Pylon Repair

jajaja! have some apple juice!
cheers!

Bill:

I have gone out sailing a couple of times and the boat sure feels much stiffer than it was before, also if i lift up one of the hulls while the boat is sitting on the ground, the other hull gets off the ground right away (1-2 inch gap), while before the repair you could lift the first hull a good 6-7 inches before the other one took off.

I still need to go out a few more times, also with stronger winds to make sure that everything stays in place.

If you decide the welding option keep in mind hobie Nick´s advice about the thinness of the alu on the pylons, When i did the job I put an alu sleeve (made from a broken HC16 front beam) on the inside of the pylon to act as a backup for the welding, otherwise the heat will melt the alu and the holes will get bigger.

Good luck

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1983 HC16

yesterday I thought of an idea to strenghten the pylons and make that pylon to casting connetion as strong as posibble using the 1/2" bolt.
Pour Seacast into the pylons to make it a solid core. Tape over the two holes with alum tape and fill to the top flush. Then re drill the pylon for 1/2" bolt. Seacast is used to replace transoms and stringers. It flows like resin with fiber in the mix but will cure as strong as a block of solid fiberglass. The bolt will pass thru a solid core of super strenght fiber.
It will add weight to the hulls, but hey if the pylons are that worn then ure boat is old (like mine) and a little weight wouldnt be a problem. Considering the peace of mind and no racing in nationals.
Mine are elongated and have lost chunks of alum to salt corrosion.

Anyone?

Instead of filling the entire pylon, insert a foam plug two or three inches below the bolt hole. That way you still get the strength but won't add unneeded weight.

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If u look down inside the pylon theres a rivet sticking in. Apparently this has some angle tab or something on the inside of hull used to set the deck at the correct height.
I would think its best to lock the seacast in the pylon by adding some rivets a few inches below the bolt hole around the pylon (3 or 4) to add some grip before pouring the resin/fiber in. Just in case the seacast doesnt grip the slick alum pylon walls.

If we are pluging the pylon with foam to reduce weight we would have to foam to the desired level before the rivets are popped in.

And add a vent tube or drill down the resin once set to clear the airway.

Filling the pylons sounds like a good idea. My pylons are filled with a foam plug but the top 2 to 3 inches can be remover.
I just picked up a piece of a broken mast and I will experiment with reinforcements to be welded to the inside of the pylons. I think the plates could be riveted to the pylon just below the casting at the bottom and welded at the top. The originals holes could then be welded closed and predrilled. The tops of my pylons were rolled over from the wear, and. with the extra weld they might have more strength.

Bill

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Brig Bill

People, Secast is not that expensive but shipping of hazardous stuff to Puerto Rico is. I had this experience with Duratec I had shipped from California to PR.
Im looking for other options as to pouring fiberglass resin mixed with chopped mat into the pylons. This is was Seacast is basicaly. These I can get localy.

My question is: How can I get the resin to harden slower and not cook or crack inside the pylon as it sets and still get a full cure?

I will be filling the pylon for about 4 inches down up to the top and this may produce too much heat...

thanks!

Two methods:

1) Use less catlyst (polyester resin). Halve the amount recommended. It will still go off, but slower.

2) Lower the temperature (might be a bit tough in PR). If you've got access to the inside of the hull, pack ice around the pylon.

Even though I have worked with fiberglass a lot, I havent poured a block of resin and chopped mat. I am woried that it will crack of simply be too brittle.

Resin and mat mix to a pan cake mix consitency and poured about 4 inches deep into the pylon. I will plug the pylon with foam at deck level so I dont pour all the way down into the pylon and add unneeded weight. Then redrill for the 1/2" bolts to attach casting.

Will this method give the results Im looking for in my pylons?

Has anyone poured a block of resin with chopped mat before?

thanks!

You can also get a slow catalyst to increase the cure time. I know West Systems has one and so does MAS. MAS has one for warmer climates.

To reduce the size of the resin block, do as you said on the bottom and don't fill much above the bolt hole. Maybe and inch or so. This will reduce the amount of heat the curing resin produces.

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Nick

Current Boat
In the market
Previous boats owned
'74 Pearson 30
'84 H16
'82 H18 Magnum
St. Louis, MO

Note that's for epoxy resin, not polyester.

I could go with the west system which I used before but damn a gallon with hardener and pumps is quite expensive!!!

I guess Ill have to do some tests with polyester resin first inside a paper cup to guage the heat and strengh after curing.
Or wait a few weeks and order the Seacast, paying far more for shipping than product.

An elegant alternative to the "brute force" solution of filling the pylon with pounds of resin would be to laminate a few layers of Kevlar cloth to the inside of the pylon with epoxy resin.

Kevlar is much more abrasion resistant than carbon fiber, almost as light and is much stronger than fiberglass.

The difficulty is in getting a good bond between the aluminum and the epoxy. The aluminum has to be abrasively cleaned and then etched (West System #860) to get good adhesion.

Resin, hardner, etching kit, Kevlar tape for about $100 at Jamestown Distributors.

Then again, you could use the core from a roll of paper towels, insert it into the pylon before you do the "pour" of resin and it would probably take care of the heat problem and reduce the weight (leaves a hole in the middle where the resin is just dead weight).

Matt also brings up a good point. Check at Jamestown Distributors for pricing on any boat building/repair stuff. I know shipping is a major expense, but their prices are usually the best around.

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Nick

Current Boat
In the market
Previous boats owned
'74 Pearson 30
'84 H16
'82 H18 Magnum
St. Louis, MO

Well here is my fix for the worn pylons. I got a pylon from a scrapped boat and cut the rear part off. I fitted about 4in lengths inside the pylons on my boat. You can see in the photos how badly the pylons were worn and cracked and the holes elongated. A friend and fellow Hobie Cat Sailor welded the holes, around the top, and down the back of the inside. We then ground off excess and put the tramp on. I still had the pylons being worn problem. I refused to double beer cans, so I purchased some sheet aluminum at Home Depot, in different thickness and made shims. With the pylons fitting tight I redrilled the bolt holes. The boat is tight and sails great. I hope the fix helps someone else. My friend and Hobie sailor is an excellent welder and metal sculptor. The pylons were wrapped with a wet cloth while being welded with a TIG welder and overheating the fiberglass was not a problem. I have posted the pictures of the repair.

Hope this helps
Bill

Here is the link to the photos


http://www.flickr.com/photos/brig_bill

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Brig Bill