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What are the Reasons Air Hose Quick Connects Fail?

05/11/2018 9:33 AM

New or old / inexpensive or costly I find that air hose fittings have compatibility issues and leak uncontrollably at some point.

I have some fittings from the same source that work with one coupling, but not the other? Nothing seems different in any way from one connection to the other, but some air hose will work with one manifold connection, but not the other.

If it were merely hissing involved I could (almost) understand,but the number of same type fittings that won't even connect is baffling.

I use my compressors and hoses all the time.. Years ago I just assumed I was doing something wrong, or was lacking some crucial knowledge, but I've been down this road so many times and I'm shtumped.

Question?

Does anybody have a favorite brand that they have worked with and trust? The hoses are not the issue.. just the fittings.

My bucket of fittings runneth over, but I'd replace them all to stop all the unnecessary hissing.

See below..

One hose with connect on the left side, but not the right?!?!

similar situation with one like this..

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#1

Re: What are the Reasons Air Hose Quick Connects Fail?

05/11/2018 10:13 AM

Rebuild 'em, need to clean it out, maybe replace spring and rubber washer and/or add o-ring...

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#2
In reply to #1

Re: What are the Reasons Air Hose Quick Connects Fail?

05/11/2018 11:40 AM

thanks SE.. That's informative for sure. I'm curious to take apart the ones that bottom out with one connector but work fine in another from the same source.

What gets me is the number of out of the box failures and compatibility issues on something so common.

I'll post my findings another day.

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#3
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/11/2018 12:03 PM
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#5
In reply to #3

Re: What are the Reasons Air Hose Quick Connects Fail?

05/11/2018 2:23 PM

GA

The baffling part of this is why there are so many different types of air hose quick connects? I suspect there are many reasons but they fall into two main types. First, there will be the engineering reason where the quick connect is optimized for some engineered aspect. This could be flow rate, flow direction, pressure retention, pressure range, air impurities, etc. Second, liability and customer loyalty issues.

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#6
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/11/2018 5:36 PM

I have two styles. Most are Milton, but some are Type T, which I found is also called Camel.

A male type-T will mate with a female of either T or Milton, but leaks if mated with the Milton. Milton will not mate with a type T.

A third reason for different types may have to do with the "phone charger plug syndrome" of, you have to buy this one for that phone.

Harbor Freight carries both Milton and type T. Interestingly, all Milton's are brass and type T's are chrome or sliverish plated.

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#7
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/12/2018 11:07 AM

One reason for so many types, is to prevent the use of some hoses on a specific system, to avoid cross-contamination. Not all systems supply the same quality/clean air as others. You don't want to mess up a clean/special hose from a dirty/different system or connect a hose used with auto-oilers inline with clean hoses, etc.

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#10
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/14/2018 8:44 AM

For the cost, at least what I buy them for, it is usually just more cost effective to replace them, especially if you have to pay someone (maintenance) to do so.

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#13
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/16/2018 12:41 PM

After dis-assembling both a Milton and a Type-T female coupling, I can tell you that 99% of the wear/leak comes from the rubber gasket, which can easily be turned over to give the connector a second life. That gasket seals both the male connector (to prevent the leaks we are discussing) and the two main parts of the female coupling. They do not use tapered threads and can be reassembled by hand and not leak.

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#14
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/16/2018 2:33 PM

You are probably accurate and correct. I wouldn't know as I have always just replaced.

My point is to see what the most cost effective way is. Is it cheaper to buy a new one at say $3.50, or pay some one to do it. If the labor cost to dismantle/fix/reassemble exceeds 1/2 the cost of a new one (a "rule of thumb" I adopted a long time ago), I would just replace it. So you can figure out what the labor cost is based on the wage/benefit/burden cost per minute and compare. In my shop that is about 2 1/2 minutes, and you as well as I know, that if you are paying someone to do it, it will take longer.

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#15
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/16/2018 2:47 PM

Your metric for determining repair or replace is very common and frequently a very shortsighted and wasteful metric to maintain a machine. Replacing a failed non-maintenance part instead of repairing it can mask a bigger problem slowly becoming a disaster.

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#16
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/16/2018 3:01 PM

Agreed that each and every item must be looked at on it's own merits/costs. There are times when just replacing one thing would not be the proper approach. You have to establish how that one part may affect other parts and just how many parts in the "chain" should be inspected and replaced or replaced outright.

The OP only has a few "connecting" items:

1- the male coupling

2 - the hoses and clamps used on the coupling

3 - the part or pipe the coupling is attached to.

This one is pretty straight forward. Others are much more complicated.

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#17
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/16/2018 3:55 PM

I believe that you are the first to mention working in a facility that has a maintenance department to perform such a trivial task.

I believe that OP, and most other users, just do it themselves and replace instead of repair.

Union shops are much different and less productive since simple R&R is forbidden. Fresh off the farm, I once got "talked to" for tack welding the pads on the feet of a cherry picker for shipment, instead of calling, and waiting, for the union welder to do it.

It takes about 5 minutes to unscrew, turn the rubber washer over, and put it back together. Probably less time than replacing as no pipe tape is required.

In a large factory, with a maintenance crew, you are right.

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#18
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/16/2018 5:20 PM

Maybe. But being able to fix it yourself in the field is priceless.

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#19
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/17/2018 8:14 AM

I agree. I still enjoy the hands on portion, but,, there is only so much time in the day.

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#4

Re: What are the Reasons Air Hose Quick Connects Fail?

05/11/2018 12:27 PM

Working in a paint facility, I buy a lot of air fittings. I get them from Grainger or McMaster Carr.

For the most part, they last unless they get nicked up.

There is one brand that seems to hold up very well and that is Speedaire.

Just my 2 cents worth.

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#12
In reply to #4

Re: What are the Reasons Air Hose Quick Connects Fail?

05/14/2018 5:44 PM

I get the best pricing from Fastenal. Amflo brand.

if you are looking for 1/4" size here are the numbers.

FASTENAL PART # DESCRIPTION

430117AIR COUPLER - 1/4 NPT FEMALE
430120AIR COUPLER - 1/4 NPT MALE - AMFLO C21
430017AIR PLUG - 1/4 NPT FEMALE - AMFLO CP20
430020AIR PLUG - 1/4 NPT MALE
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#8

Re: What are the Reasons Air Hose Quick Connects Fail?

05/12/2018 2:56 PM

If you look into the inside of the female QD, you see this: That slotted thingy in the center must be some type of adjuster, else why the slot?

Well, not so. There's nothing adjustable inside. It's just a slot that lets the air flow into the tool, I think.

So, if we cut two more slots in that part, how much better would the air flow be?

I can't think of a simple way to measure the air flow to try this. Maybe fill a small tank and measure the time to drain the tank with standard and then with 3 slots, instead of the one.

Is it worth trying?

Type-T connectors are constructed differently, with two springs and a less obvious disassembly, where the very end of the barrel is grasped with the vice grips.

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#9

Re: What are the Reasons Air Hose Quick Connects Fail?

05/14/2018 8:42 AM

You do have to watch what you buy. There are severel different styles available, none of which are interchangeable. As for the reason they fail/leak, the female have mechanical parts in them and the do wear out with use.

I use the different styles to differentiate between uses. For example, I have an application where I only want 20 psig, so I use a different style so that other quick connects will not plug in, only the hoses that have the mating unit.

As for a favourite brand, I have found that there is not much difference in quality from the cheapest knock offs to the most expensive and there is a "standard" for these, what it is I don't know, but between brands the same styles will interchange.

You just have to "standardize" on what works best for you and, if you do not purchase them yourself,,, make sure that whomever does do the buying is aware of what you really want as there are price differences between styles and they may buy the cheapest that "look like what you want" not knowing that they will not work in your application.

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#11

Re: What are the Reasons Air Hose Quick Connects Fail?

05/14/2018 5:00 PM

Great replies. I still have to investigate a mysterious coupling connection.

With much new knowledge

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#20

Re: What are the Reasons Air Hose Quick Connects Fail?

05/18/2018 1:49 PM

There are at least 3 different types of connectors, most commonly known as industrial, automotive and universal. All 3 are available in brass or various alloys. There are also high flow versions of each style. They all use a seal or o-ring which will eventually leak .

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#21
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Re: What are the Reasons Air Hose Quick Connects Fail?

05/18/2018 2:38 PM

Thanks.

This subject has been well covered in previous threads.

Stick around for more fun.

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