Time to give the motors a kick in the guts.

[cat man do]

Originally Posted by never monday

So,
Cat Man, how about pulling out thoes old impellers? we'll see if they've changed in a year of Vaseline?

OK, Well it took me a while to find them as I had put them in a safe spot.

Got 'em out and cleaned 'em up , bent blades back to see if any cracks at the bottom and they appear to be as ........................ good as the day I took 'em out.

Dave

[never monday]

Have they swollen?

[cat man do]

They certainly dont appear to have Pat, they did just have a light coating of Vaseline though. Don't know if that would make any difference.

Dave

[never monday]

well drat, I was hoping I was right.

[cat man do]

sorry mate, better luck next time

[yotphix]

It is pretty common practice for engineers to use vaseline as an impeller lube/protectant. Not really sure if it is necessary but I have never seen any harm come from it either. An instructor at a major maritime school in Ft.Lauderdale who has 40 years as an engineer in commercial shipping recommended it to me. (Haven't tried it yet though)

[never monday]

I know it's common practice. But does that make it right? Volvo ships a tube of KY with their impellers. So does Westerbeke on a few models.

[hellosailor]

Lubricants on "rubber" can be tricky. There are some general issues about petroleum products /vs/ synthetics for use on "natural" rubbers and plastics /vs/ ones made from petroleum products. But if I had to "pickle" a rubber part, I'd just dust it with talc. Plain talc apparently seals the surface well enough to stop oxidation in real rubber parts, and doesn't do them any harm. Learned that from a genuine USN-WW2-issue Frogman, and I've got some rubber straps and things going on 20+ years old with no drying and cracking that way.
Armorall also seems to do a good job, but there are issues about that being TOO good and making things release in some applications. Like, glued seams on inflatables.

[Sonosailor]

In 2003, I had put vaseline all over both of my used impellers in October, when putting Cat Tales away. In the spring, I reassembled the pumps and enjoyed the boat in fresh water in Canada all summer. Then I sailed 2300 miles or so to Trinidad. When I had the boat hauled, one impeller was missing a vane, and the other had a slightly torn vane. I found the missing vane on the heat exchanger.

So, was it the vaseline or the use?

Okay, the question is tongue in cheek. The impeller provided a few years of service, so I can't believe the vaseline did any damage.

[yotphix]

No, it being common practice doesn't make it right. Point is simply that If it is regularly done without ill effect it can't be all that terrible. Generally speaking, UV light and Ozone (such as from gasoline motor exaust are the only two things that I have seen dramatically degrade rubber. Other than harsh solvents of course.

[hellosailor]

OK, send the children out of the room, I'm going to use an adult word here. Try taking a rubber or latex exam glove, not a kitchen chemical glove, or better yet, taking any common latex condom, and putting vaseline or any petrochemical on it. The thinner the rubber is (i.e. the condom) the sooner it will burst simply from having the petro grease on it.

Now, put some Vaseline on a car tire. Funny thing, no problem.

The thing is, all of these products are "rubber" from the common view. But they are as radically different as teak wood versus balsa wood. All wood is not the same, all rubber is not the same. Does any one of us have ANY idea what rubber compound our impellers really are made from? Is it rubber, or plastic? Vulcanized or not? Additives or not?

Don't ask me.<G>

I think a good point has been made, that SOME rubber can rot apart after SOME contact with petrochemicals, and it is simply safer not to let the two get together. I remember some time ago a company was making impellers from a blue silicone plastic instead, blue so you could tell they were different, silicone for durability. I have no idea if they are still available or how good they were.

[Alan Wheeler]

The rule of thumb is, You don't use petroleum products on rubbers and you don't use silicon products on silicons. The issue with rubber is that it is made with petroleum products. No not the rubber itself, that's from a tree, but the "emulsion" that makes the finished product is made from petroleum products. Oils or anything that has petroleum bases in it, will eventually deteriorate the rubber. Just how the rubber part is affected depends on it's make up. It may swell, it may go brittle, it may go sticky, but it will deteriorate. The impellors designed to come in contact with oils are Nitrile. A very different material.