Do you use torque wrench on heat exchanger clamps?

[er9]

taking the old hoses off i slightly bent the thin copper hose barbs. i fixed them but i dont want to crush them installing new hoses and clamps. i use a socket wrench on the clamps not a screw driver. do you torque them so you dont crush the thin copper or is it a non-issue?

[s/v Jedi]

Originally Posted by er9

taking the old hoses off i slightly bent the thin copper hose barbs. i fixed them but i dont want to crush them installing new hoses and clamps. i use a socket wrench on the clamps not a screw driver. do you torque them so you dont crush the thin copper or is it a non-issue?

I use a nut driver so that you get a good grip on the screw but you only put the same force on it as with a screwdriver.

[er9]

thanks good to know...i probably have been overdoing some of them with the wrench.

[thinwater]

Having spent a career in refineries and chemical plants, I can tell you avoiding leaks is FAR more about making sure the mating surfaces and hose barbs are clean and not distorted or damaged, the fit is proper, and that there are no side loads, than over tightening. You should not need to strain on the nuts at all. Just snug. Two clamps, screws opposed, and properly positioned on the barb (not overlapping the ends, between grooves if practical).

[jmschmidt]

Jedi has it right but I'm concerned about the thin copper hose barbs. My are pretty beefy, no way could I damage them with any kind of a hand wrench. The fact that they are so thin that you damaged them with a hose clamp, the screw of which should have stripped out first, is scary. And by beating it back into shape is also scary. They may have been weakened. Are they replaceable with heaver duty fittings?

[s/v Jedi]

If you can take the copper barb fitting off then you can anneal it: heat it to glowing red, then dump in room temperature water. This realigns the molecules so that any work hardening is fixed.

[Q Xopa]

Originally Posted by s/v Jedi

If you can take the copper barb fitting off then you can anneal it: heat it to glowing red, then dump in room temperature water. This realigns the molecules so that any work hardening is fixed.

Heating to anneal is good advice. However I would just let it air cool slowly/ naturaly. If you quench it in water it tends to 'case harden'.

[RaymondR]

The problem with the worm type hose clamps is they provide a very uneven circumferential clamping force and tend to drag the hose around and bunch it where the strap enters the screw holder generating a crushing load on thin walled barbs. If it's a big enough hose you can end couple two or more clamps which allows a more even tightening.

[Jim Cate]

Originally Posted by Q Xopa

Heating to anneal is good advice. However I would just let it air cool slowly/ naturaly. If you quench it in water it tends to 'case harden'.

Copper is an odd duck metallurgically, for it can be annealed by either quenching or slow cooling. I was shown this in an earlier thread on the subject, and was pretty surprised at the facts!

Jim

[GILow]

Originally Posted by thinwater

Having spent a career in refineries and chemical plants, I can tell you avoiding leaks is FAR more about making sure the mating surfaces and hose barbs are clean and not distorted or damaged, the fit is proper, and that there are no side loads, than over tightening. You should not need to strain on the nuts at all. Just snug. Two clamps, screws opposed, and properly positioned on the barb (not overlapping the ends, between grooves if practical).

Absolutely true. And how I wish I had NOT taken so long to learn this.

[Q Xopa]

Originally Posted by Jim Cate

Copper is an odd duck metallurgically, for it can be annealed by either quenching or slow cooling. I was shown this in an earlier thread on the subject, and was pretty surprised at the facts!

Jim

Ah ok, today hasnt been a waste for me as I have learnt something new.

By the way this same heating up cherry red copper trick also works well for the solid copper sealing washers that often go under some banjo pipe unions and plugs.

[Q Xopa]

Originally Posted by Q Xopa

Ah ok, today hasnt been a waste for me as I have learnt something new.

By the way this same heating up cherry red copper trick also works well for the solid copper sealing washers that often go under some banjo pipe unions and plugs.

This annealing/ softening is also possible on heating Aluminium sealing crush solid washers. However it is more difficult to determine the right amout of heat as it wont go red. If you heat it too much it can just suddenly turn into a molten blob.
As an apprentice I was shown, and use the old rub the back of a match stick over the surface trick. When it leaves a brown lightly burnt line its good.

[a64pilot]

On the hose thing, it’s common practice to tighten most clamps on aircraft exhausts, then retorque after a heat cycle or two as things do move around slightly and loosen.
So tighten not too much, but come back later and check that they are still good and snug

[Pete7]

Originally Posted by Q Xopa

This annealing/ softening is also possible on heating Aluminium sealing crush solid washers. However it is more difficult to determine the right amout of heat as it wont go red. If you heat it too much it can just suddenly turn into a molten blob.
As an apprentice I was shown, and use the old rub the back of a match stick over the surface trick. When it leaves a brown lightly burnt line its good.

I thought for aluminium you rubbed soap on it and then heated. When the soap goes black then its hot enough. Admittedly it was 40 years ago so might be wrong.

Pete

[s/v Jedi]

Apart for 1 year in school where I even got metal working class, my background is microelectronics design and engineering. Everything I know about mechanical and civil engineering is from videos, books, websites and playing with my boat :-)

But I'm still checking out everything I can find today and much of the new things I learn is improvements in tools. For the checking of temperature, you now use a laser-IR temperature gun, not the back of a match or soap etc :-) I have since bought a bunch of those and find new applications for them almost every day. I use it to check the temperature of yogurt while incubating it but also for the breaker panel, diesel injectors etc. Checking aluminium parts during annealing is now on the list as well :-)

About the quenching: yes, this only works for copper but as you can use the part immediately instead of waiting for natural air cool down, everybody quenches it. It's also cleans the part although I still clean it more because I'm crazy