I have been using the Legacy brand Hi Flow airline fittings for several years now and have never had an issue.

Lately I have been giving my DA sander a good workout on my jetboat project and it seems to be eating up the male airline fittings. After using the DA for several hours, when I go to remove the quick connect I can barely get it out of the female fitting.

At first I thought it was because I now use a dust extractor system (which I LOVE) and thought that it might be putting a slight bind on the connector. I then changed out the male fittings on my 6" and 3" DAs to a couple of swivel fittings that I had laying around.

The other day, I used the 6" for several hours and I almost couldn't get the hose disconnected from the tool.

You can see the black marks around the one male swivel fitting, the fixed fittings that I previously chucked had the same thing. The first photo is my 6" DA which got a lot of (one day) use, the second is my 3" DA. Both fittings were brand new.

And it isn't the female fittings as my air gun works fine, easy on, easy off the same female fittings.

I am thinking of trying to add a small length whip hose at my DAs to see if that would help.

* Any idea of what's going on?

OldFatBald wrote:And it isn't the female fittings as my air gun works fine, easy on, easy off the same female fittings.

Humour me. Try changing one of the female fittings and then give the system a solid workout, with a new or cleaned up male. If the markings come back then I'm wrong, but, if they don't, then it's wear in the female side that's allowing a tiny amount of movement that's then generating heat through vibration.

Only a hypothesis at the moment, because I use Nitto air fittings, but when I think of problems I've had they've always been on the female side, even though the male fittings get thrown and dragged across the floor, worn and damaged. Movement induced heat would also explain why the joints are difficult to take apart, with the male swelling. Once disconnected for a while, are those male fittings then easier to reconnect to the females? What about to a different female? Immediately after use or after cooling off?


Totally unrelated to your problem (or maybe not) the opportunities for double entendre here are rife. How long before someone drags this thread into the gutter?

NFT5 wrote:

OldFatBald wrote:And it isn't the female fittings as my air gun works fine, easy on, easy off the same female fittings.

...Try changing one of the female fittings and then give the system a solid workout, with a new or cleaned up male. If the markings come back then I'm wrong, but, if they don't, then it's wear in the female side that's allowing a tiny amount of movement that's then generating heat through vibration.

Today was a block sanding day so no need for the DA. I did order a couple of long whips that should be here by next weekend.
I am going to try one with a whip and the other with a new male and female connector.

....Once disconnected for a while, are those male fittings then easier to reconnect to the females? What about to a different female? Immediately after use or after cooling off?

Different female fittings have the same issue once the male fitting is shot.

Totally unrelated to your problem (or maybe not) the opportunities for double entendre here are rife. How long before someone drags this thread into the gutter?

Yeah, as I wrote my first post, I had to think about some of my sentences and reword some of my responses...

are those fittings aluminum?