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Catalina/Capri 25/250 Sailor's Forums

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Epoxy

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danandlu
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USA
175 Posts

Initially Posted - 04/30/2007 : 10:04:51

I'm going to replace the lower rudder gudgeon with the upgraded one from Catalina Direct which will involve drilling the existing holes oversize, filling with epoxy, then drilling to the desired diameter. Are there any differences in epoxy? It's all basically the same stuff, right? Are the double syringe mixer types at Home Depot suitable?

Dan Henderson
1982 FK/TR #3328
"Chesapeake"
Missoula, Flathead Lake, Montana

Edited by - on

ct95949
Captain

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Aruba
300 Posts

Response Posted - 04/30/2007 : 10:28:17

When I first started working with epoxy on my boat I used those small quantities but I found it so useful and easy to work with that I went to the gallon and quart size with pumps from West System. You can mix a tablespoon or a half gallon, whatever you need. Get some thickening agents and some fabric and you'll be set. I'm guessing the top brands are all about equal.
When I replaced my gudgeons I installed epoxy coated plywood backing plates because the transom seemed kind of thin and weak.

Edited by - ct95949 on 04/30/2007 10:35:16

Leon Sisson
Master Marine Consultant

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USA
1893 Posts

Response Posted - 04/30/2007 : 10:31:23

No, epoxies are definitely not all alike. Personally, I haven't gotten the results I'd hoped for from the twin-syringe epoxy kits.

My personal preference is WEST products. Others have been pleased with the performance of epoxies from System 3, Raka, and similar high volume marine epoxy manufacturers. WEST in particular has a very informative website, [www.westepoxy.com], which you might benefit from studying, even if you decide to buy some other brand.

-- Leon S.

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John Mason
Admiral

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USA
687 Posts

Response Posted - 04/30/2007 : 12:12:42

If what you're replacing is the original, you'll most likely find a threaded bronze plate imbedded in the fiberglass toward the cabin side of the transom. A stout plywood backing plate is a good idea. I had to grind the bronze plate out to make the inside surface flat enough for the plywood.

I wouldn't use the hobbyist type epoxy glue for any marine application, it's just not the same stuff.

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KenDavis
1st Mate

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USA
69 Posts

Response Posted - 04/30/2007 : 12:41:58

west marine sells a kit of West Epoxy repair packets with small foil envelopes of part A and B. handy if you don't need to mix much.

I also recommend a thickener, that stuff is runny!

also wipe the area down with acetone, or laquer thinner before you apply the epoxy.

good luck,
Ken

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 04/30/2007 : 13:52:02

In my '85, part of the transom was "cored" with foam to fill the void between it and the liner, not wood, and I'm pretty sure the bronze backing plates were against solid glass. So, in my case, I doubt that overdrilling would have been appropriate. However, if you want to add strength, I might suggest you overdrill the holes in the bronze just enough to unthread them, soak a thin piece of plywood in unthickened epoxy, tape it to the inside over the bronze, plug the holes outside, pour/spoon slightly-thickened epoxy between the wood and the transom, re-drill through the wood and epoxy, use a Q-tip to swab the insides of the holes in the wood with unthickened epoxy, and then bed and bolt the gudgeon through the whole mess. Use slow-cure hardener so you don't generate too much heat.

(That's an attempt at an adaptation from Leon's book

)

Edited by - Dave Bristle on 04/30/2007 14:01:05

Turk
Admiral

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736 Posts

Response Posted - 04/30/2007 : 18:41:16

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by danandlu
 Are there any differences in epoxy? It's all basically the same stuff, right? Are the double syringe mixer types at Home Depot suitable?
<hr height="1" noshade id="quote"></blockquote id="quote">

I used department store epoxies for years until I bought some West epoxy. The store epoxies just don't get as hard as the high end epoxies like West. They seem almost rubbery compared to the glassy feel and hardness of West systems. I bought a quart, figured it would last me years. Bought another quart in 3 months!

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danandlu
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175 Posts

Response Posted - 04/30/2007 : 19:11:45

Great advice everyone, thank you all. West it is.

I wonder if instead of plywood a piece of aluminum angle would be suitable for strengthening.

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Leon Sisson
Master Marine Consultant

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1893 Posts

Response Posted - 04/30/2007 : 22:03:22

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by danandlu
 ...I wonder if instead of plywood a piece of aluminum angle would be suitable for strengthening.<hr height="1" noshade id="quote"></blockquote id="quote">It doesn't have to be plywood at all. I used about 3/16" thick epoxy fiberglass plate I made up myself. A rectangle cut out of an old boat hull would be fine too. I bedded the plate with epoxy mush to get good even load transfer from the nuts and washers to the hull.

-- Leon S.

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Dave Bristle
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Djibouti
10005 Posts

Response Posted - 04/30/2007 : 22:18:33

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by Leon Sisson
 <blockquote id="quote">quote:<hr height="1" noshade id="quote">Originally posted by danandlu
 ...I wonder if instead of plywood a piece of aluminum angle would be suitable for strengthening.<hr height="1" noshade id="quote"></blockquote id="quote">...I used about 3/16" thick epoxy fiberglass plate I made up myself...<hr height="1" noshade id="quote"></blockquote id="quote">
Even better! The objective is a flat, squared-up surface for washers to tighten against, and solid material (thickened epoxy) filling the gap between that and the transom, so the load isn't supported just by the edges of the backing plate. If you go with aluminum I wouldn't use an angle extrusion--i think that's unnecessarily stiff. A sheet would be better. I'd still use the epoxy behind it to even out the load. I made some stainless sheet backers for a similar application.

Edited by - Dave Bristle on 04/30/2007 22:20:59

danandlu
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USA
175 Posts

Response Posted - 05/01/2007 : 09:07:45

As long as I'm asking questions: Is it a good idea to coat the new bolts with 4200 before insertion? I don't want any leaks.

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atgep
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1009 Posts

Response Posted - 05/01/2007 : 09:47:27

One more note on epoxy. It will "blush" after the coat dries. The blush needs to be removed before you add another layer of epoxy or your bond will be weak.

Tom.

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Dave Bristle
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Djibouti
10005 Posts

Response Posted - 05/01/2007 : 10:18:43

Coating the bolts won't keep water out--you need to create a tight seal outside of the boat. My recommended steps for bedding a piece of hardware are:
1. Use an over-sized bit to bevel the edges of the holes in the fiberglass to accommodate some extra sealant around the bolts. If using a power drill, run it in reverse to keep from digging too deep.
2. Put polysulfide (not polyurethane) caulk on the base of the fixture (gudgeon) with the bolts in place--especially around the bolts.
3. Insert the bolts into the hull and hand-tighten (barely) so that a small amount of the caulk is squeezed out around the edges.
4. Let the caulk cure completely--generally at least 2 days.
5. Wrench-tighten the nuts from inside while holding the bolts stationary outside--a two-person job in this case. This puts pressure on the "gasket" you've formed and doesn't break the seal of the caulk on the screw.
6. Use your fingers and/or a blade to zip away the excess caulk around the fitting.

The good news is your gudgeons are both above the waterline. Best of luck!

Edited by - Dave Bristle on 05/01/2007 10:26:23

danandlu
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USA
175 Posts

Response Posted - 05/02/2007 : 10:01:25

Tom & Dave,

Thanks for the tips.

It's not that I'm hung up on 4200, it's just that there's no supplier for marine items near me (200/500 miles) and I'd like to get this done this weekend. Will 4200 serve as a replacement for polysulfide caulk?

Edited by - on

John Mason
Admiral

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USA
687 Posts

Response Posted - 05/02/2007 : 12:51:57

4200 is polysulfide.

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Dave Bristle
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Djibouti
10005 Posts

Response Posted - 05/02/2007 : 18:07:13

Actually, its polyurethane, but less aggressively adhesive than 5200.

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danandlu
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175 Posts

Response Posted - 05/02/2007 : 18:29:37

I went to the only supplier here, a powerboat dealer (notice I didn't say the "stk-pt" word

), who has a small inventory of marine items - some that cross over to sailboats, found the West epoxy (yes!) then I asked if any polysulfide caulk, he said no (darn).

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Put polysulfide (not polyurethane) caulk on the base of the fixture <hr height="1" noshade id="quote"></blockquote id="quote">

<blockquote id="quote">quote:<hr height="1" noshade id="quote">4200 is polysulfide.<hr height="1" noshade id="quote"></blockquote id="quote">

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Actually, its polyurethane<hr height="1" noshade id="quote"></blockquote id="quote">

So.... I don't mean to beat this to death.... but....

Edit:

<blockquote id="quote">quote:<hr height="1" noshade id="quote">Ed Schenck
Huron, OH
03/28/05 at 6:14
Hunter 27_75-84 Sealants
From a document in my WORD file:
"Sealants:
Polysulfides You can—and should—use polysulfide to bed almost everything. A synthetic rubber with excellent adhesive characteristics, polysulfide is the most versatile of marine sealants. As a bedding compound it allows for the movements associated with stress and temperature change, yet maintains the integrity of the seal by gripping tenaciously to both surfaces. It even adheres to oily teak and is unaffected by harsh teak cleaners, making it the choice for bedding teak rails and trim. It is also an excellent caulking compound since it can be sanded after it cures and it takes paint well. (The black caulking between the planks of a teak deck is invariably polysulfide.) "3M 101", "Boat Lifes’s Life-Caulk"

One caution: do not use polysulfide to bed plastic—as in deadlights, portlight frames, or deck fittings. The solvents in polysulfide will cause acrylic, polycarbonate, ABS, and PVC to harden and split. Only when you know for certain that a plastic fitting is made of epoxy, nylon, or Delrin can you safely bed it with polysulfide. Below-the-waterline through-hull fittings fall into this group, but if you have any doubt, use another sealant.

Polyurethane Consider polyurethane an adhesive rather than a sealant. Fittings bedded with polyurethane typically cannot be separated without damage, so do not use it on anything you might need to dismantle in the future. Polyurethane is an excellent sealant for hull-to-deck and hull-to-keel joints and a good choice for through-hull fittings, rubrails, and toerails. Do not, however, bed teak rails with polyurethane because teak cleaners damage it. Like polysulfide, polyurethane should not be used on acrylic, polycarbonate, PVC, or ABS-based fittings.
"3M 4200", 3M 5200"

Silicone If you think of silicone as a gasket material instead of a sealant you can probably intuit its appropriate uses. It is the best choice for bedding components that must be periodically dismantled. Its excellent insulating properties make it ideal for bedding dissimilar metals—stainless hardware on an aluminum spar, for example. And it is—by default—the only one of the marine sealant trio than can be safely used to bed plastic. However, silicone should not be used below the waterline. And because it depends upon mechanical compression to maintain its seal, silicone is also a poor choice for sealing hardware on a cored deck.

Keep this quick review in mind when you’re considering a bedding compound:

Polysulfide—a sealant suitable for bedding everything except plastic.
Polyurethane—an adhesive that forms a permanent bond.
Silicone—a gasket material and electrical insulator."

<hr height="1" noshade id="quote"></blockquote id="quote"> From sailboatowners.com (I did a Google).

I answered my own question.

Thank you all for your input. I think I can get this done!

Edited by - danandlu on 05/02/2007 21:35:36

dlucier
Master Marine Consultant

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Virgin Islands (United Kingdom)
7583 Posts

Response Posted - 05/02/2007 : 21:39:39

That's actually an article written by Don Casey.

[url="http://www.sailnet.com/forums/her-sailnet-articles/21059-choosing-using-sealants.html"]Choosing and Using Sealants[/url]

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Dave Bristle
Master Marine Consultant

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Djibouti
10005 Posts

Response Posted - 05/02/2007 : 22:00:15

One product not discussed there is LifeSeal (from the makers of LifeCaulk polysulfide). It's a mix of silicone and polyurethane--recommended for plastics and just about everything else, and from what I've seen, it's not substantially more adhesive than polysulfide. I definitely recommend it over straight silicone, which has several problems--deterioration in sun and residue that can be almost impossible to remove.

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John Mason
Admiral

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USA
687 Posts

Response Posted - 05/03/2007 : 10:53:26

Pardon my misinformation, don't know where I got the idea that 4200 is polysulfide. Must be 'cause I use LifeSeal for everything.

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mashedcat
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USA
194 Posts

Response Posted - 05/03/2007 : 12:15:38

At Strictly Sail West, I went to a seminar on fiberglass repair presented by the guy who manufactures MAS epoxy products. Learned a lot. The guys who do the seminars don't push their own products, but i would definitely check out the MAS products before spending my money. I know I will use that product exclusively from now on. No problems with blush with them. You don't have to remove it because there is none. There are many more reasons for choosing them too numerous to mention here, but at least check them out.

Edited by - mashedcat on 05/03/2007 13:11:11

Gloss
Master Marine Consultant

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USA
1916 Posts

Response Posted - 05/03/2007 : 16:41:27

A friend of mine, who lives in St Johns in the Virgin Islands says everyone down there is Using the MAS system now instead of West. When I run out of my west epozy I'll change over to MAS myself. The amine blush with West is really a pain to work with. I believe most of the more modern epoxy formulations like MAS do not have amine blush. West is an old epoxy, and I wonder if they just haven't kept up with the times, or maybe non blushing epoxy is proprietary.

Good luck

I backed up my new gudgeons with stainless fender washers. I also drilled it out so I could use 5/16" stainless machine bolts instead of the stock 1/4" bolts. Tim Allen has nothing on me.

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