HP Seats

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Jonny Wishbone

Contributor
Messages
339
Reaction score
193
Location
West Central Florida
# of dives
I just don't log dives
Hey guys, so i ordered a pc of that fiberglass re-enforced 1/16" EPDM sheet from Mcmaster-carr to make 1st stage diaphragms which worked out really good. As we all know Dacor regs are only favored by a few old die hards and really like the swivel turret 960's. I have gotten some of those HP seats carried by NESS and Trident. They are great and work perfect. I know there are some NOS Dacor HP seats kickin around out there. VDH has them on his site. My concern with NOS HP seats is that the seat is still 20 years old or more and the composite seat substance has gotten hard (past shelf life maybe). I have had a NOS seat creep. Put in an aftermarket seat in the reg and she is rock steady. I took the Dacor seat and scraped/carved out the seat stuff just to play with it as i like to see what makes things tick. My question is,,,has anyone ever tried to replace the seat material in a seat like this? Does anyone know of a substance that could be used to "rebuild" these type of HP seats. This question doesn't come from being a cheapo looking to save a buck on a new seat, it is just that I like tinkering with stuff and sometimes my thoughts get carried away. Any thoughts out there?.....
 
@herman makes seats pretty regularly. He's off double hosing it up in Cozumel right now so he will be back next week. He probably will make them for you and honestly has probably already made some for that reg knowing him.

Material in the new regs is usually nylon, teflon is also used, 90duro viton on occasion but uncommon. He and @Luis H are probably the best people to ask for that info though. Luis is with Herman this week, so if you can be patient for a week, i'm sure they'll pipe in
 
Hey guys, so i ordered a pc of that fiberglass re-enforced 1/16" EPDM sheet from Mcmaster-carr to make 1st stage diaphragms which worked out really good. As we all know Dacor regs are only favored by a few old die hards and really like the swivel turret 960's. I have gotten some of those HP seats carried by NESS and Trident. They are great and work perfect. I know there are some NOS Dacor HP seats kickin around out there. VDH has them on his site. My concern with NOS HP seats is that the seat is still 20 years old or more and the composite seat substance has gotten hard (past shelf life maybe). I have had a NOS seat creep. Put in an aftermarket seat in the reg and she is rock steady. I took the Dacor seat and scraped/carved out the seat stuff just to play with it as i like to see what makes things tick. My question is,,,has anyone ever tried to replace the seat material in a seat like this? Does anyone know of a substance that could be used to "rebuild" these type of HP seats. This question doesn't come from being a cheapo looking to save a buck on a new seat, it is just that I like tinkering with stuff and sometimes my thoughts get carried away. Any thoughts out there?.....
I'm getting back into diving after over twenty five years. I replaced the HP seat in my trusty Dacor 950 with one from NESS and it worked great. The old one had some tiny pits in the seat material so I couldn't get it to adjust below 155 psi. I also replaced the seat in the XL Pacer second stage and the whole rig seems to be operating like new though I haven't had it in the water yet. I have a question about the 1st stage diaphragm. NESS recommends replacing it but I haven't found any available. The one in the reg looks like 1/8 thick rubber with a woven clothe sandwiched in the middle. It appeared to be in fine condition so I put it back in. I also didn't replace any of the O rings thinking I would wait to see if the new HP seat worked before investing the time and effort.
Does anyone have any insight into the importance of replacing the diaphragm or judging the condition of the original to see if it's worth keeping? Also, where's a good place to find O rings?
I gotta figure if someone is going to the effort to produce aftermarket HP seats for these old Dacors there must be enough of us still using them!
 
Yes, I am a Dacor fan, especially the 960 first stage with the swivel turret.I still have a few 960's with the original factory diaphragm in use and I can't tell the difference between a new diaphragm and an old one when using them. runsongas sent me this link McMaster-Carr I bought a sheet of it and it is AWESOME! to make diaphragms. Just use your old one and a pencil to trace it then grab some sharp scissors. There is some forgiveness for any irregular edges because the ledge or lip that the diaphragm sits on has room to cut slightly larger. If the original diaphragm is still very pliable and no cracking on either side when you fold it and roll it, I would just use it as it already has a "set" (broken in so to speak). I refuse to let my old Dacor's die.
 
Yes, I am a Dacor fan, especially the 960 first stage with the swivel turret.I still have a few 960's with the original factory diaphragm in use and I can't tell the difference between a new diaphragm and an old one when using them. runsongas sent me this link McMaster-Carr I bought a sheet of it and it is AWESOME! to make diaphragms. Just use your old one and a pencil to trace it then grab some sharp scissors. There is some forgiveness for any irregular edges because the ledge or lip that the diaphragm sits on has room to cut slightly larger. If the original diaphragm is still very pliable and no cracking on either side when you fold it and roll it, I would just use it as it already has a "set" (broken in so to speak). I refuse to let my old Dacor's die.
I saw a post that said if your HP seat has a hole all the way through it's for a compensated regulator and if not it's for a non-compensated regulator. The original in my Dacor 950 was no hole and the replacement from NESS had a hole through it but seems to work.
Anybody care to comment?
 
Hey Brilig, Just some additional FYI info: I have several Dacor regs that take the same HP seat, mostly 960's but have a 460 which is a balanced piston. it also takes the same HP seat. The one I replaced in a 960 that did not have a hole all the way through was a factory Dacor seat. All the other factory Dacor seats I have have the hole all the way through as well as the ones I have from NESS which is a Trident product. I think it is just a slight variation in manufacturing since the hole is only for the guide pin pushrod. The seats with the hole all the way through still have a step inside which the guide pin pushrod bottoms out against to keep it from going to far. If the seat looks good but you have a bit of either IP creep or unstable IP, you can use a small piece of 600 - 800 wet sand paper and rub the seat in a figure 8 pattern until you have a complete new surface. This has always worked for me and last quite a while. Some Dacor's use a volcano orifice and some have the cone built in to the bottom of the HP unit itself. If its the built in version, you can put a pencil in a cordless drill with the eraser out. Go slow and rub any corrosion off the edge of the cone down inside for a nice clean mating surface on the seat. If it's the version with a volcano orifice you can either replace the volcano orifice or take it out and use the pencil eraser on it as well. Either way this all seems to work just fine and I have only ever had to replace one seat using the Trident one. Hope this helps....
 
Hi Jonny Wishbone,

Kudos to you for not letting your "Old Faithfuls" die. I too was a Dacor owner and lover until I worked in a dive shop that did not sell that brand. The owner pretty much told me I had to teach with the equipment we sold.

At any rate, I have a chrome Dacor XLE Pacer (second stage) that could use a good home and some TLC. The exhaust Tee is in not so great of shape, and the snap ring that holds the purge button in place corroded away (replaced with a hardware store non-stainless one.)

It is yours for the price of shipping if you want it.

Couv
 
Hey Brilig, Just some additional FYI info: I have several Dacor regs that take the same HP seat, mostly 960's but have a 460 which is a balanced piston. it also takes the same HP seat. The one I replaced in a 960 that did not have a hole all the way through was a factory Dacor seat. All the other factory Dacor seats I have have the hole all the way through as well as the ones I have from NESS which is a Trident product. I think it is just a slight variation in manufacturing since the hole is only for the guide pin pushrod. The seats with the hole all the way through still have a step inside which the guide pin pushrod bottoms out against to keep it from going to far. If the seat looks good but you have a bit of either IP creep or unstable IP, you can use a small piece of 600 - 800 wet sand paper and rub the seat in a figure 8 pattern until you have a complete new surface. This has always worked for me and last quite a while. Some Dacor's use a volcano orifice and some have the cone built in to the bottom of the HP unit itself. If its the built in version, you can put a pencil in a cordless drill with the eraser out. Go slow and rub any corrosion off the edge of the cone down inside for a nice clean mating surface on the seat. If it's the version with a volcano orifice you can either replace the volcano orifice or take it out and use the pencil eraser on it as well. Either way this all seems to work just fine and I have only ever had to replace one seat using the Trident one. Hope this helps....
Thanks so much, Jonny. All this information is a great help. I forgot that the pushrod goes in that hole. I was starting to panic thinking that my ignorance was going to catch up with me at an inopportune moment. When I replaced the HP seat I put it back together with the original 33 year old O rings. I wanted to make sure it would work before I took it that far. What is a good source for getting replacement O rings? This regulator rebuilding could be an addictive hobby. I'm thinking of adding a pony bottle to my equipment list. Any suggestions on a make and model that would be a good fit for that application? What are some of the better old regulators to refurbish or a better question may be which ones to avoid? I used to work as a machinist so I find tinkering with these things to be a lot of fun. Now I just have too figure out all this "balanced, compensated, diaphragm vs piston" business so I can really add to the list of things I don't know that I don't know.
Thanks again Jonny Wishbone.
 

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