And so it begins

[jibes138]

Epoxy question for 25

While I appreciate the elegance of your solution I have a few questions and comments. The method you are using requires using secondary bonds for attachment of fully cured FRP to the hull? Followed I assume by also secondary bonding internal plys to the hull and previously bonded plug?

Wouldn't it be advantageous from a bonding strength perspective to apply the layup to both the inside and outside so you gain the benefit of primary bonding to each other while secondary bonding to the hull on both sides? Seems like a stronger repair would result but it would be harder to implement? Also West recommends a 12 to one bevel and you don't suggest you are spreading the load that widely across the area?
What say you young padawan?

 

[25yearslater]

Good questions jibes. First let's remember primary bonds are the bonds formed through the chemical reaction. Secondary bonds are formed through the polymer tails wrapping around the microscopic tails of the laminate. Adhesion if you will. The larger surface of the beveled repairs spreads these tails over a considerable area resulting in a structure of exceptional strength. So what I considered was the flimsy walled transducer housing and the even weaker flange both comprised of a thermoplastic. Since this operated for years with no structural problem it seemed safe to assume a plug made of biaxial cloth and epoxy would present a much more solid filler. By bonding with epoxy the resultant repair should exceed the transducer strength. Also consider the flange of the plug is what will take the greatest stress from the water pressure. Since we are dealing with a machined hole that didn't weaken the overall structure for many years it seemed acceptable to fill with a stronger plug that essentially replaces the transducer housing. Thus is my reasoning.

 

[Panta Rei]

So what I get from you two's dissertation is that I can't just put a sock in the two thru hulls that I won't be using until I can get somewhere were I can pump my *&^% overboard.
Would you call that tertiary bonding?

 

[25yearslater]

Hey Todd. The socks might be prone to osmosis. Essentially I am not rebuilding the hole but replacing the transducer with a solid piece.

 

[25yearslater]

The internal bevel and patch episode. With the plug installed it's time to finish up the internal backup patch. Since the plug was 1/16 inch below the inside of the hull a slight bevel was ground out to 4.5 inches. This had successive layers of +/-45 biaxial cloth (3 each) at 3, 3.5 and 4 inches applied with epoxy. The final 4.5 inch patch was 0/90 biaxial. No particular reason other than it matched the roving so that when it is painted it isn't as noticable. So with that the hull remains smooth internally without a bump and is very strong. Next up the outside fairing.

 

[maine89]

Watching intently

 

[25yearslater]

Well there it is. Sand and coat with 6 coats of epoxy and paint. The plug was overfilled with epoxy and 404 high density filler. That's all there is to it maine89. That's a heat lamp by the way since spring doesn't seem to want to arrive.

 

[jibes138]

That's the creepiest looking thing I've ever seen. Looks like an eye from a reptoid that came down from outer space to give you some free advice. Maybe it will be more appealing once it is painted.

 

[25yearslater]

Damn, my secret is out. Yes aliens have coached me through this process. They have shared advanced techniques and materials in exchange for the occasional alien prostate exam. OOOHHHH and out the nose comes the coffee.

 

[25yearslater]

So it's raining but at least it's 73 degrees. That means, oo baby, hull liner time. First as discussed previously the Volara (closed cell polyethylene at 1/4" thick) foam was cut and bonded to the hull using 3M High Strength 90. That should be sufficient as the high temps are low enough to keep from adhesive failure. Let's hope on that anyway. The hull liner being fitted for bonding with 3M Super 77. This product is clear so any bleed through will not show. I did test this to make sure but let's not be sloppy. So here we go. And yes this cloth is a polyester blend virtually original to the scraps I recovered after removing the interior and subsequent Ozite stuff. I will give it a good spray of Scotch Gaurd when complete.

 

[25yearslater]

OK. Well the cockpit floor has been epoxy injected. Drilling a grid around the affected area at 4 inches was sufficient to dry it out using a heat lamp. The telltale dark color disappeared as the moisture was driven out. Screwing a piece of plywood covered with polyethylene from the top clamped everything together while the epoxy cured. The plywood was on the bottom bye the way. Now for the other thing. The foam was bonded with 3M High Strength 90 to the hull. The fabric was bonded using 3M Super 77. This stuff grabs like mad so you only get one shot at it. Working in sections at about 2 feet per time made it manageable. A line of masking tape was run along the top edge prior to glue up to aid in repositioning the fabric as it is easy to distort or shift from its' best position. And just to see how this would look. The unstuffed cushions.

 

[bria46]

Your section on "closing-thru-hull-fittings". I just finished their section in the April issue of Sailing Magazine and your process of sealing the Holes was identical to their professional recommended method. And even BETTER! Great job!

 

[jibes138]

v-berth looks great

is the 3M 77 the stuff in the spray can? If it is i have used it in adding suncovers to a jib for my roller furling with sunbrella. Holds everything in place while you sew it , works great but i agree you only get one shot as working with a foam type product trying to pull it apart you would likely tear apart the foam before the adhesive joint. On two fabrics like dacron and sunbrella it isn't quite as bad...good product.

I didn't understand your post about the cockpit floor and the grid. Did you drill holes from the bottom and inject the epoxy from the bottom? These production boat builders were all hacks. Not sealing deck penetrations should be a crime. I really like the island packet idea of using a non absorbent foam for a deck liner instead of wood, eliminates the moisture problem completely maybe at the expense of weight but their boats aren't out to win races. Do you have any photos of your cockpit repair ?

 

[25yearslater]

Sorry about the delay responding. My Father in law passed away unexpectedly so we have been coping with that. Thank you Bria46. To me it just seemed sensible to apply a simple solution as the structure was never compromised. Very good to know a reputable publication has used pretty much the same technique. OK jibes. I drilled the grid from the bottom for the injection and about a dozen from the top to affix the board to the bottom. It was also interesting to note the lower skin was thinner than the top laminate so the freeze delamination occured at this area with less on the top. It is also a relatively easy process to do without the fuel tank in place. Lot's of room to work. Sorry I didn't take photos. It was just that straight forward. I used one of the WEST Systems epoxy syringes and the holes were 1/4 inch which allowed for a tight fit for the tip. I also covered the bottom of the boat with a sheet of plastic as the epoxy squirts out from the pressure when you remove the syringe. This also gives a clue that it's full as well as the squeeze out from adjoining holes. The super 77 is the stuff in a spray can. And you are right about it's adhesion properties. Fast and furious.

 

[jibes138]

do you have wheel steering? What caused water penetration in the cockpit floor? I found in my O'Day cabin top that the inner skin in the cabin ceiling was quite thin compared with the outer skin. I had some core repaired in this area but didn't cut the skins or drill holes. Instead I removed the hatch and then gouged out all the wet core that had leaked in through the turning block screws for the mainsheet. The screws were directly above a cabin light so water leaked into the light so no leakage was observed by previous owner. I bonded in strips of wood with epoxy to fill the core back in clamped it all up then re-installed all the hardware. Repair worked great and minimal cosmetic impact. That's why I was wondering about the steering if the hole for the cables could be used to gouge out the core? If tiller steered how did the laminate get compromised?

 

[25yearslater]

And the answer is: the gas fill. This was the standard cut and stuff without any relief for a waterproof barrier. The other area was the rudder tube. The area at the base was never core isolated and it was poorly affixed to the floor.

 

[jeagles]

I have a mysterious diesel leak into the bilge on my ODay 31. Cannot find source. The small tank option may be the answer. What is purpose of return line to tank?
Jim

 

[bria46]

The fuel pump on a diesel engine delivers more fuel to the injectors than is required. The return line to the fuel tank is to take the excess fuel delivered to the engine and return it to the fuel tank.

 

[25yearslater]

While we're on the topics of tanks, here is the new one. It is less length than the old one by 1.5 inches. This will require a larger seat rail for it to sit in it's original cradle. Also we have the cushions underway with foam from www.foamdistributing.com and I might add the HD36 is plenty firm. Cut with an electric carving knife to shape and you are ready to stuff it in the covers. This is inexpensive enough to replace at the earliest hint of mildew but bears noting it isn't flame retardant as some of the higher cost foams. Lastly the rudderpost was ground out with the Dremel and a carbide burr and filled with epoxy and high density filler as a result of delamination of the cockpit floor.

 

[Panta Rei]

Looks great Joe... You found a real winner for a foam supplier. Free shipping too!
Fire retardant; the way I see it the cover, sheets, and blankets would need to be burning before the foam caught fire. Not worried about the foam at that point.

So how close are you getting?