Recreating ancient seals...

[DocsMachine]

Sydarm?

-Anyone know? I have a Sydarm around here somewhere, but it hasn't seen a 12-gram in a decade. And I'm not sure I've had the reg apart since a few years before that. I can dig it up, too, and have a look, but in the meantime, I'm sure somebody here knows.

Here's what I have archived from way back.

-Looks right, and both the Dyna and the Hyper are identical internally.

yeah, its one of the old stock pre-dye matrix centerflag HPR's... it creeps, i tried to resurface it and thought i did a good job, so there might be some slight dimensional inaccuracies, it did nothing.. but on the plus side it didnt make it any worse...

-Be happy to have a look at it. Do you have my mailing address?

Doc.

[Tracker]

not offhand, ill message you for it

[superman]

Only seal I could think of is a super tiny seal that fits between the top and bottom tube on the sydarm. I have had to replace it once. Other than that everything else should be standard mag orings.

[Levi]

These are the ones I'm suspicious of.

[superman]

Where do those go? I am sure those could be replaced with urethane. Are they thicker than a standard agd oring?

[Levi]

Not sure. I really don't know the Sydarm internals well. I'll measure up those O-rings this evening. Maybe pull my Sydarm apart this weekend and have a look if an expert doesn't come along. The fact that the classic valve kits are available from AGD but the Sydarm kits are not is suggestive that there is something unique going on.

[Levi]

I just found this gem on my hard drive. The carpet makes me think I may have taken this picture myself. If so, there's a chance I might still have the physical copy somewhere.

[ford]

As a person with lots of Dyna/Hyper Flows sitting in my closet collecting dust, this is the most riveting thread on MCB yet.

[imped4now]

Agreed. I probably have ~10 Centerflags alone, along with plenty of other awesome old mounted tank regulators.

[DocsMachine]

Levi's diagram points out something I missed yesterday, and only realized last night as I was doing up my notes on this: The translucent plastic thing isn't the seal. The seal is in the front piston- as shown in the drawing- and is a simple urethane disc. (That I even already had the right size punches for.)

So a rebuild kit will be even easier than I thought. I'll be ordering up some O-rings (a bunch, actually, I have three or four kits to put together already) and once those come in, I should be able to put together some solid kits in short order.

Still haven't dug out my Sydarm or Bulldog, and still looking for a second Flatline 4500 owner that has access to a full 4500 fill- on a legal tank, hopefully- and can do some solid testing of these new reg seats for me.

Doc.

[Levi]

The old local shop I used to go to has closed. I'm going to swing by the new PB/Airsoft store tomorrow and see if they do 4500 fills. If they do then I'd be happy to test in my flatline.

[Levi]

Look what I found!

[scottieb]

That's a gold mine right there! I'd love to rebuild my Centerflag regs. They were the best!

[Levi]

Includes the little hard plastic seat/piston thingy. The o rings are long past the use-by date, but the hard plastic part doesn't seem like something that age as poorly.

[Levi]

Here's what the Sydarm kit looks like. It all looks like standard fare classic mag stuff except for two items. The blue O-rings at top right, and a steel spiral retaining ring immediately to the right of one of the reg seats.



Blue O-rings: The color suggests they are fluorosilicone not urethane. https://www.globaloring.com/oring-colors/





The spiral retaining ring measures as follows:
ID: 0.445"
OD: 0.537"
Wire thickness is 0.018" and the clip makes a little more than 1.5 turns, so where there is overlap it is 0.036" thick.



The kit labels this as "SPIRAL CLIP-PIERCE ASSEMBLY" and I'm pretty sure the blue O-rings are "O-RING PIERCE PIN OD"



The O-rings seem to fit nicely around the neck of a 12g, so I'm guessing that is where they go. I wonder why they used this particular material. I don't know if this is just a matter of Tom Kaye overkilling it for the sake of overkill? Or if there was a particular problem they were engineering around?

[Trygve]

Yes youre correct thats where the blue o ring goes. My sydarm was leaking from the 12g chamber couldnt figure it out for the life of me. Found the remnants of a sticky black o ring inside the the neck of the pierce assembly. Really hard to see and remove. Get a flashlight and a dental pick. Replaced it and it fixed the leaking.

[Levi]

Here's a shot of the other side of the label which shows the rest of the kit contents. Nothing fancy there.

[dano_____]

So on the topic of the ICE Epic. Looking at the patent drawings, the regulator is situated as the air coming from the top and then going down to go into the air transfer tub after being regulated. It has been a while since I took one apart, but from what I recall there might be a possibility of revising the top portion of the reg to use a Schrader valve like a ccm or bob long reg. There is already a large chamber below that could fit a piston and possibly use the existing spring pack. The reg is adjusted from the bottom with the original design and you could use that for the retrofit as well. Patent number is 6520171 for images to look at. This would simplify replacement parts significantly and reduce it to common orings and a common valve.

[DocsMachine]

Thanks for the pics and info, Levi. I'll double-check that when I can dig out my Sydarm and see.

And Dano, I'll definitely have a look. I was, however, given to understand that the Epic regulator worked fine, it's just that when that one oddball seal starts to go bad, then the reg doesn't work properly anymore. As I recall from the last one I looked at, I thought there was a way I could fit a standard O-ring in there, but I'd have to design and make a new piece to make it work.

Doc.

[dano_____]

Fair enough. I tried using xrings in place of the energized seals and could never get anything to seal up. Newly machined parts might help. My working epic has no problems with the regulator.

[infamoussmiley]

-Sheridan style poppets like that are brass with a steel shaft and crimped shut. It'd be almost impossible to replace just the seal portion, but the entire part could be reproduced.

An interesting thought, I'll add that one to the list.

Doc.

Hi Doc,

Understood on the limited life span of the VM-68 cup seal. I have the steel shafts. I was looking into make the brass pressings and the seals. Seals themselves need to be like the original.

Best,

Smiley

[DocsMachine]

Understood on the limited life span of the VM-68 cup seal. I have the steel shafts. I was looking into make the brass pressings and the seals. Seals themselves need to be like the original.

-I hadn't considered rebuilding/remanufacturing originals, that's an interesting thought. Yes, making the brass collar and soft seal should be easy.

I have a VM disassembled- one of my own projects, it's been sitting for a while- and dug out the cup seal to see. I don't recall if this thing was leaking or not- it hasn't been assembled in well over a decade- but the seal face wasn't in the greatest shape.



I got a bunch of measurements before I started work, and then tried to turn the OD of the brass to "cut" it off. I got a ways through it, but eventually, even with the very lightest of cuts, it'd just spin on the shaft. I tried driving the rest through with a punch, but the "nail head" on the end shattered.



Not a huge problem, I could still get the relevant measurements and dimensions, and it'd be easy to turn a new brass collar and punch fresh seals.

How many seals do you have or can gather together? I can't really sell a "rebuild kit", as you'd have to have a matching punch and die to crimp it, similar to what I did for the Montneel seals. That'd end up being a $60 or $70 rebuild kit.

But, if you could get together a fair handful of originals, I could rebuild them as a batch- or periodically in batches.

Barring that, I'd also need to turn the posts as well. The shattered head shows the originals were at least somewhat heat-teated... Probably not strictly necessary considering that the cup seals in brass-tube guns are, well, brass...

I'm wondering if we could put together a two-piece cup seal, with just a shaft and machined plastic cup seal, like some of the later 'Cockers, and most stacked-tube blowbacks...

Oh, and on the Dynaflow, I popped the reg piston open and extracted the seal... or rather, what was left of it.



Easy enough to get dimensions from the remnants and the part it came out of, but yeah, the seal in this particular reg was well on it's way to goo-city.

Simple enough to punch, so once I get the proper O-rings in, I can easily put together rebuild kits.

Doc.

[Levi]

The fact that the classic valve kits are available from AGD but the Sydarm kits are not is suggestive that there is something unique going on.

Looks like I'm completely wrong on this. AGD still has the Sydarm kits on their website. They are not in the "GUN PARTS" category with the other rebuild kits, they are in the "LEGACY PARTS" section. Probably not worth messing with as long as they remain available from AGD.