Grease for plastic

[vavet]

I have a few of the Nelson Raintrain traveling sprinklers. They are pretty handy but they have a few flaws.
The one I ran this morning turned extremely slowly after running for a while. I cleaned out the inlet screen, which will probably help, but I'm also noticing a lot of torque is required to turn the T-fitting that the sprinkler arms attach to.

The T-fitting has a plastic worm gear at the end which engages the plastic gear on the main shaft of the transmission to turn the wheels. What is an appropriate grease to use on a plastic worm gear to reduce that friction and hopefully increase the speed?

 

[Wamsutta]

Dow Corning 111 is what all the water softener guys use for the plastic valves. I use it on O-rings and plastic threads too. Good stuff.

 

[larry_g]

Dow Corning 111 is what all the water softener guys use for the plastic valves. I use it on O-rings and plastic threads too. Good stuff.

I concur and would add Syl-Glide as a possible candidate.

If you can disassemble the unit I'd bet you find the plastic dirty and the housing a bit rough. I find that on my sprinklers that just a clean and polish get things to work much better.

lg
no neat sig line

 

[Motown]

Krytox, is great for plastic. It won't degrade the plastic like petroleum based ludes will. But very expensive.

 

[4x4gearhead]

I concur and would add Syl-Glide as a possible candidate.

If you can disassemble the unit I'd bet you find the plastic dirty and the housing a bit rough. I find that on my sprinklers that just a clean and polish get things to work much better.

lg
no neat sig line

This. I use syl-glide almost every day on rubber and plastic seals in hydraulic systems. Ive also used it on lots of other plastic parts. Works great.

 

[Lelandwelds]

Krytox, is great for plastic. It won't degrade the plastic like petroleum based ludes will. But very expensive.

Yes, using cryogenic oxygen pump lube for a plastic lawn sprinkler is a bit expensive.

 

[JABgj]

Try a local pool supply for waterproof grease. Good for o rings and fittings.

 

[brianpgriset]

Super Lube

 

[joe_padavano]

This. I use syl-glide almost every day on rubber and plastic seals in hydraulic systems. Ive also used it on lots of other plastic parts. Works great.

Another vote for Syl-Glide. Any silicone grease will be fine on plastic and rubber parts. Do NOT use petroleum-based grease.

 

[ChevyEFI]

As a pool owner, I would probably try magic lube (II?)

They went from a nice thick version to a very thin version to make buyers feel they were getting their money's worth. I only get the thick.

 

[M6erfan]

Another vote for Syl-Glide. Any silicone grease will be fine on plastic and rubber parts. Do NOT use petroleum-based grease.

+1, some good suggestions so far

 

[vavet]

Thanks for the tips everyone.

I tried some FluidFilm - it seemed to help, but I ended up with the same problem - the arms stop turning. We're on a well, so the pressure fluctuates somewhat as the pressure tank is drawn down, the pump turns on, pressure rises, pump turns off, etc.

I changed the pressure tank/pump settings from 40/60 PSI to 50/70 PSI. That helped, but not completely.
Then I removed the inline timer/valve from the system. That helped A LOT! The inlet screen to that was also coated with sand/dirt. That probably didn't help matters, but I think the timer/valve itself reduces the pressure. I won't know for sure until I connect a pressure gauge on the other end of it to see, but I ran the sprinkler for a couple hours last night without the timer and it worked...for a while. When I disconnected the hose, the inlet screen was coated with dirt/sand again.

I'm inclined to try to run it without the timer and without an inlet screen. I don't think there there are any orifices small enough in the sprinkler itself that would get plugged.

It's a really great idea, but there's always some problem with it. I can't leave it alone to run by itself. I have to continually check on it. Last night, the joint between the two hoses started leaking, which I guess reduced the pressure enough that the arms stopped turning again. The inlet screen was not plugged that time.

 

[rlitman]

Yes, using cryogenic oxygen pump lube for a plastic lawn sprinkler is a bit expensive.

If you're filling a 14oz cartridge grease gun, then yeah, it gets crazy expensive.

But this sort of thing is used all the time in all sorts of places you wouldn't expect. From bicycle pedals, to Volkswagon sunroof seals, to Formula 1 CV joints.

And if you want to avoid paying for the Krytox brand name, you can get the same thing like this:
http://www.finishlineusa.com/products/bicycle-greases/extreme-fluoro-grease

MSRP is $15.