seeking input on soggy deck

[capejt]

Hi all!
In the process of restoring a 79 H33, I came across a very soggy section of deck over the head. Apparently the previous owner had installed a solar powered vent fan without properly sealing the wood core around the hole. Though drilling test holes around the opening, and by scraping out the goop that was once a wood core, I find that the rot goes about four inches back from the opening (almost full circle).
Now, I know the usual route here is to cut out the top layer of glass, replace the wood core, then replace the top layer of glass, but I was thinking that maybe, if I gave it some time time to dry out I could simply fill the void with "Kitty Hair" or similar filler. I really would like to avoid all the cutting and reglassing if possible.
Any thoughts? Thanks!

 

[BobM]

From what I have read the reason for the core was to add stiffness cheaply due to the expense of building the same structure out of resin. I wouldn't do an entire deck that way, as your boat wasn't designed to have another 500+ pounds of resin that high above the waterline, but I woudn't think that a small section would be a big deal. I did something similar on a smaller scale when I found about a inch of rot around the cockpit drains on my old boat. It seemed to work fine, but I never took it apart again after that.

 

[Tim R.]

No need for kitty hair. Just use thickened West System epoxy. I use 404 thickener.

 

[Warren Milberg]

I had a small section of wet/soft foredeck on my old C&C. I drilled a grid of 3/8" holes into the deck, about 3/4 of the way through using a jig on the drill to keep from going all the way through. I used a bent nail to try to gouge any wet coring. I also attempted to suck out or dry out the area using both a high powered wet/dry vac (didn't have enough moisture to work) and using acetone and then a hot air gun. When I thought it was dry enough, I injected unthickened West System epoxy into the holes, waited for the epoxy to settle a bit, then injected more until the holes were almost, but not quite, full. When the epoxy set, I filled the top of the holes with white MarineTex. This seemed to work well for an area a little less than one square foot. Not sure if it work be the solution of choice if the area were larger.

The West System Epoxy manual has a good description of this task.

 

[kendall]

Think is good for small areas, but I wouldn't try it on larger sections. The problem with that approach is that you have no way to ensure it's clean enough for good adhesion, so you may still end up cutting it out and having to dig out whatever you filled it with.

I recently repaired a small section on my deck with 3/8th ply, re-using the skin and it took less than a day start to finish (not counting repaint etc) I used ply because I wanted the compression strength, but to avoid wicking issues I cut the ply into 3x3 inch squares and spaced them about 1/8 inch to avoid wood to wood contact, then filled the spaces between with thickened epoxy. (my reasoning is that if water does get in, damage will be limited to a 3x3 section) It's very rigid now, and didn't seem to add much weight. Have another section on the other side that did feel ok, but in comparison to the repair, it leaves something to be desired so I may do the same on that side.

Ken.

 

[Blitz]

No need for kitty hair. Just use thickened West System epoxy. I use 404 thickener.

I agree totally - this is the way to go. Use a bent nail, allen wrench or a right angle pick to remove all of the wet material and ensure it is dry. As suggested here, using a high powered shop vac as you go will help it along. Start with the unthickened West System epoxy to wet the core, then inject the thickened mixture (thickened to a peanut butter consistency). This is all described best in the West System Epoxy manual:

http://www.westsystem.com/ss/fillers-and-additives/

 

[capejt]

THANKS! It all sounds good. I thnk it's beyond the "drill & filll" method though. The ere's a gap bteween fiberglass layers of about an inch, and as noted before, it spreads aboiut four inches from the edges of the hole the vent came out of. I like the idea of thickened resin though. I think I'll give that a shot. Another idea I had was to fill with that foam insulation stuff. Any thoughts there?

 

[Blitz]

Another idea I had was to fill with that foam insulation stuff. Any thoughts there?

Foam is not strong enough.

Also - use syringes to fill the epoxy mixture into the gap - be carefull to remove any air pockets

 

[Ross]

I presume that you have a 3-4 inch hole to work through. You ought to be able to rake the rotted wood out from the hole. I would use a sawsall blade with lots of tape on it for a handle. When you are satisfied that you have it as clean as you can get it. Saw out some blocks that are just thick enough to slide into the gap. Dip each one in epoxy and slip it into the slot. Use a short, small scratch awl to shove them around and get them as closely packed as you can. Possibly even pre cut the whole batch and dry fit them to check the pattern for placing them. You will be working blind here and you don't want big gaps between the blocks. Consider a 1 inch square stick cut into many pieces about the length of the space between the skins. If the epoxy is about as thick as mayonnaise you can probably get close to 95 percent fill on the first try.
Edit to correct punctuation and spelling and to add the following:
If you also cut a few small wedges for the edge of the opening, inserting the blocks will be easier. Get rid of the wedges when the last block is in place. Protect the surfaces under the repair.

 

[capejt]

A big thanks for all of your help. What I ended up doing was to seal oof the void from inside the fan hol, then injected west systems epoxy thickened with colloidal filler through hole drilled in the deck surrounding the rotted area. It seems to ahve worked out pretty good. The old "hammer tap" test shows the deck solid where it wasn't before.

 

[Ross]

Check it in a year and let us know if it held. Thanks.