Really, how much creep is a problem.

[herman]

Professionally done and impressive! Scuba hacker, I think they all hate you now hehe :cussing:

Herman, for Mk2 seats do you think if I just insert a small piece of the teflon material in an old
piston and then trim off the sliver would work? I'm excited.

It should, I did the first ones that way. The big problem is getting the first cut straight so it lays flat in the bottom of the piston. I have the machine tools and materials so I am motivated to make tools as I need them......god help me if I get...make that when... the milling machine I want, the wife may never see me again. The cutting block is not difficult to make and will save you time in the long run. It is just a block of aluminum, a piece of flat stock 3/8in or thicker would do fine, with a hole drilled in it with a standard sized drill bit. It could be made with a hand drill but a drill press helps, if you don't have one, odds are someone you know does.

I went back to the shop several hours later and the IP was still the same, if it holds for 3 or 4 hrs that is good enough for me.

Luis, there are 2 envelopes coming, I had made some of the rounded ones with the pin inserts the next day. Hope they are what you needed. Fun little project.

 

[AquaNSun]

This will become my project now YES!!! Im going to make the block as you said. Herman, I ordered from Mcmaster the Teflon, 8546K32, with hardness D55 to start with and wanted to see how it goes. How do you feel about the hardness D50 you have right now?

 

[Zung]

Yeah, awesome!

If I'm permitted to spoil the fun a little, how about wear? There's a report by kittyhawk about the MK5 here that says:

"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."

 

[herman]

This will become my project now YES!!! Im going to make the block as you said. Herman, I ordered from Mcmaster the Teflon, 8546K32, with hardness D55 to start with and wanted to see how it goes. How do you feel about the hardness D50 you have right now?

So far so good, this is in the early testing phases so they may prove to be inadaquate. I am having a little more trouble with the MK-5 but the clone seems to be doing nicely after it had time to seat in. Guess time will tell but I enjoy the experimenting.

The McM stock should do unless it's on the big side of the tolerance, in which case you will have to reduce it down some. You can reduce a short section - maybe 2 inches long with 1 inch exposed at a time- by clamping it in a drillpress and sanding it down with sandpaper. I would wrap the sandpaper around something flat and an inch or so wide, a file works nicely. Use a fine grade of sandpaper 600-800 at least, you are working with .001s of an inch so go easy. Sand a little, test and sand some more.

Yeah, awesome!

If I'm permitted to spoil the fun a little, how about wear? There's a report by kittyhawk about the MK5 here that says:

"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."

So far I seem to be having the exact opposite problem, not cutting in fast enough to suit me but I am using flat seats as opposed to ones with a depression in them like the SP originals, may be some difference there. That is coming soon. There may be different hardnesses of teflon as well which would account for different outcomes. In any case, this is just some experimenting I am doing and thought the members might like to see what I was doing. It's not something I would suggest the average diver try nor would most want to....me, I could never leave anything alone for long before I had it apart to see what makes it tick.

 

[Zung]

You'd be doing a great service to humanity if you drive this other project simultanously to simulate/accelerate wear. Plus you've already have a firm order

 

[herman]

You'd be doing a great service to humanity if you drive this other project simultanously to simulate/accelerate wear. Plus you've already have a firm order

Since you bring it up, let me ask a question. Is there any reason you would want to cycle the second stages? I see no reason to do it myself and I have some ideas for a much simpler device that only cycles the first stage. If there is a reason to do so fine but I don't see it.
Luis if you are around, same question to you- or any one else for that matter. .....I may need that milling machine sooner than I thought. Twist my arm to do this please....but honey they forced me to buy it.

 

[Couv]

..... I do not have a fancy machine like the master has posted, but I do have the DIY version. I'll post pictures when I get it back as it is now on loan to a friend. But it is pretty simple. I bought a 175 psi pneumatic relief valve from Granger and put on a couple of adapters so I could screw it into a first stage l/p port. This way I can remove all of the hoses and conserve lots of air when I do the first stage cycling. Air on/air off/pull the ring, pfffft! One cycle. Do that about 30 times and then hook up my IP gauge (also with a very short hose.) .....

Here you go mate: Coonass First Stage Cycling Device:

 

[herman]

Hummmm I have one of those already...darn relief valve on my IP gauge (same type) will blow off like a machine gun it I have a runaway IP, scares the dickens out of me but beats a blow hose.

After a conversation I had with Luis, I am thinking there is a need for 2 different types. One for experimentation and another just to use for setting seats.

 

[Couv]

Herman,

I have it separated from my IP gauge because I don't want to cycle the regs that many times with the gauge installed because it would not be good for the gauge. Plus, if I want to leave the 1st stage hooked up overnight with no second stage attached, the lp side will be protected.

But, yes, it would be handy to have two. One to do the cycling and another to use with the IP gauge that could be hooked up to an "unknown."
c

 

[Zung]

I agree that cycling any stages 10-20 times by hand to set a new seat is no big deal, and couv's device certainly makes an interesting saving on air at $10 a fill over here.

The thing is, I've some questions about the wear of after market or home made seats, like the Trident ones awap reported elsewhere; that one lasted 40 dives hours.

Another thing that bugs me is the claim that SP made for the newer seats for the MK10+/20/25: they said these last over a million cycles "without any noticeable engraving...even under a microscope". I've got 2 or 3 I replaced that have marks clearly visible to the naked eyes, but I've got these off eBay and I don't know how many dives they have.

Anyhow, for these long term testing, some mechanical help is very desirable. I certainly don't want to wear any of my fingers out, even the one that had been bitten by a morray and consequently has reduced capacities.