Priming Tubes


Sometimes the bear gets you. Sometimes you get the bear. Today, I got the bear.

Almost every airplane has a tube or weldment, and often they need to be primed inside. If you’re like me, you struggle with sealing the end and, inevitably, more primer ends up on the floor than inside the tube. I’ve tried all sorts of plugs and tape with questionable results. My shop floor is evidence to my failure.

Most of us have a box of nitrile gloves. Turns out they work for more than keeping your hands clean. Cut the fingers off a glove or two. Choose the fingers that fit nice and snug. Pinky fingers work for smaller tubes. Thumbs work for large tubes. For this job, I used the middle fingers.

When priming the inside of weldments, fingers from nitrile gloves are a great way to seal the ends of the tubes.

The gloves are usually dusted inside with powder to make them slide on easier. The powder will allow the finger to slide off. Slip a finger over the tube but make sure the outside surface of the glove is the side against the surface of the tube.

Place the gloved end of the tube in a bucket. No reason to tempt fate. Pour in the primer, then slip another glove finger over the open end. Remember, inside out.

Slosh the primer back and forth while rotating the pipe. A minute or two, or at least two rotations, is plenty. Stand it on end over the bucket again. Slide the top finger off and pour the contents into a paint cup. Stand the pipe open end down in a bucket to catch the remaining primer and slip the finger off the sealed end.

No mess! Wish I had thought of this one several messes ago.


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