Clack Valves

[Ron HancockParticipant @ronhancock63652]

Hi does any one else have problems with clack valves.

I have bought 6 in total but cant get any that seal.

I have tried putting an air line on to check with the other end in water leak past like a sieve.

I have 5 = 1/4 and one's and 1+ 3/16 air passes through all of them.

When on the Loco as steam gets up water passes back into the Tender.

I have made sure the arrow pointing in the right direction of flow.

I have tried tapping the ball in two of them with a Brass rod but still wont seal.

Blowing with my mouth they seem to be sealing can all these be foulty or is it the way i am testing them.

Ron

[Ron HancockParticipant @ronhancock63652]

[Ron HancockParticipant @ronhancock63652]

[Ron HancockParticipant @ronhancock63652]

Posted by Ron Hancock on 14/09/2016 18:48:13:

The other two are still on Loco just could not be bothered to take of so frustrating all are commercial ones and fitted vertical to make sure ball sits on seat and fitted correctly with arrow pointing in direction of flow to boiler.

[not done it yetParticipant @notdoneityet]

My 2'' clack not works reasonably on my water pump.

On a more serious note, have you tried lapping the seat of any of these? The job should only take about 5 minutes after making the tool, either with one of the balls or a new (possibly more superior) one.

[Jeff DaymanParticipant @jeffdayman43397]

Hi Ron,

Just a couple of out of the box ideas.

1. can you reduce the amount of check valves in the water feed system, down to one at each feed point of water to boiler?

2. I read that you have tried re-seating the balls with a hammer. This often works but not if the seat machining is bad to begin with or has become corroded, or if balls are not round or are corroded. You could try measuring the balls with a micrometer to be sure they are not more than a thou or two off spherical. For check valves the balls must be pretty round and have a smooth uncorroded surface. These days with rafts of balls and other hardware coming in from overseas there is lots of off-size parts around- even when bought as high-precision!

If the balls are corroded or are not round within a thou or two I'd say they are not fit for purpose and you should speak to the supplier about a credit or exchange. You might be able to get higher precision balls from simplybearings.co.uk or other drive parts suppliers.

You could check the seat with one of your measured, now known-spherical balls. Colour one up with a felt pen and load it in the check valve. Rotate with a short piece of rubber hose or a wood dowel with some sticky tape or putty on it. Then remove the ball and with a magnifying glass examine the seat. If it does not have an even ring of ink on it with no gaps, then it will probably leak, and needs to be dressed. If it does you could do it by machining with a D bit or lap it in with some automotive valve grinding paste on a ball. If you use the paste method don't re-use the ball used for grinding, if it is scuffed up, in the finished valve. Use a known good one.

3. If there is room in the valve you could try making a metal poppet type check valve with an o-ring to seal it, an a spring to close it, rather than a ball. Be sure to use Viton o-rings if you do this approach.

4. You could try a Viton rubber ball rather than stainless balls. I have heard of rubber balls disappearing into pipework under high pressure or vacuum though, so I would not recommend that as a first try approach.

Hope these ideas help. JD

[Ron HancockParticipant @ronhancock63652]

Posted by not done it yet on 14/09/2016 19:12:06:

My 2'' clack not works reasonably on my water pump.

On a more serious note, have you tried lapping the seat of any of these? The job should only take about 5 minutes after making the tool, either with one of the balls or a new (possibly more superior) one.

No as new did not lap in not sure how to unless i weld a ball to the end of a Rod and use fine grinding paste but it is a thought Thank you

[Ron HancockParticipant @ronhancock63652]

Posted by Jeff Dayman on 14/09/2016 19:24:23:

Hi Ron,

Just a couple of out of the box ideas.

1. can you reduce the amount of check valves in the water feed system, down to one at each feed point of water to boiler?

2. I read that you have tried re-seating the balls with a hammer. This often works but not if the seat machining is bad to begin with or has become corroded, or if balls are not round or are corroded. You could try measuring the balls with a micrometer to be sure they are not more than a thou or two off spherical. For check valves the balls must be pretty round and have a smooth uncorroded surface. These days with rafts of balls and other hardware coming in from overseas there is lots of off-size parts around- even when bought as high-precision!

If the balls are corroded or are not round within a thou or two I'd say they are not fit for purpose and you should speak to the supplier about a credit or exchange. You might be able to get higher precision balls from simplybearings.co.uk or other drive parts suppliers.

You could check the seat with one of your measured, now known-spherical balls. Colour one up with a felt pen and load it in the check valve. Rotate with a short piece of rubber hose or a wood dowel with some sticky tape or putty on it. Then remove the ball and with a magnifying glass examine the seat. If it does not have an even ring of ink on it with no gaps, then it will probably leak, and needs to be dressed. If it does you could do it by machining with a D bit or lap it in with some automotive valve grinding paste on a ball. If you use the paste method don't re-use the ball used for grinding, if it is scuffed up, in the finished valve. Use a known good one.

3. If there is room in the valve you could try making a metal poppet type check valve with an o-ring to seal it, an a spring to close it, rather than a ball. Be sure to use Viton o-rings if you do this approach.

4. You could try a Viton rubber ball rather than stainless balls. I have heard of rubber balls disappearing into pipework under high pressure or vacuum though, so I would not recommend that as a first try approach.

Hope these ideas help. JD

Hi thank you for your suggestions none of the balls are correded as all Clacks brand new as its a new build.

I think i will have to make some thing with a ball on the end and try lapping in but so frustrating as all new comercial ones.

Ron

[Ron HancockParticipant @ronhancock63652]

[Ron HancockParticipant @ronhancock63652]

Posted by Ron Hancock on 15/09/2016 19:43:34:

Hi had several messages asking for Photo of the Pipe work hope this shows it ok.

i have disconnected the axle pump just going to run Injector and hand pump.

Julian is helping me by sorting my Clacks so might soon be running .

Thanks for all suggestions very much sappreciated

Ron

[Bodger BrianParticipant @bodgerbrian]

Posted by Ron Hancock on 14/09/2016 18:47:20:

I have 5 = 1/4 and one's and 1+ 3/16 air passes through all of them.

Could some kind soul translate for me please?

Thanks – Brian

[JasonBModerator @jasonb]

He has Five clacks for 1/4" pipe and one for 3/16" pipe and all pass air in the wrong direction

[Ron HancockParticipant @ronhancock63652]

Thank you Jason flipping steam engines thank goodness we have Guys like Julian Atkins in model engineering. He is going to sort my new Clacks out for me so they seal what a tremendous effort Guy.

Sure once these seal the Loco will be able to Run at last.

Ron

[Ron HancockParticipant @ronhancock63652]

Well folks had some great news today I heard from Julian who is looking at my clack vales and he has found that they are leaking. So now I know what the problem was I know how to fix. Julian has very kindly offered to re seat the Clacks properly for me but I am still so surprised so many commercial Clacks that are leaking so badly. The only two I have not leaking where from black gates I have sent Julian5 to look at I have 4 more here two working two leaking badly. Hopefully as soon as Julian gets chance I can fit with confidence and enjoy running at last.

Massive big thank you to Julian

Ron

[Bodger BrianParticipant @bodgerbrian]

Posted by JasonB on 15/09/2016 20:54:20:

He has Five clacks for 1/4" pipe and one for 3/16" pipe and all pass air in the wrong direction

Thanks Jason – I sort of suspected that was what the figures meant but I didn't want to assume..

Brian

[julian atkinsParticipant @julianatkins58923]

I dont think it would be fair to disclose too many gripes, but of the 4 commercial check valves Ron sent me all 4 leaked.

I've made countless check valves over the years. I dont think there is any magic in making them seal perfectly, just good engineering and machining practice.

Ron's commercial inline valves were 3 of 1/4 ball, and 1 of 3/16" ball he sent me.

The seats of the 1/4 ball type were badly made with the hole not reamed plus a chamfer on the seat. I took a whisker off each seat in the lathe, then reamed the holes. I used a hardened steel ball bearing to biff the seats with a proper drift then the stainless balls were replaced with precision ceramic balls. I also altered the other end which was a straight slot to 2 slots at 90 degrees and altered the lift which was rather constipated. All burrs were removed which wasnt the case originally. 2 or 3 of the originals had machining swarf that would easily have caused the balls not to seat, and another had thread sealent that was generously applied gumming up the works.

All 4 tested on my compressor and sealed perfectly.

I've seen some horrors over the years of commercial fittings particularly injectors. These were not badly made, just badly finished.

They are back in the post to Ron tomorrow hopefully.

Cheers,

Julian

[julian atkinsParticipant @julianatkins58923]

Incidentally, Ron was apparently quoted £200 by one guy to sort out these check valves. I do these sort of jobs free to help out fellow miniature loco builders, and do the same for problem injectors.

It annoys me when guys like Ron buy stuff in good faith from reputable model engineering suppliers and the stuff turns out to be faulty.

Cheers,

Julian

[not done it yetParticipant @notdoneityet]

Might country of origin (manufacture) and a lack of quality control (both by manufacturer and vendor) have a lot to do with shoddy goods? I do notice that many items produced in China are imported in bulk, then simply sold on at a well elevated price….

I once worked for a well known company that sourced many electonic parts from China. Any 'out of spec' goods were simply returned – the whole lot, not just the faulty ones!. The suppliers were then much more careful, and did not send shoddy products. They were still tested for conformity on arrival. Testing was cheaper than unit failures later (most likely after installation).

[Ron HancockParticipant @ronhancock63652]

I agree so much extra work for a novice I have lost several months trying to find the problem if it was not for people like Julian I would still have been buying more Clacks trying to get them to work. The trouble I had I thought it was my work wrong spent so much time trying to sort out. You would think the suppliers would check them before selling on save them the problem. I am just so pleased to be getting mine back knowing that they will work nice to have confidence in them.

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