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WTB Clippard MJQC-B4B4

Posted: Tue Nov 13, 2018 4:54 pm
by Dale_F
This part has been discontinued by Clippard and I have used them for my brake lines. I know it is a long shot, but would really like to hear if someone has some they could spare.

Please send me a PM with quantity and asking price.
Thanks.
Dale.

Re: WTB Clippard MJQC-B4B4

Posted: Tue Nov 13, 2018 5:00 pm
by Berkman
isn't this part used by most that have a clippard based air system ?

Re: WTB Clippard MJQC-B4B4

Posted: Tue Nov 13, 2018 5:12 pm
by FLtenwheeler
The bulkhead fittings are still available.

Tim

Re: WTB Clippard MJQC-B4B4

Posted: Tue Nov 13, 2018 6:50 pm
by Berkman
But isn't this the part # that most systems use as the " gladhands" ?

Re: WTB Clippard MJQC-B4B4

Posted: Tue Nov 13, 2018 6:58 pm
by Dale_F
Tim - from everything I can find, Clippard is saying the entire MJQC line is discontinued. Do you have a supplier for the MJQC bulkheads? It would probably be a MJQC-PBB4, which would work. I Just need something in that same MJQC line.

These fittings have a valve and a cap. The valve is used on the back of the car. When the cap line connects, the valve opens. They are higher volume than all other mini clippard connections and I have used them on all my trains for years. Clippard just discontinued them due to low sales. I have been searching the world trying to find some hidden quantity that some vendor still had in stock, but so far with no luck.

Image

Re: WTB Clippard MJQC-B4B4

Posted: Tue Nov 13, 2018 7:47 pm
by Berkman
Would these work https://www.clippard.com/part/MQC-3 ?

Whats the difference between the MJQC and MQC series?

Re: WTB Clippard MJQC-B4B4

Posted: Tue Nov 13, 2018 11:55 pm
by Harlock
Berkman wrote:
Tue Nov 13, 2018 7:47 pm
Would these work https://www.clippard.com/part/MQC-3 ?

Whats the difference between the MJQC and MQC series?
One's brass and the other appears to be stainless. I have only ever used the brass ones and they still appear to be available. The MQC-3 is the heart of my brass setup.

Here is a detailed list of the part numbers I use, and all still seem to be there.
http://www.chaski.org/homemachinist/vie ... 60#p284360

by the way, I hadn't run the loco or the cars in 7 months earlier this year. I have a small air resovoir on the engineer's car directly behind the tender, so I can have brakes when I leave the boxcar in the yard and go back to the bays. That resovoir and two fittings on either side of the car held 50 PSI for 7 months. Amazing stuff, the clippard valves and connectors.

Best,

-Mike

Re: WTB Clippard MJQC-B4B4

Posted: Wed Nov 14, 2018 11:33 am
by Dale_F
Thanks Mike. I have always used the MJQC series because of the flexibility (1/8" tube connectors) and the high flow rate (14 scfm @ 100 psig ). Being able to get air pressure to the back of the train, and then release it quickly was important to me.

The MQC-3 series, while cheaper, only move less than 6 scfm at 100psi. I made the decision based on connection flexibility and volume. I appreciate the info, but am deep vested in the MJQC series. To switch now would mean changing 4 locomotives and a whole bunch of cars over to the new connector type. I am not ready to do that yet, which leads me back to...

Does anyone out there have any of these MJQC's? Is anyone else faced with this problem? And I guess I could open this up to what quick connects are you using between cars? Mike has already brought up the Clippard MQC-3 series, but I have already used those and dismissed them because of the flow rate and large size (unless panel mounted).

Thanks.
Dale

Re: WTB Clippard MJQC-B4B4

Posted: Wed Nov 14, 2018 1:24 pm
by ccvstmr
Whats the difference between the MJQC and MQC series?
The MJ's are jumbo sized quick connectors. Already pointed out the pass-thru volume was more for the jumbo's than the normal (MQC) quick connectors. While the QC's do present a restriction in the air line (like most quick connectors), if you're sticking with the 1/4" OD x 1/8" ID...don't think that restriction is going to be noticeable for our train operations...not unless you're running a 200+ foot long train. Then again, welcome to realistic train operation...where the front of the train slows down before the back end. Passenger trains (Amtrak) use electro-pneumatic braking so the train brakes on the new equipment (post Heritage Fleet) apply equally along the length of the train.

Don't believe Clippard does any of their QC's in stainless. Believe the choices are brass or what looks like stainless, which is nickel-plated...with nickel-plated hardware usually being a special order item.

Looking for MJQC's? Do an on-line search. Might find a supplier somewhere with new-old-stock on the shelf. But if this is your standard air brake quick connector...suggest you grab anything and everything you can. Sounds like Clippard did not have a large enough demand to maintain manufacturing the larger sized QC's. Carl B.

Re: WTB Clippard MJQC-B4B4

Posted: Wed Nov 14, 2018 2:10 pm
by Harlock
This is just my own experience, but I haven't had any problems with insufficient air flow with the smaller connectors. I am using 7/8" dia cylinders on 2 1/2" scale trucks, and they really don't need a lot of air. The system can pressurize very quickly. I am thinking I have 8 braking trucks plus a cylinder on the rear loco drivers all on the same connection, and the train will stop very quickly even on a good down grade...compressor regulator is set at 65 PSI, most braking applications are between 10 - 15 PSI for heading downhill. Only if I want to stop fast do I dump the air in at higher pressures. I am using a Jack Bodenmann brake valve. Train with loco but without riders is probably 1,800 lbs.

Re: WTB Clippard MJQC-B4B4

Posted: Wed Nov 14, 2018 7:34 pm
by BigDumbDinosaur
ccvstmr wrote:
Wed Nov 14, 2018 1:24 pm
The MJ's are jumbo sized quick connectors...While the QC's do present a restriction in the air line (like most quick connectors), if you're sticking with the 1/4" OD x 1/8" ID...don't think that restriction is going to be noticeable for our train operations...not unless you're running a 200+ foot long train. Then again, welcome to realistic train operation...where the front of the train slows down before the back end.
Yep! Brake response on the full-sized stuff is actually rather slow. Even if the engineer dynamites the brakes the train will experience some run-in due to propagation delay in the brake pipe. Such a sudden brake pipe pressure change will propagate at approximately the speed of sound. For estimation purposes, it is assumed that it will take about 50 milliseconds per car for the pressure change to propagate. Using that rule of thumb, the caboose at the end of a 100 car freight train will not apply its brakes until close to five seconds have elapsed following an emergency brake application.

So using the smaller MQC type connectors may be inadvertently resulting in more prototypical operation. :shock:

Re: WTB Clippard MJQC-B4B4

Posted: Wed Nov 14, 2018 10:48 pm
by ccvstmr
Have always found it interesting with people in and out of the hobby...that think the engineer has a big ole brake pedal up there in the loco cab! That would be some braking system to stop long trains!

In our hobby, train brakes usually consist of vacuum, straight air and triple valve. Vacuum is usually produced on demand. Only know of one instance where the tender had a vacuum reservoir. There is still some delay associated with creating a vacuum on-demand. Straight air brakes are pretty much direct acting when using an air reservoir to store pressure. Triple valve air brakes will have a delay between the time a brake reduction is made and the brakes start to set up. Nothing wrong with this. It's the nature of the beast.

If brake activation is going to be a problem...then model engineers need to do what they do in the real world. That is...plan ahead! Can't do much about emergency situations. When you gotta stop...YOU GOTTA STOP! If there's any delay in braking no matter what kind of brake system is in use...that delay needs to be incorporated in the train operation.

Some time ago, I considered running 1/8" od x 1/16" id brake tubing from the brake pipe to the brake cylinders on the trucks for this very effect. To build in a slight brake activation delay. Never followed thru with that. Sometimes let others run the loco...best they have direct acting brakes to prevent stopping problems. S'pose a delay could be accomplished by using a flow control valve right after the brake stand. For now, no sense re-engineering things until they don't work at all! Carl B.