I ordered some 1/4" stainless compression fittings for my temp probes, but they did not include o-rings. I'm assuming they are size -010, but can someone please confirm prior to me placing an order.
Squeeky
Squeeky
O-ring size for 1/4" temp probe compressions
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tnlandsailor
Well-Known Member
Typically, compression fittings do not seal with O-rings. They are a metal to metal seal using the cone shaped ferrules that mechanically deform around tubing or any round metal object inserted through them when the cap is tightened down. The first time you screw the cap down, the ferrule will mechanically "lock" to the tubing/shaft. When you unscrew the cap, the ferrule will be locked in place around the OD of the tube/shaft.
You don't necessarily have to tighten the cap down to the point of deformation of the ferrule in order to get a perfect seal. In a brewing scenario, you aren't dealing with any appreciable pressure, so sometimes you can just tighten down the cap only slightly and get a seal, but not deform the ferrule. This is what I do for the thermocouple on my HERMS. The thermocouple is 1/8" OD and slides down into a stainless steel compression fitting with a stainless steel ferrule inside. I slide the thermocouple down into the fitting, and just tighten the cap with my fingers and this is enough to get a seal. After I'm done, I can unscrew the cap and slide the thermocouple out. You might want to try and see if you can seal your temperature probe this way prior to spending money on O-rings.
I have seen people remove the ferrule and use a couple of O-rings stacked on top of each other to seal a tube/shaft. This will also work in a brewing scenario, again because there isn't any real pressure to deal with. A -010 O-ring has an ID of 0.240" which sounds about right.
You don't necessarily have to tighten the cap down to the point of deformation of the ferrule in order to get a perfect seal. In a brewing scenario, you aren't dealing with any appreciable pressure, so sometimes you can just tighten down the cap only slightly and get a seal, but not deform the ferrule. This is what I do for the thermocouple on my HERMS. The thermocouple is 1/8" OD and slides down into a stainless steel compression fitting with a stainless steel ferrule inside. I slide the thermocouple down into the fitting, and just tighten the cap with my fingers and this is enough to get a seal. After I'm done, I can unscrew the cap and slide the thermocouple out. You might want to try and see if you can seal your temperature probe this way prior to spending money on O-rings.
I have seen people remove the ferrule and use a couple of O-rings stacked on top of each other to seal a tube/shaft. This will also work in a brewing scenario, again because there isn't any real pressure to deal with. A -010 O-ring has an ID of 0.240" which sounds about right.
Did anyone ever figure out the proper size O ring? Thanks, castermmt
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