How to patch boat?

[JeffM]

I'm guessing no one will be very surprised by this question.  I have a hole in 9mm okume in the bottom and in 6mm okume in the side.  The one in the bottom was immersed in seawater for 4 days, give or take.  I'm expecting I'll make the holes rectangular and butt in patches with glass on both sides.Come to think of it, maybe diamond shaped would be better in the side, which has a slight curve.)  What I don't know is what, if anything, to do about the water that infiltrated the wood, and whether the salt will have any consequences.  (The boat was rinsed, and has now had 4 days drying out.)

[Frank Hagan]

Make sure everything is dry before you patch it.  If you trap any moisture, it could rot (I've heard that Okume is not very rot resistant).  Butt patches with glass will work fine, but Ray's "finest kind" leanings are probably better advice for a nice looking patch.

[PAR]

Rather then go through the trouble of making fairly accurate scarf bevels on 8 edges, just use a grinder.

I make these types of repairs all the time and it's just not worth the trouble of scarfing in small areas.

Cut the damage out, back to good wood, then with a grinder, belt sander or whatever, angle the edges of the repair area considerably. Make a repair piece with the same beveled edges. Not a scarf, but the opposite of a scarf, with the bevels facing away from each other. Position the repair piece inside the center of the hole, preferably with tape or plywood lightly tacked to the inside, to keep ooze out from pouring through the seams.

Wet out the pieces and bevels, apply fabric and thickened epoxy, enough to insure it's strength., leaving it slightly below flush. When cured, fill and fair to suit. If you're good, you can apply a piece of plywood (covered with packaging tape) to the outside too. Clamped or screwed to the piece on the inside of the boat, your surfaces will be nearly fair when removed. This requires a good bit of forethought and planning, which most novices don't have, but it's not that tough to work out and can save a good bit of fairing work.

[JeffM]

Thanks, all--Paul especially for the details.  Paul, any clues about knowing the wood is dry enough?

[PAR]

Without a moisture meter it's tough, but plywood doesn't soak like solid lumber and dries fairly quickly.

A few tricks to speed it up though: steam it or acetone it. These may seem counter intuitive, but they're not. Steam will dry out the piece very quickly (in a day or two) and acetone will draw out the moisture, but depending on moisture content may take longer.

I use steam to "season" small diameter pieces all the time. Of course, thickness matters (ask your girl friend), but generally as soon as the piece seems dry to the touch after steaming, it's ready. This usually takes a day or two. I have one of those floor steam cleaners (Scunci steamer) and it kicks butt on small pieces that I'm trying to bend or repair dents in wood, etc.

http://www.scunci-steam-cleaner.com/

It used to be the other half's, but I got caught using it on a piece of coming trim and had to buy her another one.

I suspect an iron on the steam setting will do a fair enough job too. Saturate the crap out of the area, then let it cool. 24 hours later, hit the surface with sand paper. If it doesn't fuzz up, you're probably good to go.

[Andrew_Butchart]

I don't know if it works on wood, but to dry electical parts, people will often soak them with methanol (available at farm supply stores).  This changes the evaporation point and draws the water out as it evaporates.  Just have good ventilation - it will be safer than Acetone at least.

I had a hole in the bottom of my pirogue where the dolly punched through due to a heavy snow load.  I just used my jigsaw and cut out the damage in an odd shape.  I then held replacement plywood on the other side, transferred the shape and had a patch.  To secure it, I attached it to a larger piece, slathered everything with PL Premium (expands as it drys) and screwed up through the bottom into the patch piece.  From the bottom, it's nice and smooth, or will be when I get around to finishing it.  On the inside of the boat I have an odd piece of plywood on the bottom with no obvious purpose, but it shouldn't leak ....

[Konrad]

I've seen cheap moisture meters at Menards for about 19 dollars.

Or you could contact a local home inspection company and see if they'd stick one on there for free, assuming you'd tow the boat to them.

Very likely that their meters will be better than the Menards version.