Hatch/fiberglass repair question

[speakrdude]

I'm sure quite a few have tackled this before.
I am replacing/reinstalling the 20x20 hatch in this 88 300 Weekender. There were areas of wet wood and rot in the core on the sides and lower section of the opening where it has been leaking over the years. With a drill, a screw driver, and a shop vac, I was able to remove all of the damaged areas down to good solid wood.
My question is, other than the obvious answer of cutting new pieces of plywood and coating all in a good thickened epoxy resin, is there a better way to fill the voids, especially the "uphill" areas where I wouldn't be able to get resign to flow on its own? For example, can this acomplished with a good expanding foam of some kind and then new wood around the openng?
Just looking for some suggestions. Sometimes I overlook the obvious, you know, like the forrest and the trees.
Thanks

 

[88dancer300]

Need pics of your repair area.

 

[tobnpr]

No, don't think you're missing anything...
Wood is cheaper than epoxy, so trying to fill large voids with epoxy isn't cost effective, and large quantities of epoxy exotherm too rapidly which makes for multiple applications.

Other than wood, you could use a synthetic structural core like Coosa board, but why bother with the expense. If the areas you're trying to reach are deep, West System has fillable (and reuseable) "caulk gun" tubes that work great. I've used them extensively for glueing fillets, but you could attach a tube to the end to inject quantities into hard to reach, deep gaps. Expanding foam, no matter the type, is not structural.

My main advice is to be SURE you've gotten to completely sound, and DRY balsa. I spent two years chasing rot on my '72 Chris- if you don't get every single spore out, and get down to completely dry wood, it WILL be back. Good luck, my $.02

 

[speakrdude]

Pictures, I have...

This picture shows the new wood cutout to fit the ares of bad wood that was removed. The top edge is minor surface area only.

Close up of above..

This is a picture of where the old windlass mounted. I did some repairs and small amount of dryout and wood removal and then repair. First with unthickened epoxy for it's flow ability with a couple of wood plugs installed in the holes, and then thickened epoxy for structure.

These are the new 12x12's Installed in their spots. Someone please tell me. How do you caulk around the back of these if you cannot remove the lid? A long snout I suppose?

 

[speakrdude]

Yeah, I already use West epoxy in a syringe. The thickened epoxy kicks really fast so I usually mess that one up. I suppose I could mix it up a little colder and then thicken use a larger syringe (Vet. supply) and the hose trick sounds cool.

I read somewhere about a mixture of antifreeze and somekind of chemical (ant or roach poison? I can't remember)that will kill the mold spores. But then you have to deal drying that liquid. Anyone ever hear of that one? I was a section called "Chemotherepy for rot"

 

[tobnpr]

Yup- glycol (the green stuff) antifreeze supposedly kills the mold spores. I did use it on my CC in areas that could air dry. Might have read about it on the "rot doctor" site, can't remember for sure...

 

[speakrdude]

I found it...

http://www.angelfire.com/nc3/davecarnell/rot.html

 

[AKBASSKING]

I had the same issue when I redid my hatches. I did a thread about it. I used a wood filler made by minwax. It is epoxy base. Add some hardener to it, mix it good and fill the hole. It dries fast. Then you can sand it clean and it is real hard. I could only find it at Lowes or Home Depot. I had to get it at an Ace hardware store.

Once you get that all prepped and ready to install your hatch apply a generous amount of 5200. If you are installing the original hatch, make sure you dip the screws in 5200 to seal the holes. This may be the reason you got water intrusion in the first place. If you are installing a new hatch pre-drill your screw holes to prevent damage to your gel-coat and the screw pattern is different, fill in the old holes with 5200.

 

[tobnpr]

I found it...

http://www.angelfire.com/nc3/davecarnell/rot.html

Good article.

The antifreeze def worked for me. I wasn't aware that it would actually penetrate finishes without damaging them...

Bottom line, though, is that if the wood is structurally damaged, it needs to come out. You can't soak it with antifreeze, and then try to fix it with epoxy.

But in your case, with all the rotted wood removed- painting the remaining exposed surfaces (maybe use an artist's paintbrush that would be long and skinny enough to get all the way back in there) would kill the remaining spores. The epoxy won't bond to the wet wood, but that shouldn't affect the integrity of the repair IMO. Good luck, let us know how it goes.