EVOL Mini leak

[Airgun-hobbyist]

Guessing that huge gap between the blue metal and oring is the problem? Also is the regulator supposed to look ‘worn’?

It is not the width the gap at all. The way the high pressure air seals, (and this happens in other places on other airguns than just the Evol), it pushes the o-ring into the gaps. Because of the nature of the titanium cylinder and the way it grows slightly when recharged, it expands and allows the o-ring to get into the gap. When it cools it is pinched on the sharp edge and starts to cut into it. The cutting and expansion and contraction turns the oring and peels a thin layer off from it causing an eventual leak. By "breaking" that sharp edge into a nice smooth corner it stops the cutting action.

When I install my re-ringed regulator, I push it down into the cylinder until it is just past the threads. Then center it on the receiver as I start to screw on the cylinder. This way the cylinder threads aren't being screwed onto the o-ring and aluminum regulator (evidenced by the missing blue annodizing). It will seat into place as you air it up the first time.

 

[pan60]

I would not be convenced its been apart but it has a bad case of nasty and to me the o-ring look shot.
I would agree with ctshooter and just go through it clean it and new o-rings.
these guys on here I am sure will help with any question you might run into just post pics if needed.

 

[ctshooter]

Hard to say if it's the previous owner or an owner before that, but that rifle has been apart many times. The telltale sign is the holes in the back of the barrel shroud the barrel tool hooks into. In the first pic of the OP you can see they have a good amount of wear. Since the barrel needs to be removed to get the airtube off it's a good indicator.

 

[American Air Arms]

90D Viton is the best for that location. Newer EVOLs use a teflon backup ring with a 75D Viton O-ring which essentially eliminates extrusion. The is an older regulator body.

The gap is normal and is intentional. O-Rings need to be fully presented to the high pressure air to properly seal.

Goo is probably the teflon grease from assembly combined with contaminates over time.
Make sure you check the internal O-Rings in the reg too. They can decompose over time.

 

[pan60]

Hard to say if it's the previous owner or an owner before that, but that rifle has been apart many times. The telltale sign is the holes in the back of the barrel shroud the barrel tool hooks into. In the first pic of the OP you can see they have a good amount of wear. Since the barrel needs to be removed to get the airtube off it's a good indicator.

I totally over looked that, good eye!

 

[RicL]

Thanks. That makes sense. The grease in between the threads is whiter than the goo around the orings.

Those contaminates, how do they normally get there and how can I prevent/reduce that?

Also, that goo made it all over the tube, a swab reveals what otherwise looks like a clean cylinder. What’s the proper way to clean the tube?

 

[Slugslinger]

Speaking of disassembly, I've seen in photos that the new HPS shrouded barrel is different at the receiver end than the original Evol models. And there is a new mod too. Will the existing barrel and mod tools work on these new HPS offerings.

 

[ctshooter]

To clean off all the grease use a 99.9% isopropyl alcohol. I get mine from Amazon in a spray bottle by MG Chemicals.

The white lube you see is Tom's recommended lube for the o-rings to prevent galling of the ultrafine threads which using silicon can cause. The lube is Ultimox 226 - available on Amazon.

Isopropyl Alcohol - MG Chemicals - 824-450G 824 99.9% Isopropyl Alcohol Electronics Cleaner, 15.9 oz Aerosol Spray, Clear: Soldering Tip Cleaners: Amazon.com: Industrial & Scientific
Ultimox 226 - Amazon.com: MicroLubrol Ultimox 226 Perfluoropolyether PFPE PTFE Grease Auto O2 205 206 226, 20g Jar : Automotive

 

[ctshooter]

Speaking of disassembly, I've seen in photos that the new HPS shrouded barrel is different at the receiver end than the original Evol models. And there is a new mod too. Will the existing barrel and mod tools work on these new HPS offerings.

I have both an Evol Mini .22 and a Mini HPS .30.

The barrel differences are for weight savings and the barrel wrench will work on all of them.
The moderator inserts are made by Silent Thunder Ordinance and are extremely effective for their size. Both the old and new designs utilize the Tesla Gas Diode that STO uses in their Falx, Sarissa and other moderators. I believe the new design is printed with a more robust material to handle the higher powers.

 

[RicL]

To clean off all the grease use a 99.9% isopropyl alcohol. I get mine from Amazon in a spray bottle by MG Chemicals.

The white lube you see is Tom's recommended lube for the o-rings to prevent galling of the ultrafine threads which using silicon can cause. The lube is Ultimox 226 - available on Amazon.

Isopropyl Alcohol - MG Chemicals - 824-450G 824 99.9% Isopropyl Alcohol Electronics Cleaner, 15.9 oz Aerosol Spray, Clear: Soldering Tip Cleaners: Amazon.com: Industrial & Scientific
Ultimox 226 - Amazon.com: MicroLubrol Ultimox 226 Perfluoropolyether PFPE PTFE Grease Auto O2 205 206 226, 20g Jar : Automotive

Thanks. Ordered. Spray bottle version too.

 

[RicL]

Finally got the ultimox 226 (first one lost in the mail). Are the machining marks normal? Hoping the previous owner didn’t run some brass brush or something

 

[Airgun-hobbyist]

Finally got the ultimox 226 (first one lost in the mail). Are the machining marks normal? Hoping the previous owner didn’t run some brass brush or something View attachment 18775

Yes, it's fine honing marks for the machining process. It will seal great.