Type of O-rings to be used on 1st Stage

[dhillman]

Hello again. I've read a lot about replacement of 1st stage o-rings but not clear about the typre to be used. Can I use PU90 for all the dynamic O-rings inside the 1st stage? For the static, should I use Viton 70 or should I still use the PU70 or 90? What about the color of the O-ring, does it matter? Between Polyurethane and Viton, O-ring USA, has the Military, should that be the choice if PU is not indicated? Sorry for the many questions, I ordered the book by Vance Harlow but haven't arrive yet, don't know if the answer is there.

Any comments will be appreciated.

Thanks,

Darrel

 

[redacted]

What regulator are you talking about? PU o-rings are a bit more expensive (quite a bit more if you can get the cast variety rather than the milled ones) than others which are as good or better in most applications. I only use PU o-rings (PU 2-010, duro 90) in the HP piston application on some of my Scubapro BP 1sts when I have extrusion problems with other materials (also in duro 90). This problem manifests itself as abnormally high IP at high tank pressures and in spec IP at moderate and low tank pressures. All the rest of the o-rings on my Scubapro regs are EPDM or viton in duro 70 or 75. In a pinch, I'll still use nitrile o-rings if I don't have the more O2 tolerant varieties available.

 

[dhillman]

Thank you. The regulator is a SP Mk10. Good information you have given me. Matt recommended the PU90-010 for the HP piston, but when attempted to order those from O-rings USA found out that comes in a bag of 100 for $30.00. I tried through Amazon.com which sell them in a package of 2, but the shipping charges are $25.00 to SJ, PR. Thank you for the information, I will go for the VITON 75 on the rest of the O-rings. What is the light blue color of the SP O-rings for? Color coding or a special material? Thanks again.

Darrel

 

[halocline]

Personally I would avoid viton o-rings unless you're planning on high percentage O2 use. Viton is supposedly not as good as EDPM, nitrile, or polyurethane for extrusion. I would just use the BN70 series from oringsusa.com for most applications. I see that they have changed their policy on quantity for the polyurethane duro 90s, they used to sell those individually. Oh well, it was good while it lasted. If I were ordering right now, I'd probably just get the nitrile duro 90 for the HP piston, maybe also for the HP seat seal, and duro 70 for everything else. Color does not matter.

Awap likes the EDPM, and I've heard that's what SP uses in their kits, but comparing those to the nitrile ones I've bought from oringsusa I can't tell any difference. Couv is pretty knowledgeable about various o-rings so maybe he'll chime in.

 

[redacted]

Thank you. The regulator is a SP Mk10. Good information you have given me. Matt recommended the PU90-010 for the HP piston, but when attempted to order those from O-rings USA found out that comes in a bag of 100 for $30.00. I tried through Amazon.com which sell them in a package of 2, but the shipping charges are $25.00 to SJ, PR. Thank you for the information, I will go for the VITON 75 on the rest of the O-rings. What is the light blue color of the SP O-rings for? Color coding or a special material? Thanks again.

Darrel

I believe they used to sell them in small quantities. Looks like they changed it. If you can wait, I'll talk to Mattboy about a group buy. If you just need one to get by, PM me your address and I should be able to spare one. Anybody else want in on a group buy, please post here.

Scubapro used to color code there o-ring about 10 years ago. Now they are mostly black but some are still color coded by a light colored band on the otherwise black ring. I believe this is used to discriminated between different materials in the same size o-ring.

 

[dhillman]

Great information thank you all. Put me in the list to order the PU90-010. I can take a third of the bag if it make it easier. More questions coming: Is there a place where I can get the Mk10 seat, the same way as I can get the generic O-rings? I've been trying to get an annual kit of the SP Mk10 but no success. I tried the Scuba Store in Spain, e-Bay, and some guys around, but no answer. If I can get the seat and the O-rings, I think I'll be all set. Also, what is the sign of an extruded HP O-ring? Higher IP??? Thank you. Darrel

 

[halocline]

I wouldn't worry too much about the PU 90 o-ring. There are several thousand MK10s in the world working just fine without them. Just get the nitrile ones from o-ringsusa, that will get you started, and when awap can get the group order together you can try some of those.

You should consider getting the Vance Harlow book right away. It's available at: SCUBA REGULATOR MAINTENANCE AND REPAIR by Vance Harlow

That book will explain all about o-ring extrusion and is really good for specific techniques for the MK10, like removing and installing the HP o-ring without scratching the critical sealing suface of the reg body. You're a dentist, I think you said, so you already have an excellent assortment of tools that you can use as o-ring picks, although my experience with dental picks is that they're very sharp and made out of hardened steel, so they can easily scratch the brass reg body and destroy o-rings.

I'm sure someone mentioned this, but scubatools.com will have a few things you'll need. For sure you'll need a piston bullet tool and you'll need something to remove the yoke nut. (unless your reg is DIN)

 

[Luis H]

I would be interested on some of the PU90 O-rings.


Hi dhillman

I don't want to hijack this thread, but I am curious who the Scubapro dealer in the San Juan area is now a day?

I worked for Divers Service Center (for Alberto Umpierre) in the 70's and we where the Scubapro dealer back then, but Alberto told me recently that he wasn't anymore.

Have you tried to get parts from the Scubapro LDS.

I know The Dive Shop in Mayaguez is a Scubapro dealer, but I don't know if they would sell you parts.



Buena suerte

 

[dhillman]

Hi Luis. Yes I knew Umpierre. My first Hydrostatic tests were done there when I had steel tanks at that time. The new dealer in the metropolitan area is a place called Scuba Dogs, but I am not to happy with them. I did ask them if I could fix the Mk10 after the annual maintenance done by them, becuase of a leak at the swivel, but they said only to be done by a certified technician. Thanks for asking. My Mk10/R150 was bought at La Cueva Submarina in Isabella in 1990. I do have the lifetime warranty card but had never use it.

Nice to know of someone familiar with the area. I am very glad I hit this forum, very grateful for the willingness to help. Thank you all again.

Darrel

 

[Luis H]

Well, it is kind of a small world. I did part of the installation of the hydro test machine at Divers Service Center. Basically Alberto and I dug the hole in the ground for the deep tank chamber.

I was visiting last November and saw that the whole machine was painted white, but other than that it looked the same as 30 years ago. I notice he has a new small hydro test chamber so I am not sure if he is still using the old one, the one in the back corner.

You may want to try the shop in Mayagüez, I think the owner is Jaime Braulio Jr. (I can’t remember his nick name, maybe Papo). He is very friendly and they have been Scubapro dealers for about 40 years or maybe more.