Plaction wheels coming apart

[cire]

Originally Posted by martin417

We bought brand new 6" Andymark plaction wheels this year. We noticed after the scrimmage that one of the wheels was cracked. Today, one of the wheels on our practice bot completely came apart. It appears to have originated at the hub area. The entire hub disintegrated intiny pieces.

Has anyone else had problems with Plaction wheels? A possibility we thought of is the loctite. I know some plastics don't like loctite. It is likely that when the sprockets were assembled, some loctite got on the plastic. Is this a likely culprit?

http://www.useloctite.com/library/faqs3bd1.html

Q: Do you recommend using anaerobics on plastics?
A: Anaerobics are generally not used with most plastics. Anaerobics will stress crack some plastics including many thermoplastics like ABS and polycarbonate. If the product is used for metal-to-metal but in close proximity to plastic, there is the possibility of excess liquid product or vapor affecting the plastic. In the case of compatible plastics like acetals, the anaerobics are simply not the best family of products for effectively locking and/or sealing. Often cyanoacrylates are substituted if they meet the other application parameters.



Plaction wheels are made out of polycarbonate, you are most likely correct in thinking that may be the cause.

[IndySam]

Polycarbonate hates loctite. I have seen a sheet crack just from being under a little tension and having loctite driped on it and left to sit overnight

[JesseK]

We use lock nuts in all of ours, and haven't had a problem. We had little kids driving on our 6" Plaction wheels off and on for ~12 hours overall at the 2010 Science & Engineering Festival. They held up fine, though granted they weren't being banged over a bump there at the S&EF. Last year's 4" Plaction wheels were slammed from forward to reverse more times than I know, and they also engaged in a few high speed impacts too. They're still fine after 3 regular and 2 offseason competitions. We're using KOP wheels for 2012, the hubs of which look like identical plastic to the Plaction wheels. We've banged them around on the ramp a bit, but we'll see after competition season.

[PurpleRoboSnail]

we used 8in plaction wheels in the israel regional and one craked when we went over the bump. After that we switched to preformane wheels on front.
last year we used 8in plaction wheels and they didnt crack.

[RRLedford]

We recently got some new AM plaction wheels to test for improved traction on the bridge. IMO the bearing fit was seriously off in the too-tight direction.
After testing and not liking the results with the wheels, we could not get the bearings out to transfer them into alternate wheels.

-Dick Ledford

[kevin.li.rit]

Ive have had the outer rim of the wheel crack and throw off the tread. No loctite was used on the wheel. It didn't disintegrate though. It was still usable.

[martin417]

The mystery is solved. We didn't use self locking nuts because the ones we had were too tall to fit. We had a student put the wheels together and he use too much blue loctite (blue seems to be worse on polycarb than red) anyway, every wheel had cracks radiating from the nut locations.

Note to all: NEVER USE LOCTITE NEAR POLYCARB!!!!

PLACTION WHEELS ARE POLYCARB!

[matteo2171]

Our team used them last year on our drive train and this year on our shooter (with trad covered in gorilla tape to reduce tear on ball) and we never had problems with them we push bearings in by hand and use nylock nuts no locktight