AA 410 Fill Connections

[leadbottom]

OK didn't expect to have to ask this basic a question :  (

But I filled my used 410 ERB for the first time the other day.  Used a 80cf scuba tank with a Sherwood valve and this cheapie yoke from Pyramyd:  http://www.pyramydair.com/cgi-bin/accessory.pl?accessory_id=534

I was able to fill the gun, but did run into problem with small leaks so sort of had to fiddle with it to get it filled correctly.  The problem is there's a small leak at where the AA fill attachment connects to the fill host.  There's no washer or O ring there.  Should there be?  I'll try some teflon tape on the threads next time, but not sure if that'll seal the rotating nut joint.

And there might be some air leaking at the connection between the gun and the fill attachment/connector.  Both fill O rings on the gun look to be in good shape.  And the brass fill attachment had an O ring inside that I don't think came from AA, more of a workaround I think to stop the leak.  It was sitting at the bottom of the brass connector.  I took it off because it was causing the connector to rub too tightly against the "T" piece that holds it to the gun and so was shaving a bit of brass off the contact area.  Anyone run into this before?  I'm going to try a tiny bit of silicone base grease on it next time to help the seal.

Because of these tine leaks during the fill, I had to fill by quick bursts of air, and wasn't able to get a good reading on the fill yoke's gauge.  I read from the gun's gauge by waiting for it to stabilize between the small bursts of air.  I know the correct way to fill is open the valve slowly until air starts going into the gun, but it seemed I had to open the valve a lot before air would get in the gun and at that point it would go in way too fast, hence my filling it with small bursts.   I was careful to keep the bursts small and the reservoir never even got warm, and it didn't take long to go from 12 bars to 18 bars.

[jon]

I use the white pipe thread tape, it works everytime I put it on all the threads of my whole set-up..  Put it on thick and tighten til you cant tighten anymore.  You'll also learn how to fill slowly, scuba tank knobs were never made to be finely adjusted.  I find that my catalina tanks is very touchy but my luxfer is very easy to turn in small increments.

[johncedarhill]

I know this may sound strange but make sure that the threads are a match. I bought a foster from a vendor who insisted that the threaded foster matched the thread on the whip. Visually it was not even close enough to consider taping it which the vendor suggested I do. As I recall some of the fittings are 1/8 british pipe which is a fine thread. My fittings did not reguire any taping which is not to say that taping is wrong. Sometimes these fittings just don't match up as easily as they should (in my opinion).

[leadbottom]

Thanks John and Jon.  The thread does seem to match well on my fitting, so I'll try teflon tape on mine.  I noticed the guy on YouTube showing how he fills also has tape at the joints.  He actually seemed to have some tape at the top of the gun's fill fitting, a bit of loose end can be seen while he was removing the fill attachment, but not clear enough to see exactly how he had it on there.  But it does seem he too has some sort of leak at the top like I seem to have. Not a problem though, more a minor nuisance.

[kirby999]

The threads on the fill probe for AirArms are 1/8 British strait threads , but as Jon said a few layers of Teflon tape will stop the leak at any connections to the 1/8 USA FPT . I use the tape at all my connections unless there an O-ring at the junction ; to ensure a tight fit. I added a male foster fitting to my AA probe and a female foster to the end of my hose . This allows me to attach the probe to the rifle first , then attach the fosters together and reverse for removal. This makes it easier IMO to fill. I also have another fitting, a 1/8 brass coupling with a 1/8 plug at one end and a male foster on the other . With this I can attach to my hose , open my tank's valve and read on the gauge how much air is left in the tank. And if you have multiple PCP's with a different style probe, you can just make up a fill probe for that particular model with a male foster and switch easily using the same hose and gauge clamp for all your guns. kirby

[leadbottom]

Thanks for the information David.  I'll have to see if I can find a hydraulics shop around here who carry some of these fittings so I can save on shipping costs.  I bought a 1/8" plug at Lowes but it turned out to have NPT threads and I read somewhere it's not safe to mix threads on high pressure connections.

[johncedarhill]

In my limited experience the best assortment and reasonable prices on fittings was from Airhog. There are also metal reinforced "o" rings available. Call me chicken but I never feel comfortable with mixing threads.