Scubapro MK20/G250: Ten Years After

[Six2Life]

Uh oh...

I'm predicting a run on early 90's vintage G250's.

 

[Couv]

I like it, the only down side would be the stem does not have a second groove for a wiper o-ring, but that's not a big issue. I would bet that stem o-ring is a 1.0mm x 2.5mm

Just drill the center hole in the Awap seat if you don't have a punch.

Re the little hole in the poppet. I always assumed that was just to relieve the pocket of air that might get trapped under the seat.

Tried that, there're actually 2 holes, 1 on each side, but the center rivet is holding the seat down very firmly. Oh well, the Trident seats are not that hard to get...

Edit

But, wait! Look what a properly sized watchmaker's screwdriver can do!

View attachment 103155

External diameter 6.95mm, width 1.95mm, and the diameter of the pin is 2.00mm. It's flippable and awapable! Just let me figure out a way to punch the center hole...

 

[Zung]

Ordered a hole punch.
Men like toys

And yes, the o-ring is a 1 x 2.5mm.

 

[Texfrazer]

Dang! Now I'm going to have to keep my eyes open for another type of 2nd stage.....

 

[Zung]

Just received my new toy, I have to show it off:

A brand new 2mm hole punch from the 'Bay for $4.26 shipped; originally designed for watch straps. Using the old seat as a guide and doing a brand new awap seat:



OOPS, some alignment problems



But once fitted, it doesn't look too bad:



Does it work? I think it should. What do you think?

 

[Couv]

Just received my new toy, I have to show it off:

A brand new 2mm hole punch from the 'Bay for $4.26 shipped; originally designed for watch straps. Using the old seat as a guide and doing a brand new awap seat:

View attachment 104070

OOPS, some alignment problems

View attachment 104072

But once fitted, it doesn't look too bad:

View attachment 104073

Does it work? I think it should. What do you think?

Yes, I think it will work just fine.

 

[redacted]

Just received my new toy, I have to show it off:

A brand new 2mm hole punch from the 'Bay for $4.26 shipped; originally designed for watch straps. Using the old seat as a guide and doing a brand new awap seat:

View attachment 104070

OOPS, some alignment problems

View attachment 104072

But once fitted, it doesn't look too bad:

View attachment 104073

Does it work? I think it should. What do you think?

Looks good. It may need a dab of rubber cement to seal the rivet to the poppet. If it works, I think I have a couple more grey poppets you can have.

 

[Zung]

So I took a 109, the one I reported here, and substituted this grey poppet.

• Before: cracking pressure 22 mm / .9 inch
• After : cracking pressure 22 mm / .9 inch

And I didn't even touch the orifice. What a piece of precision engineering!
I'm leaving the thing to "age" a while and report back if there's any change.

Btw, the rivet seems to hold pretty well by friction alone, impossible to remove it with my finger nail; I have the feeling that glue is optional.

 

[Texfrazer]

Excellent job Zung!