Water intrusion into balsa core

Screw choice: I use pan head SS sheet metal screws--the wood screws are tapered and not much thread at the upper part of the shank. Occasionally I'll use flat head screws, but usually with footman loops, or other fasteners which have a beveled edge that the flat head sits flush to.

I would be sure all areas are filled with thickened epoxy--not just thin or penetrating epoxy. At this stage you should be able to sound out, with a plastic screwdriver handle (phenolic hammer is the classical surveyor's tool, but the screwdriver handle works as well.) Where there is the delimitation or wet core, you want to remove all of that. Not sure how much that will be--until you have sounded and drilled, etc.

I would glass over what ever were the cleats which held the tanks in place. That way there are no screws necessary. Starboard does not glue well. I have been trying some with "G Flee, and under cutting in a "Y" shape with a Fein type of saw. Seems to be working well. I also flame harden the Starboard with a propane torch.

You can glass in blocks--better than just epoxy under--but I have some blocks which are epoxied to the sides of the hull, and some which are glassed over. Both seem to be doing equally well at this point.

You can buy or make fiberglass "L" brackets You could use Starboard as a form--just put a little wax or teflon on the surface to be sure that the epoxy or polyester resin does not stick. Mold up what you need. If you use glass cloth and mat it will set up fairly quickly--then you can epoxy this to the floor, and have a permanent bracket for the facing boards.

I use heat guns (2 heats/fan speeds)--my wife draws the line at using her hair dryers. Just be sure you open it up enough. If there are large areas then get some core material, and put that in.

Anything you can glass in to screw to, is going to be better than the Balsa Core!

Thank you for asking about my projects--the boat is as ready as it is going to be in the summer of 18! Ready to roll to the Rivers. The side steps came out well, and no evidence of water intrusion. I am not so pleased with the Loctite PL Marine, which was touted to be the same as 3M 4000. I did some of the area where the seal around the removable floor section (fuel tank access) and around the steps turned yellow, and the adhesion to the fiberglass is not as good as I wanted. This area is covered by the Deckadence vinyl loop carpet, and with all of the rain we have had, when I pulled up the Deckadence carpet, There was some moisture trapped in the forward edge of the cockpit. I like the Deckadence; it looks better than the fiberglass cockpit floor. All of the dirt goes thru the vinyl loops, and it is all cleaned up in one short period of time. I pulled the Deckadence, and washed it from both sides, to get any dirt or debris out. After it and the deck was dry, the carpet was re-installed.
 
If I get wet holes say in a 5 inch area around the mounting holes do I just drill say ¼ holes throughout the area and fill with epoxy? Then paint it with something? I just drilled the mounting holes with a ½ bit and 5 of the 7 were wet. If you cut a square out of the top skin to replace a piece of core I guess you just glass it back down and fair it with gel coat or paint it? Thanks for the help.

I’m hesitant to explore the area forward of the tank. I hate to not be able to match the rest holes with the cockpit and they be visable. Prob needs to be done though.
 
If I get wet holes say in a 5 inch area around the mounting holes do I just drill say ¼ holes throughout the area and fill with epoxy? Then paint it with something? I just drilled the mounting holes with a ½ bit and 5 of the 7 were wet. If you cut a square out of the top skin to replace a piece of core I guess you just glass it back down and fair it with gel coat or paint it? Thanks for the help.

I’m hesitant to explore the area forward of the tank. I hate to not be able to match the test holes with the cockpit and they be visable. Prob needs to be done though.
 
So it's not as bad as I thought. Looks like now I just rout out the bad balsa and fill with thickened epoxy? Any tips on finishing it so that it looks like the hopes were never there? Even though most will be covered by the tank. Most holes only had about an inch of wet balsa, the exception being the enlarged hole where someone screwed down at an angle.

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Brandon, Just looking through your photos. Looks like you are doing a good job. Question? Was there not a bilge pump on that cockpit sole, aft, between the tanks? I didn't look like there was. I think there is a "sump well" or depression there, midship, for locating one. Maybe I just missed it.

Harvey
SleepyC :moon

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Hey Hardee,
There is a depression there and I plan to install a second bilge pump, either electric or manual. I have a sump to starboard of the companionway door. The rear bulkhead straddles it with half in the cockpit and half under the stove. There’s a bilge pump in there.

The good news is that the screw holes for the battery hold downs and the port side tank were either dry or had less than a ½ inch of wet core around the holes.

The area on the starboard side around that problem screw hole is about 6 inches x about 2 inches in a linear fashion. At this point it may be easier and a better fix to cut the top skin off and just fill the whole area. I’m still working on it though and think I have the most wet stuff out. I may be able to let it dry out and just fill the holes I’ve drilled. I just want it done right.
 
OK I'm done for the day. You can sort of see the outline of the wet core from the screw holes. The outermost holes were dry. I think I have so many holes drilled that I don't need to take the skin off. I filled the dry holes and I think I'll just re-screw the hardware down into the center of the epoxy plug and use 4200 underneath. Do you guys think that's a solid plan? The issue with glassing down the runners is that the forward partition sits and is screwed in aft side of the runner. So to take the tanks out you have to be able to remove that forward runner in order to pull the partition off as one piece. The tank sits up against the screws that hold the partition to the runner and it looks like that partition gives the tank a little forward stability so I want to keep it.

I also found some rubber liner at the Home Depot thats uses to line the bottom of showers, debating whether to put it under the tank for a little abrasion resistance. Thanks for the help and the forum, this place is a great resource. This repair, including 6ft of fuel line will end up costing just over $200

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Snider":23lhetl9 said:
...

I also found some rubber liner at the Home Depot thats uses to line the bottom of showers, debating whether to put it under the tank for a little abrasion resistance. ...

Mine doesn't have anything under the tanks. If they are securely attached, they shouldn't move so there should be no abrasion.

Look at the bottom of the tanks and the area where they sit to see if there is any evidence of existing abrasion. I don't see any in your pictures. You might be fixing something that isn't broken. However, if you feel more comfortable doing something then go ahead.

Just check that what ever you put under the tanks is gasoline resistant/proof. Don't want anything that will turn in to a gooey mess if gas does happen to get on it.
 
I did the same project 2 years ago. All my gas tank screw holes were dry and well siliconed until I got to the very last one. I found no evidence of silicone (maybe they forgot?) . This one screw hole had rot and moisture as far away as 12".

Dont think just because you do a light exploratory hole and find dry balsa on top, that you are out of the woods. The majority of mush I found was at the bottom, (pooled against the outer hull glass), and the area became smaller the higher up I explored. Similar to a funnel shape.
 
In your case, I would just fill the holes and get some paint which js close to the bilge cover, "
Bilge Coat is a product frequently used. The "pattern on the bottom is basically rolled out thickened gel coat. I did replicate that pattern on the cockpit floor rolling it out.
 
Thanks Bob, I'll do that.

Capt Meares, good points. I drilled the holes all the way through to the outer fiberglass skin. If by mid week after the dehumidifier has been running and intermittent blow drying I still find moisture I'll just cut the top skin off and tackle it that way. Ultimately I just want it bullet proof.


Ssobol, You know there wasn't much abrasion on the bottom of the tanks. There was some along the edges though. It was hard to tell the cause, it could have been where they hit it with something right after manufacture to get the rough edges off. That's what I suspect. So you may be right, there may not be a problem there. I was hoping a little rubber between the tank and floor might help from dirt and stuff getting under there. I was planning to cut a piece of that rubber and drop it in a bucket of gasoline to see if it would hold up. Even if it does I may just skip that step and chalk up the lost $30 to a bad idea.
 
Finished up with the cockpit repair yesterday. All in all it was a pretty quick and easy fix just working about 4 mornings while the kids where in school. It could probably be done in a long day if you didn't have to wait for epoxy to cure. Thanks for the help here, now on to the lazarette hatches. :D



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I am about to embark on the same project that Snider did.

I am going to use this West Systems kit:

https://www.amazon.com/dp/B07JGJ84Y4/?c ... _lig_dp_it

My question is can I use the 206 hardener if temperatures are below 60 degrees F? I looked at West's chart and they say the minimum temp is 60. I could use the 205 hardener, since it has a minimum temp of 40.

Right now, our temps during the day are 45-55 and at night can get to the high 30s.
I just want to have enough working time since this is my first go at fixing core issues around the fuel tanks and redoing the core around the fuel fills. I will also tackle all the other deck penetrations, too. The hatch leaks around the perimeter so gotta do that one, too.

Any suggestions are welcome.
 
Patrick,

Glad I could help pass the word. I'm sure Everett is probably your closest trip to West Marine, I however had used Anacortes without issue for my purchases. I had all of the pages for the products I wanted to purchase ready to go at the register and it was a no issue process there.

For anyone looking to purchase there here is the policy. https://www.westmarine.com/CustomerService/Price-Policy

As to my progress, I've been on the road since early January but will be home soon. Right before I left, I pulled all the deck hardware, drilled and filled the holes since I wanted to not have the balsa coring put in in the middle of winter. I also ordered the aft laz hatches, they arrived the day I left, but my wife did a video call and test fit them for me and they look to fit perfect.

I have a little road block it seams now though.... When I finish this message I'll be sending out a blanket message to all distributors and to the C-Dory factor itself. It seams that there is a shortage of Balsa... Carbon Core, the company that I was lined up to purchase balsa from advised me that they didn't know if or when they would receive stock again and since I'm looking for 1.5" my chances were slim... Not what I'm wanting to hear. :evil:
So if anyone has a verified source, I'm all ears!!!

Best of luck on your work and the upcoming fishing season (assuming we get one!)

R/
John
Scallywag
 
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