of the hollow bolts that attaches and serves steam to the water glass, i could drill and tap a hole for an additional fitting.


I drilled and tapped one of the spares and it looked good so I proceeded to make a globe valve which would thread into it.

I had a drawing I found on line somewhere and printed out. It used British BA threads for which I had no taps, so I just used small US threads. I did find a 1/4-40 tap and die somewhere which is very useful though.

I started with a bar of Bronze for the valve body








I threaded one end to fit the roundhouse fitting.









then drilled and tapped the inside. I used two size drills, the first is the tap drill for 1/4-40 down near to the bottom of the barrel section. the second drill was 3/32" right though the threaded nipple end.









I cross drilled the barrel and made a second nipple for the line to the heater. 








I applied flux then silver soldered the nipple on. 









sorry this image is not too sharp. I machined the valve stem from 5/32" K&S stainless. It cut pretty well. I turned down each section separately so I had only a short length of thin unsupported metal. I threaded the handle end with a 1-72 thread using a die mounted in my lathe's tail stock. I then turned a 3/32" "smooth" section where I could seal the valve stem. I threaded a section 6-32 which will activate the valve. A finer thread might have been better for this application though. I then cut the part off using a tapering cut. again, a sharper taper might have been better for this valve.


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## Phippsburg Eric (Jan 10, 2008)

I guess it is better to do several shorter posts than one long one?










here is the partially assembled valve. the hex brass fitting is threaded 1/4-40 male on both ends and is drilled and tapped through 6-32. the valve stem threads into this piece from the inside before it is threaded into the valve body. the valve stem can now be run in and out by spinning it.
a brass gland nut compresses cotton/graphite packing around the valve stem to seal it...more or less.








I took out the original Roundhouse fitting and replaced it with my drilled and tapped one. then I threaded the valve into it. I added some gaskets between the valve and the fitting to seal it. You can also see the valve handle. The drawings had me drill 6 holes around it in the web so it would look more the part but I didn't do it. I did knurl it though.


I made a little fitting and gland nut to attach the 3/32" tubing which runs back to into the tender tank.









the actual heating is accomplished with a little radiator made from 1/8" copper tubing bent and soldered to a piece of copper flashing. I annealed the copper tube by heating it with my torch till it glowed briefly. I machined a 1/8" groove into a 1/2" rod. I bent the tubing in that groove. It worked pretty well but I should have made the groove deeper and the rod bigger. I had to tap on the tubing with a little hammer to get it right.


I bent a piece of 3/32" tubing to connect the valve and the radiator. I just slid it into the 1/8" tubing at the left side of my radiator until it stuck fast. I did not use any sealant as the pressure is minimal when in use.










In operation, I can just crack the valve and get a little wisp of steam from the radiator. It just vents out under the rear of the tender tank. The steam condenses in the radiator giving up its heat to the gas tank. I get a fine fire in cold weather. in the photo above you can see steam coming out from under the tender...really looks the part of steam railroading in winter!


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## xo18thfa (Jan 2, 2008)

That's a great idea. It would be interesting to stick a thermometer probe into the tank just to see what's going on. Or a pressure gauge. Big prototype engines used exhaust steam to pre-heat feed water. Could use exhaust for the gas tank too.


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## ChaoticRambo (Nov 20, 2010)

That's a very neat idea for how to keep a tank warm. My only worry would be in the summer the steam could get the tank to warm and cause the PSI to raise to dangerous levels. Figuring steam at 40-60 psi is around 290 F, and a warm water bath would be much less than that obviously. 


Might be a good idea to put a valve that you could close that steam line during the summer.


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## Phippsburg Eric (Jan 10, 2008)

That is what the Valve I made is intended to do. I can also remove a length of tubing...not soldered anyhow...which will isolate the tank in case the valve leaks or is accidentally left open. 

I cannot speak to the actual temperature or pressure but with the valve opened a bit i get summer performance out of the burner...it burns well with the gas valve cracked and roars when opened half a turn. The steam valve opened only slightly seems to be enough to do the job. I may make a more pointed "needle Valve" stem to get finer control of the steam heat.


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## ChaoticRambo (Nov 20, 2010)

Posted By Phippsburg Eric on 27 Dec 2011 05:14 PM 
That is what the Valve I made is intended to do. I can also remove a length of tubing...not soldered anyhow...which will isolate the tank in case the valve leaks or is accidentally left open. 

I cannot speak to the actual temperature or pressure but with the valve opened a bit i get summer performance out of the burner...it burns well with the gas valve cracked and roars when opened half a turn. The steam valve opened only slightly seems to be enough to do the job. I may make a more pointed "needle Valve" stem to get finer control of the steam heat. 
Ah Okay, I see now. That really is a cool idea, because I know that the water of a water bath gets cool and needs to be replaced quite quickly when it is cold out. Guess I just need to get a coal fired engine to completely get rid of the cold problem


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## Phippsburg Eric (Jan 10, 2008)

If you can keep your fingers warm as you shovel those black diamonds into the mouth of the beast! Spirit firing should be fine in the cold too...(says he who only has butane so far...)


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## ChaoticRambo (Nov 20, 2010)

Posted By Phippsburg Eric on 27 Dec 2011 06:26 PM 
If you can keep your fingers warm as you shovel those black diamonds into the mouth of the beast! Spirit firing should be fine in the cold too...(says he who only has butane so far...) 
Yes, from what I have heard, alcohol firing works fine since it is not based on pressure, and if alcohol is freezing, we got bigger problems than firing our steamers.

I too only have real experience with Butane in 45mm.


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## HMeinhold (Jan 2, 2008)

Eric,
this might also be useable to heat the cylinders for slow running. In our little engines the lowest speed is determined by condensation in the cylinders. 
Regards


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## snowshoe (Jan 2, 2008)

Nice idea. Im with you when it comes to running in the snow. I think I enjoy running in the snow more then summer running.


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## Pete Thornton (Jan 2, 2008)

because I know that the water of a water bath gets cool and needs to be replaced quite quickly when it is cold out. 
There are a few threads around here about warming your water bath in the tender using steam from the boiler - exactly as Eric does with his gas tank. 

If you don't have a water bath, then Eric's 'heater' is a great idea. There's a photo around here of ice on my gas tank on my FWRR/Ruby, formed after pouring warm water on the tank to heat it in winter. 

If you do have a water bath around the gas, then just trickle-feed the steam into the tender water bath using a valve like Eric's.


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## Phippsburg Eric (Jan 10, 2008)

I ran yesterday when some neighbors brought over their gran kids. it was very warm (for December in Maine) and i had the valve cracked open. she ran great...except when it came time to re-fuel. With the tank warmed, it is nearly impossible to get gas into it. 

I shut down the steam heat, tried re-filling a couple of times. (the kids were enjoying himself finding out where the track goes) After several attempts I did get fuel in by cracking the fuel valve as I added gas. 

The gas can is too big to but in my pants pocket to warm so It was cool (not cold)


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## Phippsburg Eric (Jan 10, 2008)

I have been running my #9 in the snow with a smile on my face this winter. We have had a little snow...not too much and I have been able to keep the line cleared. I have found that a little shot from the steam heater is plenty to keep the gas flowing. I do not need to keep the valve open most of the time. I just open it a bit to heat things up and leave it just cracked a little for a minute or two to get a nice fire roaring away. 

Here we are at the new Quebec station. 











After the run I open the valve to drop the pressure in the boiler...makes a nice plume of steam!


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## Charles (Jan 2, 2008)

We started doing this with globe valves steam connects a while ago, works well in the cool/cold water.


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