Montneel Design Mega Z help

[DocsMachine]

I was asked not too long about about making a Montneel cup seal... Been meaning to crack one of mine open and give it a look. I haven't had one open in years- for that matter, haven't had one gassed up in years.

Can't imagine they'd be too hard to replicate.

Doc.

[Meleager7]

I was asked not too long about about making a Montneel cup seal... Been meaning to crack one of mine open and give it a look. I haven't had one open in years- for that matter, haven't had one gassed up in years.

Can't imagine they'd be too hard to replicate.

Doc.

Hi Doc, is the sheet of seal material you have liquid co2 friendly?

Actually , that raises the question, what does make certain polymers liquid co2 friendly!??

[DocsMachine]

Hi Doc, is the sheet of seal material you have liquid co2 friendly? Actually , that raises the question, what does make certain polymers liquid co2 friendly!??

-Actually, most urethane/polyurethane seals are CO2 resistant. The issue largely stems from common Neoprene O-rings, which have excellent qualities when used with oils and greases, but are permeable to CO2. The O-ring gets saturated with CO2 and swells, which can jam moving parts. Or, when the pressure is removed, it wants to bubble back out of the O-ring material, which causes it to basically blow out.

As far as a cup seal goes, any decent quality polyurethane, as well as Delrin, Teflon and other rigid plastics, have no problem with CO2.

Doc.

[Brokeass_baller]

Anyone have measurements? I can get some scrap delrin at work, and I have a small hobby lathe in my basement shop. I wouldn't mind taking a stab at a few for the cost of shipping. Won't be quick though. I have to wait until the work machinist needs the delrin for a project. Then I can take his scraps.

Also need pin threads and depth.

[DocsMachine]

Okay, I dug out and dusted off my collection of Montneels... and it would seem I only have one complete valve.

I've had two in-parts Z-1s for a good number of years, I may have taken them in trade for other work. I've been meaning to resurrect them, but with a 100% functional Mega-Z, and 'leventy million other projects, I just never got around to it.

So I cracked open the Mega, for very likely the first time in... well, this century in all probability, and opened up the valve. Here's the cup seal in question, for those curious.



It's a polyurethane O-ring pressed into a groove in the face of a brass disc, and then roll-crimped. The crimp is vital, as it keeps the O-ring in place. I suspect that, from what you fellows have said here, that it's not a simple case of just prying the old goop out, and pressing in a new O-ring. I have a castable polyurethane I could probably inject in there, but I believe the correct fix is to make a new assembly.

The O-rings (which I haven't measured yet) are almost certainly off-the-shelf, so we just need the brass bit. That is easy to fabricate, and I can easily pop off a small run of them, including new O-rings and roll crimping, so you'd get a ready-to-drop-in new cup seal.

If that works for you gents, let me know- not a preorder of course, but tell me how many you'll need. If there's enough demand, I'll set up the CNC and crank a big batch.

Doc.

[Brokeass_baller]

Yeah that's probably more complicated than I can do. Lol. I was thinking they'd be similar to a Spyder or something, with a simple step.

[NONOBLITUS]

Ok so the original OP and I have a trade deal going for the Mega but I would be down for 2 definitely and 4 depending on the cost

[Chappy]

Doc, if you make them I will definitely buy a few as well.

[XEMON]

I can get some scrap delrin at work, and I have a small hobby lathe in my basement shop.

The ones i made out of delrin didnt seal, its a bit too hard. But the 3D printed ones did work perfectly, but it does require to machine the cupseal a bit to fit.

Here is the delrin one:


And the 3D printed:


PS: i do have the Solidworks CAD of the brass cup i reverse-engineer if there is interest.

[Meleager7]

I'd be down to buy 3 cup seals, and I'd buy 3 rear bumpers if you have any left

[NONOBLITUS]

Oh yes bumpers also.

[DocsMachine]

No worries on the bumpers. I have a small fistful on hand, and the molds and materials to make more.

Doc.

[Chuck E Ducky]

I can’t wait to get shot by this thing. Glad it’s going to a good home.

[DocsMachine]

Rough prototype to start nailing down some of the specs.



It's close, but not perfect- note that it's too tall.

I also don't have the right O-rings. I have generic Buna-N, and a few soft poly in the right size, but the center O-ring at least needs to be fairly stiff. I'll order some, though the holidays will slow that up a bit.

Once I have some proper O-rings in, I can nail down the dimensions for the brass bit a little better, run a couple test pieces, try 'em out, and then crank a batch.

Doc.

[DocsMachine]

Quick Q: Would you gents just be interested in a cup seal, or a full rebuild kit? That is, all the O-rings, the cup seal, a fresh bumper, etc.

I could offer both, I suppose...

Doc.

[NONOBLITUS]

I keep hitting the like button over and over. Yes please to everything !!

[Meleager7]

I'd like rebuild kits, cheers,

[Chuck E Ducky]

This makes the BLITUS Happy!

[Chappy]

I came to MCB so many years ago looking for Montneel cupseals. It’s like the circle of life or some sh-t….

[Brokeass_baller]

I don't even own a Montneel, but I'll buy a cup seal or two just in case. Lol. I've always liked them, maybe one day I'll get one.