I have a Hobie 18SX with EPO rudders. I have noticed damage to the rudders in the form of a puncture where the set screw used to control rake has worn (crushed) into the rudder. I want to fill the holes with somesort of epoxy to repair the rudder but I want to select a hard epoxy to minimize the time it takes for the problem to reoccour. I was actually thinking about using JB WELD but I wanted the opinion of those much smarter than me before I proceed. The holes are about 1/4 inch diameter and probably 1/8 to 1/4 inch deep. Thanks for your input.

I think I'd be inclined to epoxy something like a short S/S self tapping screw into the rudder head at that point to take the load.

Get some System Three, MAS or WEST System epoxy and some filler. I dont know what JB WELD really is, but the three epoxies I mentioned are suitable for home use and will give a good result.

If you could post some pics of the damage, you will probably get all the advice you want on how to do a repair.

My recomendations.
Drill out the hole and remove all debris and damaged material. then fill with a good quality filler and epoxy. I had a hole in the head of my tiger rudder head and filled it with West system. Hard as a rock and very stable. when using the resin let it fil the hole then lightly tap the rudder with a rubber malet to allow any trapped air to escape. Make sure to tape the work area off first as the epoxy is hard to get off once set. Fill the hole completely but allow a slight upward bubble to form on top. The resin epoxy will settle as it goes off. the bubble can then be sanded smooth and your good to go. Btw gel coat will not readily stick to most epoxy's so keep the epoxy as the finish coat. Hope this helps.

JB weld is an epoxy based adhesive with fillers for adhesion and resistance to abrasion (very likely finely powdered aluminum, talc, and lord knows what else). It should actually hold up quite well as far as abrasion resistance goes.

If you want to fill with epoxy, I would make a mixture of any good laminating epoxy (West, MAS, etc.) with aluminum powder (abrasion and UV resistance), and cabosil. The cabosil will make it very thick and almost impossible to sand...this is just the long way around to make your own JB Weld (but you can make it as thick/thin as you need).

You may get better advice specific to the H-18, but most of the H-16 sailors I know (including myself) just remove the set screw. The adjustable bar in the upper casting controls how far back the rudder go, which is what's most important. I guess the thinking is that, while underway at least, the rudder will be pushed back and there's no need to limit it's forward range.....not much room for slop there anyway. I'd recommend you get rid of the set screw after making the repair and see how it goes.....you can always put it back later.

Repair the hole with west system and fibers - it will be plenty strong. Get rid of the set screw. To stop the forward slop between the rudder blade and the casting, put some epoxy putty (the green roll stuff from home depot works fine) in the casting. Tape some saran wrap over the rudder blade and swing it down into the casting at the desired rake and let the putty set. The saran wrap stops the putty sticking to the rudder.

This is how we fix up our Tiger rudders (which use very similar castings). You could also glue in bits of neoprene for a similar effect but bedding with epoxy has worked well for us.

Chris.

Yah, I had the same problem also when I converted from the old TheMightyHobie18 Rudder Castings to the new system in 1988 (I believe). The two nylon adjustment screws act as a point load and punch holes onto the "old" EPO rudder blades exposing the core ....

As recommended above I used WEST Epoxy w/ fillers and on the last coats I used some small pieces of fiberglass cloth w/ WEST Resin .... then sanded it fair.

Now how did I prevent a re-occurance???? I'll explain a trick someone else taught me ....

First, take those nylon screws out and throw them as far from the boat as you can!!!!

Next, I did have a reasonable idea of where/how much rudder rake I needed, which is what those screw were SUPPOSE to control. So upon a suggestion from a knowledgable friend I wrapped the rudder blade in "Plastic Food Wrap" ... placed/squirted a large glob of silicon onto the bottom of the rudder casting where the nylon screw HAD been ... and then pressed the rudder blade into it's proper down position ... allow to harden over-night. You have a semi-instant flexible bumper ... If you don't like the rudder tune, remove the silicon and try again ... stretchable "Shrink Wrap" will also work ... {you may wish to repair the blades ... reinstall them ... measure the rudder rake w/ the set screws ... mark the casting for the leading edge of the blade ... remove and dispose of the nylon screws and then do the silicon trick if you do not have a "good" feel for the rudder rake setting ... just an idea}

My TheMightyHobie18 has been raced/sailed 12 of the last 20 years (it was apart for 8yrs as I sailed my P19 but that is for other reasons...) I have redone the silicon twice in 12yrs of sailing effectively. I'm thinking of redoing it in the spring as I'm thinking of coating my origonal "old" EPO rudder blades w/ WEST Epoxy and then painting them for UV protection (a nice white I think) So it seems to be a good solution for this problem to me .....

Give it a try .... it's not permenate ... requires no holes ... is easy to do ....

Good Luck
Sail Flat, Sail Fast, Sail SAFE
Harry Murphey
H18Mag/#9458, Fleet54/Div11
P19MX/#86, CRAC-Open Class

PS/FYI: I have done alot of WEST Epoxy work/repairs and then Gellcoated .... You need to expose the curing Epoxy to a good 3-4 day min of bright sunlight so the UV's can complete the curing of the epoxy through the "Amine Blush" phase has been my experience ... (I have two bow repairs that I have been exposing for several years now .... I quess it's time to get some gelcoat w/ wax and properly finish the repair ... HA HA HA ... but true.)

PS2: Cut the "plastic wrap" along the trailing edge of the rudder blade ... gently pull the blade out of the down position .... then remove the "plastic wrap" layer by layer ... you may need to leave the last layer in place and just trim off the excess material ...

Excellent advise from all as usual. With the aftermarket sails I need to find that sweet spot before I make it a perm repair. It seems like it felt good after I tuned the rudders to the Hobie 18 performance manual. I think I will fix the hole and retune to that manual and then sail a couple days to confirm I like it and then follow the above recomendations. Thanks again guys.

Thisd sounds correct- but--- Epoxy doesn't cure with UV, just faster with heat, assuming close to the proper ratio between amine and epoxy has been mixed. You are supposed to wash off the amine blush then sand it. The dogma is to then use epoxy with fumed silica gel= gelcoat. (PS: It yellows)

Polyester does cure with UV- or ozone + air inside the unused can, eventually. But it doesn't do well on top of epoxy.

with the epoxys mentioned you will want to weigh the part a and b on a gram scale before adding any fillers. The epoxy sold in the 2 part siringe or hobby shops 15 or 30 min stuff can be mixed eyeball measure just dont try to make it set faster by adding more hardener. Chopped glass or milled. Carbon fibers are a good thickener in a pinch some of those other fillers like cabosil you have to buy a lot more that you need. Another good thickening is microballons they are either white or rust colored sold in hobby stores also. Should be able to gelcoat over epoxy if its sanded and cleaned with alcohol.