Is there anything better than

Superglue?

[smells so good]

I have one of these traveling lawn sprinklers [lrnelson.com], and I love it! By far the biggest complaint is with the gearbox, and that's the problem I'm having. But I'm a fix-it kinda guy and I want to fix this thing, not go buy a replacement that's almost guaranteed to break.

The sprinkler arms fit into a Tee. That Tee then screws into a sleeve which drops into the gearbox. The worm gear is the bottom part of this sleeve, so as the arms turn (thrust), the worm gear turns, and the wheels turn. Another brass sleeve fits inside the (nylon?) sleeve and fastens the arms to the gearbox.

It's very easy to want to pick this sprinkler up by the Tee that holds the arms. DON'T DO IT! The sleeve broke, right at the top of the worm gear. I suspect that most of the reports about stripped gears on this unit can be traced back to a broken worm gear. Now the arms turn, but I'm watering the same spot all day long. The rest of my yard hates me for that and insists on pushing up dandelions.

As far as I can tell this sleeve and gear is made from some sort of nylon? I have tried a 2-part epoxy. It failed to hold. I have tried Red Hot Blue Glue (for PVC/ABS tubing). It failed to hold. I have tried Superglue. It holds, but only for a short while (days to weeks). What in the world can I use to weld this stuff back together. I promise, once it's repaired I will never pick the unit up by the arms again.

[Frequent]

Try some JB Weld... but really just buy another sprinkler and don't break it this time.

Freq---

[smells so good]

I thought about JB Weld after I posted the message. That usually works for just about everything. I'll pick some up on my next outing.

buy another sprinkler

It was an expensive proposition the first time.

don't break it this time

I swear, it's designed to break. I didn't do it on purpose.

Is anyone familiar enough with manufacturing in general to know what this sleeve/gear might be made from? It looks like PCV, or plastic. Is nylon the material they most likely used? The manufacturer seems to be ignoring pleas to manufacture metal gears. I wonder why...?

[BeeDeeDubbleU]

Learn to rain dance ... much cheaper ;)

[percentages]

>Is nylon the material they most likely used?

From your description it is most likely a nylon based product, which is notoriously hard to repair with any type of adhesive.

I have had the same problem with car parts. Whenever possible I have machined a metal (aluminum/brass) replacement part....100% solution forever! (GM have a gearbox part made of nylon....guaranteed to fail within 7 years!) The bushels on many car manufacturer's steering columns are also nylon, they don't fail......but "squeak" like crazy!

When machining a replacement part for a nylon part isn't possible/practical the only real success I have had is with my soldering iron!

Now, fair warning folks......the fumes are toxic, the process is nasty, and I'm not suggesting you do as I do. But, melting the nylon with a soldering iron produces the only (welded) joint I would ever trust afterwards. It requires a steady hand and patience......but works the best!

Only try it under a strong blowing A/C duct, or outside with a fan in place. Choose a bit suitable for the joint size.....and practice first, you don't get to make many mistakes before the part becomes totally unusable/destroyed!

[texasville]

Liquid nails.

[Automan Empire]

It is best to exactly confirm the type of plastic. If it is indeed nylon, melting-together will work best, although the joint is brittle. I use this method on a variety of plastic items, with good ventilation. I have even seen a "plastic welding kit" that looks like a soldering iron that blows hot air on the work, and comes with plastic "welding rods."

For gluing plastic in general, try plastic model cement. The non-toxic kind is worthless; get the toxic stuff. ;)

Black plastic is probably ABS. Much other plastic is probably PVC. Don't go heating these if you don't want to be breathing toxic #$%$ like phthalates etc. ABS or PVC cement and (important) primer can be bought in the plumbing department.

Clear polycarbonate is hard to fix and DONT heat it because it is made from bisphenol A. I would try model cement on it. I believe PC is "solvent-welded" (chemically melted together) but I don't know how, probably xylene or something.

JB weld works best on plastic when you can well-encapsulate the break area; flexing tends to break the bond.

Of course, replacing the part, even fabricating a new one, is always best, as repaired plastic is inevitably more brittle than it was before breaking in the first place.

Have fun and I share your plastic pain,
-Automan

[lawman]

Or you could spend some extra cash on one of these [rittenhouse.ca]. :)

[smells so good]

Thanks Lawman. I got two references for that one. The cost is about the same for either unit, depending on where you might shop. It looks like I got the wrong one!

Meanwhile, I picked up some JB Weld this weekend. My superglue is still holding, but JB Weld gets the next attempt. I can build the joint up on the outside of the sleeve, but not on the inside. I'm thinking about the soldering iron method, but my past history with things like that isn't so hot (pun intended). Liquid Nails could be interesting.

It's a good thing for one of my neighbors that I'm an honest man, I spotted their traveler this weekend, and I know how to pull that gear out in about 30 seconds. I was looking at it, then I thought, it's probably broken too. Besides that, it's not worth explaining to a judge.

[bird]

Formic acid is a good solvent for most polyamids. You might try to use this for "solvent welding". If the two parts fit exactly together, then a few drops on the crack will probably pull in on their own. If you add the right amount, it may solve enough of the two surfaces to create a sufficiently stable new connection. Of course, once you have removed the residues of all the different types of glue you already tried, the fit might not be accurate enough anymore...

Only use formic acid under very good ventilation.