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Fuel Drain (CAV-110)

asw20c

Well Known Member
I'm finally about 99% done with the fuel tank construction and the gorilla snot that goes with it (unless I discover a leak when it has cured long enough for testing), having installed the rear baffle and attach Zees this weekend.

First question: The last step on page 18-08 includes installing the fuel drain (part number CAV-110). When I try screwing it into the mating VA-112 drain flange it only goes in about halfway. Just by the look of it I expected it to thread all the way in until it bottoms out on the socket flats. For those that have finished the tanks, how far in did your drain go?
Second question: How long do you need to wait until leak testing your tanks? All the instructions say is to wait until the snot is cured, but based on my experience, that is subjective. I'm thinking a week may not be long enough, and a month is probably too long.
 
Just by the look of it I expected it to thread all the way in until it bottoms out on the socket flats.

Half is not bad, it would be a problem it it did go to the flats.

At normal temps a good 2-3 weeks is enough to be sure it is cured.
 
That is a NPT thread. Study the available materials for it's properties, features, behaviors and expectations.

Bill's guidance doesn't need my concurrence :).
 
Use a good pipe thread sealant and torque till it's snug, then just a little more. If you over torque the drain you risk splitting the aluminum flange. You might wait however to do the final installation since you may want to calibrate the fuel gauges or flush the tanks and drain in prep for weighing. The plastic pipe thread plugs should give you a good seal if you want to do a pressure test.
 
SAF-AIR now makes a stainless version of the CAV-110 (CAV-110SS). I asked ACS to stock it but don't yet see it available.
 
SAF-AIR now makes a stainless version of the CAV-110 (CAV-110SS). I asked ACS to stock it but don't yet see it available.

And here is why one might consider the value of a stainless version after "a little" time in service. The spring is darn near "oxidized" through:
i-RHfsVWP-XL.jpg
 
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