# Suction Fan for Live Steam



## artgibson (Jan 2, 2008)

What alternative suction fan device is available , other than the Aster. Just curious because I think the C62 needs more early draft. Would appreciate any advice.


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## Semper Vaporo (Jan 2, 2008)

I use a small air source (battery powered air compressor) and a "venturi" made from a set of two brass tubes, one that fits neatly in the chimney (3/8-in.?) and another smaller one (1/8-in.) that is in a hole drilled crosswise to the first. The small one then has a small hole drilled in the side the middle of what is inside the bigger tube. The larger one is set down into the chimney such that the small hole in the smaller tube is aimed "up". An air supply is appled to one end of the small tube (the other end is crimped or plugged) so that air is directed out the small hole and up the larger tube. 

This exiting air is traveling faster than the other air and as such is of less density. It then creates a vacuum in the large tube which draws air from the smoke box and thus through the flues and over the fire (the draft).

The disadvantages are that the small air compressor is noisy and one more thing to carry to the track. I have tried several other air sources and found that even a small "swimming pool play toy" inflator will work and is lots quieter, but again it is another thing to carry to the track and was lots harder to figure out how to get it adapted to the hose to the venturi.

Personally, I think the Aster type fan is more compact than anything I have been able to build, having the batteries attached as part of the whole thing. 

I did lots of experiments trying to measure the air flow that was necessary to provide the "correct" draft and found that just about any draft was good enough for an alcohol fire, but I do not have access to a coal burner to know if what I have done is good enough for that... I have been told that coal firing requires more initial draft.


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## Semper Vaporo (Jan 2, 2008)

I also should point out some other possibilities:

I used to just apply compressed air to the boiler via the water inlet (clack) valve and then use the built-in blower. I had an "air pig" (small 5 gal. tank) that I would fill at the gas station to about 125psi.

NOTE! IF you do this! DO NOT apply the air unless two conditions are met! 

ONE) be sure the blower valve is open FIRST, and 

TWO) apply the air through a small restriction (narrow tube, 1/8-in or less) so the air flow is severely restricted and cannot rapidly over presurize the boiler... it will probably handle 125 psi without bursting, but the pressure guage and other attachments might not fair too well at that pressure! 

If when using this method you keep the blower valve open then the pressure will have a hard time rising to unwanted levels and the restricted airflow into the boiler will give you more time to get it disconnected if you notice your pressure guage headed toward "bending the needle" or going around the second time!

With the air pig I had I could start the fire at least twice before I ran out of air and had to go refill it.

If you have good arms you could use a bicycle pump to supply the air source to either the boiler or the venturi I explained in the previous post.

I have tried plastic fans but the exhaust from the fire melts the blades. Same for putting one of the plastic air toy inflators placed in the chimney! It can "toast" them real quick! (Or is that "par broiled"?)

I also used a 1.5-inch computer CPU fan for several years before I went to the venturi. I managed to find a very hard plastic fan (they are all plastic!) that had the motor fairly well sheilded from the hot and wet exhaust and these fans sometimes have to handle very high temperatures in a computer. I took a small sheet of brass that was about twice the size of the fan. I then bent the sheet such as to be a cube with the fan as one side. I sealed the fan to the box with silicone caulking and put a hole in the opposite side from the fan and installed a tube that would fit into the chimney. For power I bought a 8 AA battery holder from Radio Shack to provide 12 Volts for the fan.

The first one I made lasted at least 3 or 4 years before I began to hear a ticking sound. I cut the caulking away to get to the underside of the fan and found that although it was high temperature plastic it had begun to deform and had some thin strings of plastic sticking out from the ends of the blades. I purchased another fan with the identical part number from the same place (again Radio Shack) but it had been redesigned such that the motor was not nearly so well shielded from the wet environment and it lasted through about 2 startups and then didn't work anymore at all. I tried other CPU and computer case fans but none worked as well or lasted as long as that first one.

Ideally the motor needs to be outside of the flow of air to keep the moisture away, but most CPU fans are not made that way. Also, it needs to have a metal impeller (blades) so it won't melt in the heat!


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## RimfireJim (Mar 25, 2009)

Posted By Semper Vaporo on 30 Jul 2009 02:28 PM 


TWO) apply the air through a small restriction (narrow tube, 1/8-in or less) so the air flow is severely restricted and cannot rapidly over presurize the boiler... it will probably handle 125 psi without bursting, but the pressure guage and other attachments might not fair too well at that pressure! 

If when using this method you keep the blower valve open then the pressure will have a hard time rising to unwanted levels and the restricted airflow into the boiler will give you more time to get it disconnected if you notice your pressure guage headed toward "bending the needle" or going around the second time!


Rather than running that risk, why not just spend a few buck more and add a regulator with a gauge to the air tank, and set it just below the safety valve setting? Then you can use it for an air brush!


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## David Leech (Dec 9, 2008)

Dear Gibs,
There is also the Accucraft suction fan.
I can't say that I have paid much attention as to whether it is, or sounds, more powerful.
I have certainly seen people with an extra battery wired into their Aster fans to get a little more draft.
All the best,
David Leech, Delta, Canada


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## artgibson (Jan 2, 2008)

Any idea how the extra batteries are attached. 
Art Gibson


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## JEFF RUNGE (Jan 2, 2008)

Art, the early Aster fans ran off 3 batteries. They were not mounted directly on the fan like what is sold today. I see them on ebay from time to time. I have found fresh good quality batteries help increase draft.


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## artgibson (Jan 2, 2008)

Now Jeff
Are trying to say that I am too cheap to use new fresh batteries. He He as you would say. Just thought I would start a thread that would generate some discussion and that I might learn something.
The Aster fan works great with the S-2 . She ran great the last time we steamed her up.


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## xo18thfa (Jan 2, 2008)

Saw somewhere a guy using a set-up almost exactly like C.T. showed, except he used a 1 gallon garden spray tank for the air source.


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## Steve Shyvers (Jan 2, 2008)

Bob, 

That's what I use for an alcohol-fired loco. I fitted the garden sprayer with a pressure gauge for reference and a regulator for the air out. It works well for alcohol but probably is not powerful enough for a coal fire. I have to pump up the garden sprayer every couple of minutes, and 10 psig is about the maximum pressure I can get it to. Not sure I'd have the stamina to use it to raise a coal fire, athough the venturi gizmo would work with a compressor. An alternative would be to connect a "steam donor" loco to the venturi and use steam instead of compressed air. 

Steam


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## David Leech (Dec 9, 2008)

Posted By gibs035 on 30 Jul 2009 05:17 PM 
Any idea how the extra batteries are attached. 
Art Gibson

Hi Art,
I recall someone with the extra battery just taped to the top of the existing batteries on the Aster suction fan.
Not sure how he added the wires.
Maybe we need a 'deluxe' fan system with speed control?
All the best,
David Leech, Delta, Canada


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## Dave -- Use Coal (Feb 19, 2008)

John Shawe makes a fan, it is what Bill Courtright uses. You might talk to Bill about his battery lash up. He has rechargable batteries he uses from a pack wired to the blower. I have a John Shawe fan as my back up and it is still a virgin. I have found the Aster fan to work well in all three of my coal fired engines. 

If you want to contact John Shawe let me know and I will give you his phone number. John is not real good about answering email. And --- I suggest you talk to Bill first and maybe try his fan and take a look at his electrical lash up.


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## Steamboil (May 12, 2009)

I like the Accucraft Fan the best, for it seems to have more power than the Aster version. 

Happy steaming, 
Tom S.


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## xo18thfa (Jan 2, 2008)

Posted By Steve Shyvers on 30 Jul 2009 10:23 PM 
Bob, 

That's what I use for an alcohol-fired loco. I fitted the garden sprayer with a pressure gauge for reference and a regulator for the air out. It works well for alcohol but probably is not powerful enough for a coal fire. I have to pump up the garden sprayer every couple of minutes, and 10 psig is about the maximum pressure I can get it to. Not sure I'd have the stamina to use it to raise a coal fire, athough the venturi gizmo would work with a compressor. An alternative would be to connect a "steam donor" loco to the venturi and use steam instead of compressed air. 

Steam 

Hi Steve: You may have been the one I recall. It's a great idea. The UK "oldtimers" used bicycle pumps, that would have been real work


Bob


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## main131 (Jan 3, 2008)

Posted By gibs035 on 30 Jul 2009 06:48 PM 
Now Jeff
Are trying to say that I am too cheap to use new fresh batteries. He He as you would say. Just thought I would start a thread that would generate some discussion and that I might learn something.
The Aster fan works great with the S-2 . She ran great the last time we steamed her up.
I find exactly the oposite with my S2. My aster fan lacked the suction to pull the flames forward sufficiently when I steamed the engine last Thursday. I had evidence of flames 'around' the firebox and some dripping onto the hosts track. I borrowed John Squires 6 volt blower to solve the problem.
It seems to me that the Aster is fine with smaller boilers. IE typical British outline, but you need a more energenic pull with a lot of the bigger and longer American boilers.
On my coal fired stuff I wouldn't even attempt to use the Aster, you can wait for ever. I sometimes go up to 12v!
In 10 years of coal firing I have never seen anyone using an Aster blower in our Society although I admit that it is mostly G3


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## artgibson (Jan 2, 2008)

Like Jeff said though, withfresh btteries theS=2works fine with e Aster suction fan. what suction fan do you use withthe 12v power. I would like to know because I am just about to buy the Accucraft.
I am not adept enought to try the Venuturi. although it looks pretty interesting.


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## zephyra (Jan 2, 2008)

Posted By main131 on 02 Aug 2009 03:16 PM 
Posted By gibs035 on 30 Jul 2009 06:48 PM 
Now Jeff
Are trying to say that I am too cheap to use new fresh batteries. He He as you would say. Just thought I would start a thread that would generate some discussion and that I might learn something.
The Aster fan works great with the S-2 . She ran great the last time we steamed her up.
I find exactly the oposite with my S2. My aster fan lacked the suction to pull the flames forward sufficiently when I steamed the engine last Thursday. I had evidence of flames 'around' the firebox and some dripping onto the hosts track. I borrowed John Squires 6 volt blower to solve the problem.
It seems to me that the Aster is fine with smaller boilers. IE typical British outline, but you need a more energenic pull with a lot of the bigger and longer American boilers.
On my coal fired stuff I wouldn't even attempt to use the Aster, you can wait for ever. I sometimes go up to 12v!
In 10 years of coal firing I have never seen anyone using an Aster blower in our Society although I admit that it is mostly G3


I've never had a problem with the Aster fan and the larger US locos. The key is to ensure the smoke box is well sealed - the first Aster kit I built (Duchess) seemd very difficult to fire until I reassembled the smokebox and did a better job to make it air tight. Since then, I've been careful and never had an issue even on the biggest boilers such as the Allegheny. Don't know about coal - I've never tried it!

Robert


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## main131 (Jan 3, 2008)

Posted By gibs035 on 02 Aug 2009 03:36 PM 
Like Jeff said though, withfresh btteries theS=2works fine with e Aster suction fan. what suction fan do you use withthe 12v power. I would like to know because I am just about to buy the Accucraft.
I am not adept enought to try the Venuturi. although it looks pretty interesting. 
The 12v 'blower' is the one we use for G3 coal fired. Mine was made by a member of the Society which is pretty basic. It incorporates a small 12v motor which I attach to a recharchable 12v battery with clips.
You can really feel the suction on this as you can imagine. I suppose the Aster one feels a bit 'limp' by comparison.
Don't get me wrong, I still use the Aster, but as I say, not on coal fired


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## David_DK (Oct 24, 2008)

Hi Art 

I know that you are looking for alternatives, and this probably looks like the one mentioned earlier. Anyway the design is a bit different. 
look at: http://web.mac.com/anders.grassman/iWeb/Topsida/T&inflator_suction_device.html 
Regards 
David


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## artgibson (Jan 2, 2008)

Well David
I went to Ace hardware and bought what looks like what the above reply has in it, I have put it together and am charging my small portable air pump and will give it a try tommorow at Steamin at Steve's".
I plan on taking my test track to fire it up on so we can check the JohnsonBar linkage and really see how long I can keep her running. Looks like a pretty straightforward gizmo that mightjust work.
As I have said before"We shall see".


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## Jack - Freshwater Models (Feb 17, 2008)

Suction fans are pretty simple to build and there is a plan for one in the G1MRA's "Projet " book.


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## artgibson (Jan 2, 2008)

My pump did not charge up last nite. I think the rechargable battery is shot. I will get aother pump and see how it works.


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## artgibson (Jan 2, 2008)

Got my new Slime tire inflator to use with my "Venturi" and the other draft device I made for my Aster C62. I hooked them up to he little compressor which weighs just over a pound andcan produce 300 psi
if needed, just to see what kind of draft it will make and seems to work very well._ will put it to a test next Tuesday if it does no rain._


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## David_DK (Oct 24, 2008)

Nice to hear 

Looking forward heering your findings. 
I use a normal aster vent (old school type) but I forgot to tell that I made a "speed control" years ago, so it runs with 1,5 or 3 or 4,5 volt. Normally I newer uses 4,5 but It sounds like I might need it in the future. 

What type of coal are you using now? Charcoal, Antracite, "energy bricks" ? (the last one - made from oli - are very popular here in DK, but im quite unsure if they are good to use since they reach a temperature of 1300 celcius. 

Regards 

David


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## artgibson (Jan 2, 2008)

Using hardwood charcoal to start with and then add Welsh coal. I hope to video steaming up next week, using the new devices to see how they work and will show the coal we are using here.
I have to cut mine up smaller though.


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