Originally Posted by HopCar
. . . We've been asked for constant tension hose clamps and recently brought them into stock. I've never used them. Do any of you know the correct way to install them? Do you tighten them until the spring is completely compressed?
Do any of you actually use a torque wrench to tighten hose clamps? How do you judge when your clamp is tight enough?
T-bolts clamps versions that are commonly available to the marine
world are like the one shown below from AWAB and others. T-bolts are pretty much for situations where you need "extreme" tightness like exhaust
hoses or other hoses that have a very hard wall.
- - I would not recommend the "spring" version for marine
use. Springs have a habit of corroding or breaking and you cannot get a good "feel" for how tight the clamp is around the hose. There is a much higher "worry factor" in clamping marine hoses as in if the clamp fails the vessel can sink. Trucks and cars don't have that problem.
- - To use you have to back off the self-locking nut or bolt until it comes completely out of the nut. Then you carefully spread the clamp ring to fit over the hose. Finally re-insert the bolt into the self-locking nut and start to tighten it down.
- - It is advisable to stop and ensure the band of the clamp is indeed laying flat on the hose. It is not uncommon for the whole clamp to be "cocked" or tilted on the hose and this will cut into the hose eventually. Also the t-bolt needs to be sized so that the "tongue" closes the circle. T-bolts have a much smaller range of hose sizes than the normal marine hose clamp.
- - Tightening is a judgement matter based on the hose around which the clamp is tightened. For hard hoses like exhaust
you tighten down to it becomes very difficult to tighten anymore for fear of stripping the bolt threads (I call this "two grunt" tight). But care is also needed with exhaust hose "with wire" to keep from cutting the hose by squeezing the wire too much.
- - For soft hoses like blue silicon you have to be very careful as the clamp can squeeze the hose to point where the hose starts to be cut. For blue silicon I do not use T-bolt clamps but instead the standard AWAB "indented" clamps.