Friday, May 13, 2016

US Divers Second Stage.....The Metal Years

In 1970 US Divers introduced their new second stage (listed at part #1085 in most service manuals)
This simple, tough and reliable stage would serve them well and is still found on the Conshelf XIV today. 
It was used on all regulators in their line for years with only the sticker on the purge button being different. Internally they are pretty much the same with minor variances to the demand lever. The service procedures for them is found in the manuals along with the first stage they accompany.  This is the fixed blade knife of second stages. It will work with just about any manufactures first stage and can handle intermediate pressures from 110 to 160 psi with no modifications. Have one of these serviced and ready to go in your bag and if your latest and greatest gee gaw fails at the dive site you can attach one of these and go diving without missing a beat. 
In the 1970 catalog it is shown with an unusual angular exhaust T which I have seen very few of. Next came the exhaust T in the picture above which worked great but the compound it was made from went from flexible to concrete in a very short time and about the only way to remove one was to cut it off with a knife.  An updated exhaust T is available which is lower profile and appears to be manufactured from silicone which should remain flexible long after we are gone. 
Servicing the stage is straightforward and over the years I have seen dozens of approaches to doing it all with varying degrees of success.  
You need the ability to hold the poppet still weather you adjust by holding the poppet steady and turn the nut or vise versa.

 Below are a variety of tools that accomplish this. 
Next you will need something to either hold the nut steady or to turn it with.

You will get varying opinions on setting lever height....Manual says one thread from contacting the demand lever. Others say it's good when three threads are exposed past the nut. One thing is certain, once you have the lever height set it's not going to move on it's own.  
Often divers with a slight hiss or leak due to low pressure seat wear on their second stage will simply depress the purge button while unscrewing the volcano orifice, flip the low pressure seat over, re assemble and go back to diving. Not saying this is the proper service technique but it speaks to how resilient and reliable these second stages are.  
One area to look at closely when servicing is the snap ring that retains the purge button. From my observation they seem to rust and corrode faster than other parts on the stage and should be replaced. No one wants their purge button to spring off their regulator while underwater...

Main diaphragms rarely need replacing an usually respond with a good soap and water cleanup. 
Exhaust valves varied several times over the years and some were better than others, the new ones are silicone, work great and come in the service kit. 

The US Divers 1085 second stage can be found around the globe and in mass quantities.  Aside from being used as a backup they are often used as Safe Second Stages and a popular modification was to cut down the exhaust T's making the profile lower and easier to keep stashed until needed. 

Go out a grab a few.....Share with your friends
Be Safe....Have Fun....If you don't know ASK

Pet Peeve 101........The idea that the Bigger the Glob.....Better the Job is good.  Slathering on excess lubricant to parts that do not directly specify doing so is STUPID.  Packing second stage springs with silicone lube or putting it on diaphragms with a butter knife accomplishes one thing. It makes the perfect substance to adhere every tiny micro minute bit of sand and debris to the part.  You are basically making your regulator into a glue board from a roach motel but instead of roaches you get sand and other abrasive material attached to your regulator. 
Don't put lubricant on HP or LP seats, exhaust valves or the sealing and retention edge of diaphragms! It is not some magical substance that by contact turns parts into super sonic Tyrannosaurs Rex Kryptonite.  Just move your finger or brush away from the #10 can of lubricant!
If an O-ring or part calls for lubricant then wipe a little on, wipe 99% of it back off and look at the part. If the surface is shiny then you have enough.  Ok....rant over for now :)

1 comment:

  1. I have had good luck removing and replacing the exhaust tees by completely submerging in near boiling water until pliable. Use gloves when handling the hot components.

    Antique Diver