were would I find a small ball like valve? somthing for 1/8" inch tubing. I would like to be able to operate it with a servo. push for open pull for closed. I would like to use it as a flood valve to let water into my ballast tank and be able to close it.I can find valves here but they are all way to large, ment for 1/2 copper tubing, like what is used for plumbing. any info would be a great help. thanks and have a Merry Christmas l and a happy new year
.Dave from Saskatoon.

not sure about a ball valve, but many of the model submarine examples i've seen use a piece of fuel tubing with a "pin" pushed against it as a type of "pinch" valve...

check out post #5 on this thread:

http://www.theassociationofmodelsubm...ch-valves#1533

You could try medical stopcocks used to connect iv lines together.
http://www.utahmed.com/oemstopcocks.htm

If you prefer metal, https://us.vwr.com/store/catalog/pro...uct_id=9077586

you could put it directly over the servo to control opening and closing.

I found this....http://www.aquaticeco.com/subcategor...lve-with-Lever

Festo valves are used a lot, and they work well.

http://alshobbies.com/shop/search.ph...with+Arm+-+4mm

Most ball valves are rather stiff, as such they put quite a strain on the servo. The suggestion to pinch the 1/8 fuel line would be much easier.
If you are using a "sealed" ballast tank, ie, controlled inlet for H2O and/or controlled outlet for air, then solenoid valves might prove to be the way to go.

The snag with solenoid valves is that most of the readily available miniature versions are designed for flowing air and gases, not water. If you use them with water the internals can corrode. There are suitable solenoid valves available, but they tend to be larger. Okay on a bigger boat, but a problem on something smaller.

The Festo valves I menioned certainly aren't very stiff, and are easily turned by a standard servo. Pinch valves work well also, but it's something you will need to make yourself. Fortunately not that difficult to construct.

Originally Posted by POLARISDAVE

....... I would like to use it as a flood valve to let water into my ballast tank and be able to close it.............
.Dave from Saskatoon.

A question for you. What type of ballast tank are you using? Because my ballast tank filling is done via several holes at the bottom that are open all the time. There is no need to close them.

I use a Propel type system. When I want to blow the tank, I open the solenoid valve connected to the Propel cylinder. When I want to fill the tank with water/vent air, I open the vent valve at the top of the tank. You can buy these at Mike's Sub Works. He has a couple of choices:

http://www.mikessubworks.com/page1.html

Sounds like he's using a sealed tank water pump ballast system. You push water into the tank and compress the air inside. You can usually fill the tank about two thirds full before the pump stalls out. Therefore with this sytem you always have a part filled tank so it's important to fit baffles to slow sloshing down and upsetting the boats stability (or lack thereof!).

I guess this option would not work for him.

I wonder how Clippard solenoid valves would work in this setting. I have no experience with this type of a ballast tank.

Had some experience with Clippard valves. Fine for use with air and gas, not so good with water. The soft iron core is exposed to the water, and it corrodes cuasing blockage int he valve, they're also rather restrictive. Use a festo or pinch valve, they work much better, and are cheaper too.

As Sub Culture said, Clippard's are fine for a gas, but terrible for a liquid.
The interal ports are tiny and the flow of water would take forever.

Makes sense.

My experience has only been with gas, and no trouble with years of usage.