j_man

I have an Aquamist kit and recently after few years of use the pressure gauge started going bad. Actually the pressure gauge was not part of the original kit, but some cheap DIY creation of the USA reseller who has tapped it and added some adapter to connect to the 4 mm tubing from the Aquamist kit.

Now I am getting some better gauge (1-1/2", silicone filled, shock resistant) from McMaster (part # 9780T115 ) and like most similar sized gauges the connection at the back is 1/8 NPT male. I am also getting a 1/8 NPT sized pulsation-damping snubber (part # 3820K11 ) to make gauge's life easier.

Now I need a fitting to connect the 4mm Aquamist tubing to the 1/8 NPT male thread of the snubber.

At McMaster the NPT ones are matched for inch size tubing only (no NPT to metric tubing)

The closest to 4 mm inch sized tubing is 5/32" ( == 3.96875 mm)
This should work, right?

At the McMaster web site I typed "push-to connect fitting" to start the wizard, chose adapter, female pipe, 5/32" tubing, 1/8 NPT.

Then it gives me two options:


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Part Number: 5779K125

1-9 Each $4.37 Each

Tube Fitting Shape: Adapter
Adapter Type: Female Pipe Adapter
Material: Brass
Finish: Nickel-Plated
Grasping Ring Material: Stainless Steel
O-Ring Material: Buna-N (Nitrile)
Release Ring Material: Polypropylene
Release Ring Color: Black
Thread Material Nickel-Plated: Brass
System of Measurement: Inch
For Tube Outside Diameter: 5/32"
Pipe Connection: NPT
Pipe Size: 1/8"
Maximum Pressure: 290 psi @ 70° F
Vacuum Rating: 28" Hg @ 70° F
Operating Temperature Range: -4° F to 175° F
For Tubing Type: Nylon, Polyethylene, Polyurethane
For Tubing with Hardness: Nylon: Shore D 50 and D 70, Polyethylene: Shore D 44, Polyurethane: Shore A 95
For Use With: Air
Sterilize With: Not Rated
Specifications: Met International Organization for Standardization (ISO)
ISO Specification: ISO 14743
WARNING
McMaster-Carr does not guarantee chemical compatibility because many variables can affect the tubing and tube fittings. Ultimately, the consumer must determine chemical compatibility based on the conditions in which the product is being used.
Compatible Item(s)
Choose-a-Color Covers (5779K792) snap over the release ring for color-coding.


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Part Number: 5111K664 $3.98 Each
Tube Fitting Shape: Adapter
Adapter Type: Female Pipe Adapter
Material: Brass
Finish: Plain
Grasping Ring Material: Acetal
O-Ring Material: Buna-N (Nitrile)
Release Ring Material: Acetal
Thread Material: Brass
System of Measurement: Inch
For Tube Outside Diameter: 5/32"
Pipe Connection: NPT
Pipe Size: 1/8"
Maximum Pressure: 145 psi @ 72° F
Vacuum Rating: 29.5" Hg @ 72° F
Operating Temperature Range: 32° F to 104° F
For Tubing Type: Nylon, Polyurethane
For Tubing with Hardness Polyurethane: Shore A 88-97
For Use With: Air, Water
Sterilize With: Not Rated
Specifications Met: Not Rated
WARNING
McMaster-Carr does not guarantee chemical compatibility because many variables can affect the tubing and tube fittings. Ultimately, the consumer must determine chemical compatibility based on the conditions in which the product is being used.

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So, the first one has nice temperature and pressure ranges, but the site says it is for air use.

The second one is for air & water use but temperature and pressure ranges are not that good.


I am thinking about getting the first one. Do you think it will resist water/methanol mix? I will try to leave some air pocket in the tubing, so there is no water/methanol in direct contact with the gauge/fittings, but there will still be methanol/air vapor.

Is anyone using McMaster push-to-connect fittings in their kits? Any experience with these?

magnamx-5

iTrader: (7)

I would try the first one. I doubt it will leak and the buna should hold up to methanol mixes just fine. IDK about your sizing dillema though. This is why i am glad to run 1/4 inch normal stuff GL