Tubing used in any application needs to fit well inside connectors because if it doesn't, the consequences can be rather bad. These consequences may seem minor at first, but over time, they can lead to tubing or equipment failure. One of the best ways to ensure the tubing you use fits exactly the way you need it to is to use custom plastic tubing. Using materials that are made specifically for your project or equipment may seem unnecessary if you find generic tubing that seems to fit well. But that generic plastic could be off by just enough to really cause problems down the line.
Slightly Too Big: Cracks and Pressure
Plastic is a versatile material, but even the toughest plastic isn't invincible. If the generic tubing you use is just a tad too big, you may end up having to shove the end of the tubing into the connector hard enough to cause some friction-related damage. Remember, you're looking at nanometers of difference here, so the tubing may seem only a bit tight when really it's a bit too big for the opening. The end of the tubing could be compressed by just enough to cause the material to develop microscopic cracks that could lead to failure in extreme conditions.
Another issue is that the slight compression of the tube end would affect not only the exterior of the tube but the interior as well. The opening into the tube would be slightly smaller, and that can increase pressure as liquids and gases travel through the tube. You might not notice a difference at first, but the cumulative effect over time could make a difference in how well or how poorly your equipment performs.
Slightly Too Small: Leaks, Even With Tape and Caulking
Now look at the other possibility: The tubing could be just a tad too small. This would allow leaks to occur, and while you could use plumber's tape or other materials to fill any gaps — even caulking could be an option — over time, those measures could fail. The risk of more leaks is increased because the tubing could move a little too much as vibrations from the rest of the equipment travel through the pipe. Caulking and tape can both give a little, so initially, the vibrations may not be an issue. But as the tape and caulking dry out over time, you could see those vibrations start to rattle the tubing more, leading to breaks in the caulking and gaps in the tape.
You can solve most of these problems by using custom plastic tubing from the start. When that tubing fits well and isn't too big or too small, even by a tiny bit, you'll have less to worry about as you use the equipment that the tubing is a part of. Reach out to a company like Seiler Plastics that provides custom plastic tubing to learn more.