IDA Sailor Rudder Repair

[MHardy]

The IDA Sailor rudder on my '83 CP 16 is cracked along the rear edge. Rudder Craft says they can repair it using their extrusion welder. Has anyone had this done? I'm debating a repair or replacement. My concern is that it may crack in other places after the repair is done.

Thanks in advance for any thoughts on this.

[Tim Gardner]

Plastic welding done properly, is as strong as the material itself.  The weld material must match the welded material, in this case HDPE High Density PolyEthylene.

Any thoughts on how the original crack started & propagated?

TG

[MHardy]

Thanks for the reply. I have no idea how the crack started. The rudder was on the boat when I purchased it a few years ago. As a novice sailor/boat owner, the crack might have been there when I bought it. I'm just not sure.
I do know that it is not due to any "accident" since I've owned the boat.

[Norm]

I also have an Ida Rudder for my CP-23 that is seperated all the way down the trailing edge.  Ida Sailor told me they may or may not be able to repair it, depending on the condition of the plastic.  I will try a local place here in Annapolis.

[Tim Gardner]

There is a significant difference in the coefficient of expansion between HDPE and any metal substrate.  The crack may have occurred due to extreme temperature changes, or just quick changes.  Did you fellas notice  or experience anything like that?

TG

[skip1930]

No cracks in mine yet. What? Five six years??

I was wondering if a guy could drill a small hole clean through the rudder HDPE and 'bolt' the crack closed with a goodly amount of Marine-Tex stuff squeezed into the crack and then when squeezed out with bolt pressure, scrape off the excess Marine-Tex and after it's cured, grind/file away the head and nut of the fastener?
This assumes that the crack is up and down.

Performance wise this repair won't make any difference. It's still the same shape, and 'flows' water the same, and is still a bit balanced when fully down, [This is why I sheer bolted my rudder down to prevent a kick-up].

The only thing that must be adhered to is the the aluminium stock that goes down into the machined out hole for this stock remains tight enough with the factory fasteners that the darn blade doesn't fall off the shank.
skip.

[Tim Gardner]

Marine-Tex does'nt adhere to HDPE.  In Fact there is no surface tension "glue" that will.  It's because there are no free electrons to share with other substances.

[skip1930]

The Marine-Tex was not to 'glue' the crack together, but rather used to stabilize the crack without either edge of the crack 'working'.

The bolt with ends ground smooth is used to pull the crack together, pulling the rudder back to it's original shape, and with cured Marine-Tex as a hard filler will hold the HDPE rock steady where the split is.

That's the idea. skip.

[itsmark]

HDPE is subject to UV degradation.  Just look at a milk bottle that's been sitting in the sun for a few months.  Manufacturers stabilize the HDPE with additives when something is molded, but it rarely is effective for more than 5 years.  My guess is that your rudder sat in the sun for a long time.  Neither the HDPE or the aluminum core will degrade if the bond is not water-tight.  So I suppose the Marine Tex fix would be OK. A few stainless steel flat-head bolts, threaded to the aluminum core, and set flush with the HDPE surface, would stabilize the crack.

[Glenn Basore]

Skip,

Milk bottle?

I forgot what they look like!

Glenn B.

[skip1930]

Plastic Milk bottle? Wait Glenn, that was itsmark who brought up milk bottles.
An Almond milk paper container for skippy, maybe.

But a Mug Diet Rootbeer would be much more familiar.

LOL skip.

[Tim Gardner]

I'm sure the IDA rudders are made from virgin HDPE because they're white.  Recycled HDPE is usually some other color like black. IDA says they put an UV inhibitor in the mix. Black or dark forest green is very UV resistant, and would not need the additive.  Because my 19 sleeps in a slip, I leave the rudder down to keep it out of the direct sunlight.  A little Scunge (technical term for the crap that grows on it) develops, but is whisked away after a couple of upwind tacks. 

Maybe earlier rudders didn't have the UV protection, but a full scale crack developing?  If that's the case, the whole foil may be ready to fall off.  If that's the case, maybe it's time to drill it full of holes and wrap it in fiberglass.

TG

[bob lamb]

So what's the solution?  Is there such a thing made to glue the crack together?  I also am trying to repair a crack in my little 2.2 Mercury kicker gas tank.  I tried 3m5200/Gorilla Super Glue/ JB Weld...nothing held to this polyethylene tank.  Anyone have a solution short of buying a new tank?


Thanks for reading
BobL 

[skip1930]

Bob Lamb says-->" JB Weld...nothing held to this polyethylene tank. "

I'd try J.B. Weld in a stick [$6]. Cut the amount that would be more than necessary.
This is how I fixed and air leak on my Mercury where the fuel line plugs into the fuel inlet of the engine. I J.B. Welded that plastic collar that was cracked and interrupting the fuel flow with an air flow.

A 10 minute window is had with J.B. Weld till it can not be reworked anymore. So I stuffed this stuff around the outside of collar and then wet fingered smoothed it a bit and slipped and locked on the fuel line being careful not to foul the clip-on up by over using the J.B. Weld. And came back the next day. All was well, the fuel line clamped on and off just fine and no air leak in the fuel line. So no more 'engine shutting down' nonsense.

But first, toss the tank into the wife's dishwasher and run it for a full 'pot scrubbing cycle'. Don't dry it in the heated cycle. Have to get the oil off.

Now with a Dremel tool and cone-shaped grinding stone, chase the crack into a VEE shape, but do not cut through the crack into the tank anymore then just the surface of the polyethylene tank. Wipe the ground-a-way area with aceatone or any fast evaporating solvent.
Your just prepping and cleaning for the J.B.Weld to fill the crack.

Take the J.B. Weld and knead it 'tween the fingers until it's all one black color and force it into the crack. After it's in you can make it look pretty with a wet finger smoothie.

Or go buy a new tank. skip.

[Glenn Basore]

My apologies Skip!


Glenn