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I'm starting a model loco project, live steam of course, and want to set it up with a Goodall valve. I understand the principle of how it works but am wondering if anyone has dimensions or building info. I want to make it to fit a 1/4"-40 bush. My main concern is the taper of the nozzle and valve. Any insight on this would be apprecited.

Jack
 

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The May-June 2007 issue of Steam in the Garden (No 93) has an article called a Clack-less Check Valve. It tells how to make a "Goodall" valve. I have made several and they are quite easy. The design can be modfied to fit any situation.
 

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I dont know of any other design for a goodall type valve? You need the tapered or straight hole on top for the seal to the pump bottle adapter but you also need a 1 way check on the valve which is the reason for the shaft with a drilled hole that you cover with silicone tubing. The boiler pressure seals the tubing to the shaft and seals the hole.
 

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The ones that I have bought and the ones that I have built just have a hole where you insert the hose from the squirt bottle. It is slightly smaller than the hose so that there is a press fit. The hose compresses enough to make a good seal, there is no taper in the hole. If you want I will take a couple of pictures and post them.
 

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Posted By Jack - Freshwater Models on 11/17/2008 4:49 PM
I understand the principle of how it works but the drawing appears to show a threaded connection for the pump hose fitting?
 
J


Hi Jack,
There is not thread for the pump bottle. Please note that the sheet includes two types of Goodall valves (on the left, strait on top, right angle on the bottom). The thread is used to mount the valve to the boiler. The right angle version works great for mounting on the side of a vertical boiler. I'll bug Henner to take some pictures on Saturday ;-)
 

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All mine have a taper that matches the taper on a disposable medical syringe.

They can be fed "little and often" with such a syringe, or by wedging a piece of firm but flexible plastic tube into the taper. The tube has a squeeze bottle plant spray at the other end. If you find the steam pressure too high for your syringe thumb, go DOWN a size.

I use similar syringes to top up spirit and steam oil, typically 10ml for spirit, which isn't under pressure, 5ml for water into the Goodall Valve, and 2ml for thick viscous steam oil.

David

David 1/2d
 

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Here are some pictures of a fill valve that I made. I used the existing fill plug, drilled it form the top to fit the hose on my pump bottle, drilled the bottom to insert the valve which I soldered in place with 2% silver solder.







The diameter of the portion where the little piece of tubing slips over is .110 in. I used a piece of model aircraft fuel line.
Hope this helps.
 

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Discussion Starter · #18 ·
Winn,

Interesting! Pretty much what I have seen but I usually see solid construction and filling hole on centre. Is the hole tapered? Do you just stick a plastic or silicone tube from the pump in the hole? I am planning on using a spray bottle for the water resivoir/pump.

Jack
 

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Jack, The hole is not tappered. It is off center only because in my application I thought it would be easier to access. Yes, I just stick the tube in the hole. It is a pretty tight fit and I have never had a problem with it leaking. The top of the hole does have a slight chamfer just to make it easier to insert the tube.
 
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