Alkin W31 2nd/3rd stage water separator issue

Please register or login

Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

Benefits of registering include

  • Ability to post and comment on topics and discussions.
  • A Free photo gallery to share your dive photos with the world.
  • You can make this box go away

Joining is quick and easy. Log in or Register now!

sunnyboy

Contributor
Scuba Instructor
Messages
855
Reaction score
334
Location
Vancouver Island, Canada
# of dives
500 - 999
On my last tank fill using my Alkin W31, I noticed a leak had started at the top of the water separator that sits between the 2nd and 3rd stages of the compressor (as opposed to the final water separator / filter unit).

The parts diagram shows the cap should unscrew, allowing me to change the o-ring that I suspect has failed.

However, the cap is smooth and I see no easy way of removing it without really scarring up the cap. It appears to be aluminum so will scar using almost any tool.

Has anyone had to remove this top cap on the water separator, and if so, how did you do it?

Again, this is not the part that also holds the filter as that's easy to open.

Thanks in advance,
-R
 

Namreg 58

Contributor
Messages
171
Reaction score
55
Location
Sydney Australia
I'm not familiar with the Alkin, but if it hasn't got two small holes in the top of the cap for a pin spanner, you can try one of the old style metal strap oil filter wrenches.
 
OP
sunnyboy

sunnyboy

Contributor
Scuba Instructor
Messages
855
Reaction score
334
Location
Vancouver Island, Canada
# of dives
500 - 999
No holes for a pin wrench, and it's too small for any filter wrench I have (only 2in dia). I've already tried a few things, and it is very tight - looks like it requires a lot of torque assuming standard thread (right-tight, left-loose).
 

iain/hsm

Contributor
Messages
888
Reaction score
504
Location
uk
There are a number of variants of the Alkin W31 from memory 3 or 4 including an earlier model.
Each variant was supposed to fix a problem with the previous build had that manifested itself during warranty.
This cost the original American distributor a lot of money fixing.

Out of warranty and your on your own and Im sure if you bought it from new you didnt get a copy of the Spare Parts Price List or you would have sold it to someone else by now. If you have bought it second hand then you too need a Spare Parts Price List. But also when these things were made they were around $4000 they were so popular with divers Alkin then went on to the airgun market as its an easier market and reduced the price to $3000 as a thank you for divers support.

Now the deal is on the 2nd stage separator. The problem happened when it was new and you have now run the thing between 492 hours and 786 hours filling your own tanks.

The cost to resolve the problem would have been around $25 in manufacturing and around £$15 in assembly from new.But no matter be prepared to buy a new complete separator tower.
 

iain/hsm

Contributor
Messages
888
Reaction score
504
Location
uk
Failing that the early ones the cap was on the bottom of the filter assembly, Then when they were gold anodized the cap was on the top of the separator. The latest ones are now clear anodized with cap and plug at each end with the tower separated between gas to the 2nd stage off the top side wall of the lower part and gas from the 2nd stage going in at the top side wall and out to the final filter at the top of the separator.

Clear as mud I know but this additional separation is because the older idea (gold colour filter) didnt work

The caps get jammed on because the threads streatch and expand as pressure is applied this in effect seals the cap onto the barrel solid. Add to this the 5 or 10 years of a non lubricated thread mated solid with the barrel and you have a problem removing it, we all have a problem removing it hence why you need a parts price list before you take on servicing an Alkin, and why the original distributor spent a small fortune mending them and why you should have sold it to some punk airgunner by now.

The bad news is the new silver (self colour) separators are even worse now with plugs top and bottom the threads now they will get solid with oxidation on the thread at both ends and as it goes in dry wearing off the protective anodising then the condensed water collected "wicks" down the thread making it as good as solid weld.

Put the small landing on the cap into a soft 1/2 plywood split half circle to protect and gain grip.
Then clamp the cap into the vice vertical with the cap clamped all around inside the plywood

It won't do much I guess but at least you tried. Anti clock wise to remove. Hope dies last
and Airgunners are your friend.
 
OP
sunnyboy

sunnyboy

Contributor
Scuba Instructor
Messages
855
Reaction score
334
Location
Vancouver Island, Canada
# of dives
500 - 999
Failing that the early ones the cap was on the bottom of the filter assembly, Then when they were gold anodized the cap was on the top of the separator. The latest ones are now clear anodized with cap and plug at each end with the tower separated between gas to the 2nd stage off the top side wall of the lower part and gas from the 2nd stage going in at the top side wall and out to the final filter at the top of the separator.

Clear as mud I know but this additional separation is because the older idea (gold colour filter) didnt work

The caps get jammed on because the threads streatch and expand as pressure is applied this in effect seals the cap onto the barrel solid. Add to this the 5 or 10 years of a non lubricated thread mated solid with the barrel and you have a problem removing it, we all have a problem removing it hence why you need a parts price list before you take on servicing an Alkin, and why the original distributor spent a small fortune mending them and why you should have sold it to some punk airgunner by now.

The bad news is the new silver (self colour) separators are even worse now with plugs top and bottom the threads now they will get solid with oxidation on the thread at both ends and as it goes in dry wearing off the protective anodising then the condensed water collected "wicks" down the thread making it as good as solid weld.

Put the small landing on the cap into a soft 1/2 plywood split half circle to protect and gain grip.
Then clamp the cap into the vice vertical with the cap clamped all around inside the plywood

It won't do much I guess but at least you tried. Anti clock wise to remove. Hope dies last
and Airgunners are your friend.

Thanks very much Ian. I do appreciate the background information. I attached a few photos of my compressor, as well as two of the actual separator. It has a hose clamp on the top cap just to try and minimize scarring of the metal as I try and remove it. (the leak is between top and body where the sharpie mark is)
T800_Alkin W31 compressor 2021-04-20 01.jpg
T800_Alkin W31 compressor 2021-04-20 02.jpg
T800_Alkin W31 compressor 2021-04-20 03.jpg
 

iain/hsm

Contributor
Messages
888
Reaction score
504
Location
uk
Heck No dont use that jubilee clip you will damage the aluminium.
Use hard wood something like 3/8 thick plywood.
Cut a hole just smaller than the 2 inch diameter in a 3/8 sheet of ply with a jig saw.
Then cut across to make two equal halves of wood
Then use the wooden blocks you made as packers in place of that jubilee clip in a vice
Then grip one of the steel tube fittings and use that to remove.

You may also/should use a release agent like WD40
You need to flood it inside down the holes.
Forget cleaning and nitrox considerations you need all the help you can get to remove the plugs
Let it creep down the threads overnight hopefully you can release the oxide lock.

You can easy clean the junk off after you release the caps.

For clamping an alternative is to buy a 2 inch plastic pipe clamp, that comes in two halves.
See below the Stauff pipe clamps you only need the two plastic halves.
Use the cheap plastic green ones they are a couple of dollars, not the expensive once like below
You only need the two green plastic halves


STAUFF Introduces ACT Anti Corrosion Technology Clamp | STAUFF USA


STAUFF_ACT_Clamp.jpg
 

iain/hsm

Contributor
Messages
888
Reaction score
504
Location
uk
If and only if you manage to shift the plug a little, stop and pour in more WD40 and wiggle back and forth
rather than damaging the threads by running it out in one go.

Also I would use a plastic hammer and wack that steel fitting centre line rarther than use a spanner (wrench) or cover with a 2x2 wooden vlock and wack the heck out of it with a big 4lb lump hammer. If after its moving then you can use a crescent wrench on that steel side fitting.

Try not wacking the soft brass fittings or the drain knob

Once it starts to move then also spray the WD40 into the gap made between Plug thread and shell externally. That way both ends of the thread get lubricated.
 

rjack321

ScubaBoard Supporter
ScubaBoard Supporter
Messages
11,971
Reaction score
7,180
Location
Port Orchard, Washington State
# of dives
1000 - 2499
On my last tank fill using my Alkin W31, I noticed a leak had started at the top of the water separator that sits between the 2nd and 3rd stages of the compressor (as opposed to the final water separator / filter unit).

The parts diagram shows the cap should unscrew, allowing me to change the o-ring that I suspect has failed.

However, the cap is smooth and I see no easy way of removing it without really scarring up the cap. It appears to be aluminum so will scar using almost any tool.

Has anyone had to remove this top cap on the water separator, and if so, how did you do it?

Again, this is not the part that also holds the filter as that's easy to open.

Thanks in advance,
-R
Mine doesnt leak but didnt seem to be efficient anymore and I felt like I should clean the bronze element inside.

Yeah no lol. It is welded into a solid mass. If you manage to get yours apart without ruining it please let me know how
 
OP
sunnyboy

sunnyboy

Contributor
Scuba Instructor
Messages
855
Reaction score
334
Location
Vancouver Island, Canada
# of dives
500 - 999
Thank you to both Ian and Richard. I got it apart, and it turned out to be very easy!

Ian, I love your idea and wish I'd read it before I got it apart. As a result, I did score the aluminum cap somewhat, but I'm OK with that and a little light buffing should have the worst marks out.

I used a chain wrench (vicegrips) together with my big shop vice and a thick rag. I put the rag around the main separator, then used the vice more as a movement stop than a clamping device. My left hand kept the separator down. I then locked the chain wrench around the cap and using just simple firm pressure (no cheater bar or extra torque) it came free.

As soon as it was loose it is easy to unscrew by hand. The threads are pristine, which is more than I can say for the o-ring. It's pooched. (see photos).

Again, thanks very much for the assistance, and the moral support!

-Richard

T800_Alkin W31 compressor 2021-04-21 01.jpg
T800_Alkin W31 compressor 2021-04-21 02.jpg
T800_Alkin W31 compressor 2021-04-21 03.jpg
 
https://www.shearwater.com/products/swift/

Top Bottom