Drying out the stringers...how much?

No permission granted. you should however drill or do whatever you can to let the water escape from the stringers and reglass the holes. If you shortcut this now, you'll be back later to finish it and it'll be bigger issue. Is boat in direct sunlight? keep a fan or somthing blowing on it 24/7 with the tarp off. The dehumidifier will take a while.....

Drill the holes and inject acetone into the timber, the acetone evaporates very fast and will draw the moisture with it,thats how I did mine 5 yrs ago. You will need to keep repeating the process a few times.

Dont rush the job, you will regret it

Good news!

I took the above advice to heart and drilled a few exploratory holes. Didn't have to go far before I got to light brown, unrotted wood. And it was a bit drier than the wood close to the bolt holes.

So I don't think it will take much longer to dry it out. And I'm not going to fill it back in until it's nice and dry.

Thomas

David F,

That's interesting that you can thin epoxy with acetone. Does it affect the final strength? Do you have to adjust the amount of hardener you use? I'm just wondering because it seems that it would have to react with something or else it would have to somehow evaporate out of the mixture.

The other thing about these products that are supposed to soak into rotted wood, besides the consistency, is that that their cure times are longer than usual. Anyway, the West Marine version of Git-Rot doesn't have acetone but it does have diacetone alcohol. I'm no chemist so all I know is that the molecule is a lot bigger than acetone. Here are the ingredients listed on the containers in case they mean anything to anyone:

Resin:
------
Bisphenol A diglycidyl ether resin
Propylene carbonate
Diacetone alcohol
Alkyl glycidyl ether

Hardener:
---------
Triethylenetetramine
Dipropylene glycol monomethyl ether
Bis (dimethylaminomethyl) phenol
2,4,6-Tris (dimethylaminomethyl) phenol

Interestingly, the resin component doesn't really seem thinner than regular resin when you pour it out but after you mix it all together the result is definitely thinner than normal epoxy. The hardener might be thinner than the usual hardener.

Ok, I have a degree in Chemistry but never heard of diacetone alchol so I searched the Net. It is a bigger molecule than acetone...so it will be slower to evaporate. The boiling point is 168 C (334 F). Water boils at 100C (212 F). So it really won't help evaporate the water. Acetone certainly will!

The best part is this molecule has twice as many "handles" to grab on to a water molecule. Acetoe has an oxygen atom hanging out there which the hydrogens on the water are attracted to (forgive the dangling participal). Diacetone has an oxygen as well as an "OH" (alcohol) hanging out there for a water molecule to grab on to (again with the dangling participal). This can do two things, one, allow the diacetone to get "sucked" deeper into the wet wood (being attracted to the water molecule) and two, the water will be attracted to the OH leaving the oxygen molecule free to bond with the polymer (like the acetone, or methyl ethyl ketone).
I'm not a polymer scientist, but that's my best guess without doing futher research. There is also the possibilty the diacetone would be metabolized by the wood rotting fungi to a toxic substance and kill the fungi (I'd have to check--or you could ask the manufacture).
Anyway, unless you kill the fungi, they will continue to "eat" the wood. Even if you seal off the hole with epoxy.
TLeed...If it were me, I'd take the additional step of killing the fungi that is rotting the wood. If you have the time, fill the holes with antifreeze and let it evaporate. The antifreeze will kill the fungi and anything else that's eating the wood. This will set you back in terms of drying out the wood (which I know you don't want). Check with the Git Rot manufacture. If their product doesn't kill the microorganisms, I'd do the antifreeze or a boric acid treatment. This link is a good read:
http://www.angelfire.com/nc3/davecarnell/rot.html
If you check with the Git Rot manufacture, post the results, I'm curisous.
Good luck
By the way, you could do the repair and get back in the water then address the rot issue (pour antifreeze in some holes drilled near the repair, then fill with epoxy) over the winter.

Jimbo,
I think you may have stunned the world. Are you referring to automobile antifreeze? To the best of your knowledge will antifreeze completly evaporate without leaving any harmful residue that will prevent epoxy from bonding to the wood?

By the way, I care and I would like any additional info on the subject you feel like sharing. Thanks!!!

All I want is to go vroom, vroom and splash in the water, and you guys are presenting advanced lectures in polymer chemistry! I'm so impressed!

Seriously, this is very interesting. I have been soaking my holes down in with acetone the past couple of days. Three are dried out nicely, and the third is the slow one. Dehumidifier is still going.

Antifreeze? That stuff will never dry out!

Boric acid. Now I could manage to try that. That's an ingredient you find in eye drops for pink eye, I think. White crystal that readily dissolves in water. Could dissolve it in the acetone.

Thomas

Oh ye of little faith...
Mold does need moisture to live. Drying everything out will kill the fungus, but spores will be left behind. When the moisture content gets right (and it will, or you wouldn't have had this problem in the first place), you've got a lot of spores ready to develop back into wood eating monsters.

Antifreeze won't really evaporate. It will be absorbed by the wood.

My best guess is the antifreeze will not significantly hamper bonding epoxy to the wood. Dumping boric acid or borax in the holes probable would. I'm slightly concerned about boric acid weakening the fiberglass.

Acetone will kill fungi, but it would take a lot more acetone alot longer to kill them than ethylene glychol. The antifreeze is toxic at a lower dose. Plus the acetone evaporates.

Here's some research on epoxy bonding to wood treated with antifreeze and boric acid.

http://www.maritime.org/conf/conf-reynolds-mat2.htm