No matter how tight I tighten my mast ball it has always been backed off (loosened) a turn or so when I check it after a de-rig. I thought some type of thread locker/sealant might do the trick. I decided to go with an old standby sealant/adhesive I have used on many things successfully for years, "Goop."
http://www.homedepot.com/p/Amazing-Goop-3-7-fl-oz-All-Purpose-Adhesive-140211/202533796
After removing and cleaning the threads on the ball and rod I applied a bead to both and reassembled tightening the ball very tight. I then put aligning marks on the ball with a silver Sharpie and the rod with a black Sharpie. Several days later I went out for about 3 hours and upon making shore inspection showed that the ball had backed off about a quarter of a turn.
Any suggestions to keep the ball from loosening?
Grease the ball/mast base surfaces.
I've never used goop. Is it actually a thread locker? I would stick with loctite. There are loctite formulations specifically for use with plastics.
As a last option, you could drill a hole through the ball and striker rod (horizontally) and then tap in a roll pin which would mechanically stop the ball from unthreading
sm
Edited by Dogboy on Jul 30, 2016 - 02:25 PM.
Steve M.
I use dish soap, namely Dawn, or food grade silicon (spray) for the ball/base lubricant. Much less messy than grease.
Dogboy wrote: I've never used goop. Is it actually a thread locker?
Here is the manufacturer's description.
Product Overview
Amazing Goop is one of the strongest, most flexible all purpose adhesives ever created. It's designed to adhere to virtually any surface so you can fix what other glues simply can't.
California residents: see Proposition 65 information
Strongest single component adhesive available
Waterproof - bond remains secure even when exposed to water
Temperature resistant - remains flexible, even in extreme conditions
Won't crack or break like super glues
Washer and dryer safe
Note: product may vary by store
Do you have the right ball? That looks like an older mast base. I think the 1 1/4 balls are threaded differently than the newer 1.5" balls. New England catamarans has the older balls.
Dave Bonin
1981 Nacra 5.2
I have 2 Nacras with the same mast base/ball that you use.
Your problem is very easy to solve.
Screw the ball hand tight, spray with jigaloo, or similar... go sailing, & forget about it. yes forget about it.
The mast base is not polished, & it will "grip" the ball.
As the mast rotates, it will rotate the ball, BUT, it does not rotate the ball, let it stay there while it pivots on top, & then rotate it again, unscrewing it.
The ball simply turns a bit as the mast rotates, then turns the other way as the mast turns back. At the end of the year, the ball will be within a 1/4-1/2 turn of max tight, & everything is fine.
It won't unscrew itself, so go sailing & ignore it.
the ball is delrin, almost nothing sticks to it, you cannot "glue", or loctite it to the SS rod. This one has been "turning" for 5 years.
Edited by Edchris177 on Jul 30, 2016 - 10:54 PM.
E C Hilliard
Nacra 5.7
Bombardier Invitation
Wolfman wrote: Do you have the right ball?
Here is the ball I have on the boat now except black not white.
Edchris177 wrote: It won't unscrew itself, so go sailing & ignore it.
Thanks Ed. That is my conclusion as well.
Murray's says the ball is nylon, but nylon or delrin more or less the same issue with bonding to anything.
It's pretty hard to mix up the old style (1 1/4") ball & the newer system. The old DS rods were thinner, 7 as Dave said, they won't thread onto the newer DS rod.
E C Hilliard
Nacra 5.7
Bombardier Invitation
i have always been amazed that nacra didn't 'polish' the mast base inside where it sits on the ball. they are so rough that they always ground off the top of the ball in one season. if i was a machinist, i'd polish the depression in the base to slightly larger than the ball diameter.
a couple of years ago, i started cutting a round disk out of a plastic milk container and inserting it into the base so the ball was rubbing on plastic and not the cast metal. a touch of grease and it rotates like a charm. i have to replace the disk each year, but it's way cheaper than buying a new ball.
i wouldn't worry about the ball unscrewing itself. that would probably never happen.
j
ah, the dreaded 'double-post'......
j
Edited by arch on Aug 01, 2016 - 01:56 AM.
i have always been amazed that nacra didn't 'polish' the mast base inside where it sits on the ball.
Here is what my mast base looks like now after 1) 2 wash coats. 2) three coats of Awlgrip 545 primer and 3) 3 coats of Awlgrip 2000 two part urethane.
It isn't polished, and who knows how long it will last, but it does look pretty good now.
Edited by dmgbear55 on Aug 01, 2016 - 10:35 PM.
arch wrote: i have always been amazed that nacra didn't 'polish' the mast base inside where it sits on the ball. they are so rough that they always ground off the top of the ball in one season.
I too have noticed how rough the mast base is on the bearing surface and intend to do some smoothing/polishing during the off season, but for now, on the water as much as possible!
arch wrote: a couple of years ago, i started cutting a round disk out of a plastic milk container and inserting it into the base so the ball was rubbing on plastic and not the cast metal.
I also like the mast chip concept as that's the way Hobie deals with this problem on the Hobie 16 and it works quite well.
I have never bothered with anything, other than a spray of jigaloo.(And I don't think it does very much). I notice on both Nacra that as I manually turn the mast, the ball turns with it. It doesn't seem to wear out the threads, & I have had the same ball on both the 5.7 & 5,0 for five years now.
If the ball doesn't turn, it would certainly wear the top.
E C Hilliard
Nacra 5.7
Bombardier Invitation
Wax the mast ball, put a big blob of MarineTex in the mast base, and insert the ball. Leave overnight.
You now have a smooth bearing surface and will never have to replace the ball again.
We used to have to replace the ball after a long distance race (Tybee, Texas, etc). Not any more.
Thanks Mike. Sounds like a great idea. I'll give it a try the next time my mast is down.
Gorilla glue will expand with moisture and help lock the ball tight to the threads. Just make sure both surfaces are wet before applying.
i use it to lock a stainless rod to plastic Turcite nut. Gorilla glue has worked the best of all others I've tried.