Scubapro mark V

[kittyhawk]

o.k. thanks for the diagram. Same as the one i got sent. I'll go talk to my machine shop mate to have a batch made up. What do you guys think is a fair price for each $10.00 USD??
I'll get some quotes and get back to you. I can cut one myself for the odd job, but 10 and beyond, in stainless on my baby lathe... I'll get my mate to set up the CNC and go from there. Once he has the CNC file made up, it would be simple to keep producing a small lot.

Fingers crossed . Would update you guys later..

you guys want some hp seats rolled up too??

 

[HenrikBP]

What do you guys think is a fair price for each $10.00 USD??

you guys want some hp seats rolled up too??

US $10 would be a *very fair* price IMO. But let us know even if it ends up being more. I'd be in for some seats as well.

Henrik

 

[Couv]

Hello Kittyhawk,

Count me in for one turret bolt and put me down for a handful of seats too please (depending on cost). For O2 safe considerations, I was under the impression that they are made from Teflon though. (Educate me )

Could I suggest you start a new post in the DIY forum?

Couv

Edit: 21 JUL 09

I just did some quick research on the properties of Nylon 66 vs. Teflon and here are a couple of tidbits I uncovered, perhaps one of you sharpies can put thing in perspective for me.

ASTM D2863 is a method to determine the minimum concentration of oxygen in an oxygen/nitrogen mixture that will support a flaming burn in a plastic specimen.

On this website http://www.matweb.com/search/datasheet.aspx?matguid=06af5c6be5794be3ada05ff314300569&ckck=1 it shows the Oxygen index of Nylon 66 to be 21% where the Oxygen index of Teflon is > 95% ...this is all mumbo jumbo to me, but if I'm guessing correctly Nylon 66 will continue to burn at normoxic percentages where Teflon will not.

Again, I do not have a background in engineering so this may all be insignificant for this application.

Cheers,

Couv

 

[bax767]

I'd be interested in a turret bolt and a few seats also.

Bax

 

[kittyhawk]

I tried teflon, it was too soft and the piston knife edge starts to put a groove into the the teflon.. real quick.. got to do with the hardness of the product. I could use glass filled teflon, but who wants to breathe glass particles?? not me.. Other one to consider is PCTFE. KELF. All available in rods.

The problem with the groove is the IP stability and creep. you notice that your IP on the MK5 starts to drift downwards or was it upwards.. so you need to pack the spring to raise the IP back to 145PSI. There is also the risk of the piston knife edge siezing in the groove..

But you are talking about a MK5 here.. if you want to use nitrox. then you can consider machining up a sack of teflon and changing it after each dive.. or each 10 dives depending on what you found with the wear pattern.

Best thing about the MK 5 seat is that it's so easy to change. so theoretically you can machine any seat with a Nylon 66 wear property and try it out . The basic parameters are simple to test.

IP stability at 3000PSI and 500PSI. should be around 145 PSI. Run a tank of air through the reg and observe the wear pattern as well.

There is one other trick that I have not mentioned. That bad seat that you just tossed in the bin?? Well there is at least another 2 seasons left in it. You can pack the seat from the rear with some stainless washers. or acrylic discs. you just get some oil and gently polish the concave surface of the seat till the groove is gone. 400 wet and dry, then 1200 wet and dry, then 2000 wet and dry.. as long as the seat + disc or washer is the same thickness as the original hp seat.. Bob's your uncle.. Remember the groove is your friend and also your enemy!!

Still not heard back from my Engineer buddy.. he did mentioned that I would have to buy a full length of 316 stainless steel at 3.6 Metres..

will keep you guys posted.

 

[Boiler_81]

I would be interested in a bolt as well

 

[Jpope3]

Any idea where I could find the rebuild kit or parts for the MK V? I have one that was brand new when I closed my business 28 years ago. Never been used but a seat is bad in the first stage, from sitting unused so long, I suppose. Caused a high pressure creep.
Thanks.
JP

...and please disregard my question. Had I read the thread farther I would have found the advice about the seat and many parts from the MK10 being the same as for the MKV. Thanks for the info AWAP, DA and the group.

JP

 

[captain]

Odd it would be bad being the seat is not under any spring pressure when not connected to a tank and under pressure. I have a 30 year old MK V with the original seat. Also the seat can be reversed to the unused side but in your case both sides are unused.

 

[redacted]

I'm also surprised the seat seems to be a problem. I'd expect that you will want to replace o-rings and give it a good inspection. Take a real close look at the knife edge on the piston. Corrosion or a defect there could also cause IP creep even with a good seat. I'd give the seat another try befor replacing it.

 

[Jpope3]

Thanks for the advice, Captain and AWAP. It's been so long since I worked on these things I wasn't thinking diagnostically. I just heard what the technician said and took it for granted that he was correct. It makes perfect sense, though, that the seat should be fine. I'll go discuss it with him and ask him about the knife edge of the piston as well.

Thanks again. It's been a LONG time since I had one of these apart and I've obviously forgotten a lot.
JP