Sherwood Magnum Blizzard (second stage) overhaul

[nldiver1984]

I bought a used pony bottle yesterday with good hydro. It came with an old Sherwood Magnum Blizzard second stage, and an Aqualung Conshelf Supreme first stage. The Conshelf seems to be a fairly easy rebuild, but I'm having trouble finding the right kit for the Blizzard.

Here are a couple of pics I took of the interior and exterior:

I'm unable to remove these metal fins which have some corrosion on them. Is there a trick to this? Also, what else do I need to clean here?

When I put this diaphragm next to a light and stretch it a little, I can see a very tiny pinhole.
the

Can't seem to detach this orifice from the hose either. Is there something I can use to loosen its grip?

Also, there's a metal pin next to the purge button that seems to prevent the purge from being pressed. Is this necessary and can I remove it?

The outer ring of the regulator seemed to have some kind of glue attaching it to the base. Now that the glue is removed the outer ring keeps popping off. Some silicone perhaps?

Thanks.

 

[KeithG]

I bought a used pony bottle yesterday with good hydro. It came with an old Sherwood Magnum Blizzard second stage, and an Aqualung Conshelf Supreme first stage. The Conshelf seems to be a fairly easy rebuild, but I'm having trouble finding the right kit for the Blizzard.

Here are a couple of pics I took of the interior and exterior:

View attachment 447011

I'm unable to remove these metal fins which have some corrosion on them. Is there a trick to this? Also, what else do I need to clean here?

View attachment 447012

When I put this diaphragm next to a light and stretch it a little, I can see a very tiny pinhole.
the
View attachment 447013

Can't seem to detach this orifice from the hose either. Is there something I can use to loosen its grip?

View attachment 447014

Also, there's a metal pin next to the purge button that seems to prevent the purge from being pressed. Is this necessary and can I remove it?

The outer ring of the regulator seemed to have some kind of glue attaching it to the base. Now that the glue is removed the outer ring keeps popping off. Some silicone perhaps?

Thanks.

I suggest you grab the manual from frogkick.de look for SRB3200, SRB3300, SRB3400 manual. It will give parts explosion and service instructions.

The metal pin by the purge is to be engaged during storage - it slightly depresses the purge and removes pressure from the seat.

The fins detach by simply unscrewing the 2 mounting screws. You may have some issues with seized screws?

The outer ring of the regulator screws on. If it is popping off then the threads have been damaged. This means either the ring or the housing is screwed.

Both the hose and the orifice have standard hex wrench fittings. The hose simply unthreads. The orifice does not turn in the housing since it is fixed by an internal nut.

Pinhole in the diaghram? Not good news.

 

[207diver]

diaphragm may still be available but I'm not sure. You really don't need a kit if you can source the correct LP seat the only other o-rings are the hose ends, orifice, and the big o-ring between the housing and the inlet. Pay very close attention to the housing around the inlet they tend to crack and the housing are NLA.

If the cover ring or housing is damaged its not going to be salvageable anyway a good quality comparable second stage can be purchased at an affordable price. You have a good solid first stage though!!

 

[KeithG]

diaphragm may still be available but I'm not sure. You really don't need a kit if you can source the correct LP seat the only other o-rings are the hose ends, orifice, and the big o-ring between the housing and the inlet. Pay very close attention to the housing around the inlet they tend to crack and the housing are NLA.

If the cover ring or housing is damaged its not going to be salvageable anyway a good quality comparable second stage can be purchased at an affordable price. You have a good solid first stage though!!

I forgot - service kits are readily available on ebay and other suppliers.

 

[nldiver1984]

I forgot - service kits are readily available on ebay and other suppliers.

For which model number should I search for parts? I checked on Vintage Double Hose but they only have kits for pre-1992.

It seems like an easy reg to fix other than that pin issue. When I press on the purge button the pin blocks the button from retracting all the way. Should it be something to worry about?

Any idea how I could get rid of the corrosion from the metal and plastic parts?

 

[JamesBon92007]

I
Both the hose and the orifice have standard hex wrench fittings. The hose simply unthreads. The orifice does not turn in the housing since it is fixed by an internal nut.
Pinhole in the diaghram? Not good news.

I find the statement "the orifice does not turn in the housing" a bit confusing--care must be taken to insure that it doesn't turn inside the housing or it could damage the plastic. I just thought that should be a little clearer

Soaking in vinegar will remove some or most of the corrosion.

The pin that holds the purge button down during storage should stay in the "out" position when the regulator is in use. It has a small spring on it. If it doesn't stay out then the spring must be bad or stuck due to corrosion.

If the diaphragm has a hole in it you need a new one. That may or may not be easy to find. The same diaphragm probably fits many second stages. Repair kits are available on eBay and other sources. If you Google "Sherwood Magnum regulator kit" it should give you some links.

Does the little wheel on the demand lever turn freely? Is there corrosion on it? I have had good success using a tiny amount of muriatic acid on the wheel and lever only but I only leave the acid on for 4-5 seconds at the most and rinse thoroughly and immediately. I only do this if the wheel is noticeably corroded and not turning freely. Then a little spray silicone but be careful not to get the silicone on any plastic as it might dissolve it to some extent--hold a paper towel or rag behind it went spraying. You may have to coax the two little tabs on the wheel axle to loosen it up a bit.

Have you had the second stage in a bucket of water attached to a tank? If you get a slow leakage (or if you can hear air escaping when the air is on but you are not breathing trough it or pushing the purge button) then the valve seat is leaking. Remove the hose from the regulator using two wrenches. Find a blade screwdriver that fits correctly inside the air inlet and while depressing the purge button turn the screw slot about 1/8 of a turn clockwise. Reconnect it and see if the leak has stopped. The valve seat can sometimes be flipped over and I'll use a dot of contact cement to hold it in place. On that screw slot (adjustable orifice) that you turned 1/8" clockwise, you can remove the adjustable orifice by unscrewing it counterclockwise. It might get stuck and need a little coaxing. Once you get it out clean the inside thoroughly (q-tip with some silicone grease on it usually works for me), clean the adjustable orifice and install a new O-ring lubricated with silicone grease.

If the housing won't stay screwed together then it is screwed As has already been stated you will need a different second stage (unless you are like me and will put some screws in it or something ) On those kinds of repairs I generally only use it for scrubbing the algae in the swimming pool.

I'm guessing that this is the manual you need (keep in mind it's a guess):

https://www.divestock.com/downloads/dl/file/id/282/sherwood_srb3200_srb3300_srb3400_srb3400.pdf

The manual should explain how to adjust the demand lever and how to fine tune it. This is done with a slotted tool. This type of second stage is not rocket science and we are using such tools as: two end wrenches, a screwdriver, a bucket of water, vinegar, Q-tips, etc. The slotted tool to adjust the demand lever can be improvised.

 

[KeithG]

I find the statement "the orifice does not turn in the housing" a bit confusing--care must be taken to insure that it doesn't turn inside the housing or it could damage the plastic. I just thought that should be a little clearer

Agreed. And a very good point.

 

[nldiver1984]

Agreed. And a very good point.

Sorry I meant the hose connector wouldn't "turn" but this has since been rectified.

 

[nldiver1984]

Seems like the hardest part to find is the diaphragm as I'm not sure of other ones that would work.

The ring piece keeps slipping off and it seems that someone had glued it on to the housing at some point.

I'm concerned about that little pin in the front not having a spring. That could cause an incident if it prevented the purge button from closing all the way.

Because it's going to cost at least $70 to fix this reg I think I should just get another one. In the meantime can I use the octo on my primary rig on the pony instead, so in case I do need to help someone I could just give them my pony rather than have them attached to my tank?

 

[JamesBon92007]

Seems like the hardest part to find is the diaphragm as I'm not sure of other ones that would work.

The ring piece keeps slipping off and it seems that someone had glued it on to the housing at some point.

I'm concerned about that little pin in the front not having a spring. That could cause an incident if it prevented the purge button from closing all the way.

Because it's going to cost at least $70 to fix this reg I think I should just get another one. In the meantime can I use the octo on my primary rig on the pony instead, so in case I do need to help someone I could just give them my pony rather than have them attached to my tank?

If it's only the metal "bezel ring" you can leave it off. As for the little pin, personally I would remove the purge button and the little pin and soak them in vinegar for a couple of hours and see how well they clean up and if the pin spring is damaged/broken or simply corroded. Getting the correct diaphragm might take some research as the part number in the manual does not seem to match the part numbers on the diaphragms I'm seeing for sale on eBay. However, I suspect that they are somewhat interchangeable between different Sherwood models but it might take a testimonial from someone who's actually substituted one to be sure. I'll check the one's I have (Magnum, 3100, and 4000) and see if they are the same. If you can't get the little metal pin working you could leave it off but it's there to prevent leaving a permanent depression in the valve seat. You could possibly just stick the pin in there when you are not using the regulator. Lots of other Sherwood models do not even have the pin so that should tell you something.



How are you coming up with $75? I'm seeing diaphragms for around $8 and service kits for around $15. The kits don't usually include a diaphragm because they seldom wear out. Other than possibly containing a replacement spring for the little pin there's just a couple of O-rings, a new valve seat, and a cable tie if the kit is for the second stage only. Some kits might include the adjustable orifice but it seems unlikely it would wear out. When you get to the point where you keep O-ring sets in stock you will likely have most of the ones you need on hand. This is an example:

SCUBA/NITROX O-RING KIT VITON 12 SIZES 166 PC 90 DURO ORK-SCUBA1 V90 | eBay

Edit: I checked and the second stage diaphragms for the Magnum and the 3100 are exactly the same. The 4000 does not unscrew so it is a PITA to get apart so I didn't check that one.