Do you use torque wrench on heat exchanger clamps?

[Q Xopa]

Originally Posted by Pete7

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

Sounds fair. My instructor used a match stick, but sounds like soap works too. Another thing Ive learned today.

[Q Xopa]

Originally Posted by 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

Yes I guess Im showing my age talking about match sticks. Youre right I like the Laser pointer Thermometer idea much better.

[er9]

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).

good advice thank you. i completely sanded and am priming/painting the entire heat exchanger and have wire brushed all the hose barbs back to a clean finish with no crud. i was able to get the two barbs i bent back to 95% their original shape. i will keep a close eye on them after i re-install them to make sure there are no leaks.

[er9]

Originally Posted by 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?

i probably made them sound more fragile than they actually are. they are at least .05-.06 thick brass or copper. i'm not sure exactly what metal the barbs are but they look to be the same copper color as the heat exchanger.

when i was removing the old stuck on hoses (while the heat exchanger was still attached to th engine) i tried removing them by sticking a screw driver between the barb and the hose. i had no idea heat exchangers were made from soft copper. of course while trying to pry the hose off i bent/indented the end of a couple of barbs. not smart but now i know...

the distortion was near the ends of the barbs so i stuck a piece of plexi rod that was the same o.d. as the i.d. of the barb and tapped the plexi rod in lightly with a wood block. worked like a charm...mostly...they look reasonably round now....

[er9]

Originally Posted by 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

check!