# Solenoid Question



## coldice371

Starting a pneumatic coffin build and was looking at solenoids. Think this is too good to be true?

http://www.ebay.com/itm/DC-12V-Solen...-/250915325666

I don't need it right away so the length of delivery is fine but I'm worried about the quality of the item. Think it's worth the shot? If not any alternatives for a 5 port 4 way 12v solenoid?


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## wrasse

I have 18 of these in use and not a single issue with them. You have to know however that the threads are BSPT and not the NPT that is standard here in North America. I find it is better to purchase the fittings as well from China or the UK in 1/4 PT with a 6mm tubing end as the 1/4" tubing will fit into the 6mm end


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## coldice371

Reading the description it is npt no?


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## wrasse

The only reference that is given that I can see is Joint Pipe Bore Inlet=Outlet=1/4'', Exhaust=1/8". All of the solenoid valves fron asia are BSPT. If you look at other listing for solenoid valves from asian sellers they list it as PT. I have about 70 solenoid valves from various asian sellers ( 18 from this seller) on ebay and they are all BSPT. If you want NPT you are better off going with a North American seller, however they charge anywhere from $23 to $28 for the same valve but with NPT


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## coldice371

i bought 2....for $18 can't go wrong ill let you know what size they come in though. thanks for the heads up anyway!


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## grismcdonald

Just about to post about a cheap valve. Did you get these and how did they work?


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## grismcdonald

Coldice371,
Did you get them up and running and if so where did you get your fittings?


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## bfjou812

You can get the correct fittings from Grainger and McMaster-Carr, along with a lot of other places.They are widely available in the US you just need to know what you are looking for. Usually the spec sheet that is with the valve will have all of the information you need.


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## grismcdonald

You can get the BSPT fittings at Granger? I read a bit about being able cross over between NPT and the BSPT but did not recommend it for a pressure fitting. Any more input would be appreciated. The price of the valve is great and I have an account at granger. 

Thanks 

Gris.


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## bfjou812

Here is a link to the main page for the fittings
http://www.grainger.com/category/pu...p=CS_Product-_-PL_L1_Plumbing-_-Tube_Fittings


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## Slanks

BSP fittings are available on eBay at a fraction of the price of Grainger. I have used dozens of these solenoids without issue.

Here is a link to the 1/8" fittings. They have 1/4" fittings as well.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270624579061&ssPageName=ADME:L:OC:US:3160


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## hauntedyards

Just to round this out an store in my province deals on EBAY and they has tons of these fittings in 10 packs...

http://stores.ebay.ca/MettleAir/Pus...&submit=Search&_fsub=790434016&_sid=793583516


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## grismcdonald

Can anyone tell me how to wire this valve. I am referring to the one in the Ebay link above. There are three contacts with an LED across two of them.

Thanks

Gris


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## Hippofeet

Gris,

Is it.... this one?


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## grismcdonald

Yes Hippofeet, that's the one and that was a great tutorial. Clicking on the link, I was not expecting such a personalized instructional video. I really appreciate you taking the time to do that.

Gris


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## Hippofeet

Hey No Problemo!

I did one up for AC too, just in case, but I guess I will save that one.


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## grismcdonald

ok wired up with a 12 v 150mA Walwort and not much response. LED dim. Wired in a 12 v 1A and alot of clicking, but I have no air to it. Should the valve be moving without a load(air) on it? I am assuming that the valve may already be in the open/energized position.


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## Hippofeet

The clicking means it is working. They move fast enough (the piston inside with the seals on it) to make it difficult to view if you are clicking it on and off and looking in one of the ports. When I wire things up without air, and I hear the clicks, I usually assume all is well, and I can get set up for air.

The piston is spring-return, so the coil (this is usually, some solenoids use air pressure to assist the coil) will pull pull the piston towards the top, the top being where the coil is. Upon de-energizing, the rather weak spring, and some uber tiny air passages, will push the piston down, away from the coil.

If you take the solenoid apart, and energize the coil with the top, sprung metal piston just not quite fully inserted into the brass coil mount tube, it will suck the piston inside, and upon de-energizing, it will fire the piston a small way like a little dart, lol.

I make sceance tea boxes that way, to wirelessly knock small items off shelves, sort of a poltergeist thing.


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## Woodland Haunters

On a 2 way valve the return is by spring opposed to a 4 way which is returned by the air?? Trying to figure out if I can use these on air cylinders for props such as ground breakers or whatever.


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## Hippofeet

you know, I have never gutted a two way, except for a small 1/4 inch one, and it was the same, the energized coil pulls the piston up out of the way, allowing airflow, and the spring pushes it back down to close off airflow. I would assume (dangerous habit, there) that a larger one would be similar.

As far as 2 ways running cylinders, you could use 2, one to pressurize the cylinder, and another to allow it de-pressurize, but it would be a pain and a waste of controller channels. There just has to be a way to vent the cylinder at some point. If you really REALLY wanted to do it, I could set up a quick demo, and shoot a vid. I mean if that's what you got for valves, we can make it work, but hoo boy. Need a "Y" in line from the cylinder port, 2 valves per cylinder, and enough weight to compress the cylinder back to its starting position.

And no, on a 4 way (5 port) say it starts in position A. One port is going to be allowing airflow in that position, pressurizing one end of a 2 way (double acting) cylinder. Then the coil is energized, PULLING the piston into position B. There is also some internal venting to prevent air pressure locking the piston in place, which is what I meant and that confused things. Then the coil de-energizes, and the spring (and again, it needs to vent, if you completely tear one down you see some little [1/16th] holes here and there, those are the vents) pushes the piston back down into place in position A. While that is going on, the piston is also moving across the release ports, allowing air to flow through the system, because when air is applied to the bottom cylinder port, it needs to be released from the top or you reach a balanced air pressure where nothing moves. A one way (single acting) cylinder will have a tiny top port, to allow the air pushed up by the moving cylinder piston to escape. If a single acting cylinder is slow, despite increased tank or regulator pressure, the port may be too small to allow the air to escape at the desired speed, in which case I would drill that mofo out, and walk away with no regrets.

To further confuse things, some valves (diaphragm dump valves, and even some wacko 4 ways) are strictly air operated, with a baffling number of ports and holes and pipes and tubes and protuberances. I walk away from those, again with no regrets.

You might think, at this point, that I don't regret much. Not true. I met a girl in Hawaii once, she was a striking beauty with dark hair, long legs and a swell rack. After we talked for a while, we walked on the beach, and ended up sitting together to watch the sunset. We could hear the chatter of some folks in an open air bar behind us, and the feel of the sand on our legs where they touched was like an electric shock. I was so young. We kissed, softly, but I was too nervous to press my case. The next morning I saw her walking with some other guy. We didn't speak again, and I wasn't angry, only disappointed. In myself.

My one regret. Here's to what could have been *takes a swig of beer* aahh!


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## Woodland Haunters

Hippofeet, I thought I was confused while I was reading the first half of your response until I read the bottom part and realized what real confusion is, lol. Thanks for the response, I think I understand a little better. I don't have any of the 2 ways, just thought that was a great price and could use them on y props, but I think I'll stick with the 4 way 5 ports, seems a little easier.


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## Hippofeet

Someone else, not on the forum, brought this up today, and I had to explain it all again, and I don't think I did any better of a job. Just proves the old saying right, any idiot can make something complicated, it takes real genius to make it simple.


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