Fiberglass locker repair

[G0ri11@]

One of the lockers on the port side of my boat's cabin is cracked along its wall (see pictures). The biggest issue with this is that it won't support weight when using it climb in and out of the cabin. My plan is to screw a piece of 3/4" plywood to the back of it to stabilize it, but then can I just fiberglass over that to cover the cracks and then sand down until flush?

I haven't done any fiberglass work before, but it seems like this shouldn't be too terribly difficult. Would I also need to glass over the part of the plywood inside the locker? If so, would it make more sense to fiberglass cover the wood first, and then screw it in place and try to "fuse" the wood with the original wall so that it looks (sort of) nice?

Advice appreciated.

 

[rgranger]

Fiberglass is very forgiving. If you screw it up, grind it off and try again.

The leading edge (the flange) of your locker that is not broken off (red circle) can be used to make a female mold.

Take a sheet of plastic and cover over that circled flange. Then wet out some fiberglass cloth and lay it over the plastic and existing flange. Once the resin sets, remove the cloth from the plastic sheeting and you now have a mold. Next put a sheet of plastic inside your new mold and lay up about four or five layers of epoxy wetted fiberglass cloth and let it set. Pull it out of your mold and you now have a perfectly formed piece that will fit your exiting flange. Take a hack saw and square off the edges of the broken flange, fit your new piece in (I'd add some JB weld along the edges and tape it in place until the JB welds sets. Then from the back side you can add a few layers of fiberglass cloth to overlap the edges to add strength. Sand smooth, paint and you will never know it was broken. If something goes a little wonky, cut it out... or grind it down and try again until it looks right.

I have done many small repairs on various boats and I find epoxy resin to be much easier to work with than polyester resin. I usually buy my resin from Jamestown Distributors.

 

[rgranger]

.... another very useful "trick" when working with wetted fiberglass cloth...

Get some thick plastic sheeting from Lowes or HD. Cut out a square of the plastic and lay it on your work bench. Put some painter's tape on the edges of the plastic with the sticky side UP. Lay your wetted fiberglass cloth on the plastic and lay up as many layers as you plan to use... It is generally better if the layers overlap in size so put the larger pieces on first and the stack the smaller pieces.

Now take your sheet of plastic with your 3 to 6 layers of wetted cloth over to the spot on the boat that you are repairing and using the painter's tape, tape the sheet of plastic in place and with the heel of your hand press the fiberglass cloth into the area you want to repair. The tapped sheet will hold it in place while the resin sets.

 

[dlochner]

The method @rgranger suggests will work, I'd add a few steps. Grind off the the gel coat along the entire front edge and a little of the glass. Put the replacement piece in and use some thickened epoxy in the joints. You'll have to figure out how to hold it in position. A few clamps and plastic wrapped boards will work. Epoxy does not need much clamping pressure.

After the patch hardens a bit, but while it is still "green" meaning it is firm but soft, a finger nail will dent it but not be sticky, Lay up another layer of glass across the top and one under the lip. This will strengthen the lip. when all is cured and solid after a day or so. Sand, fair, and gelcoat or paint.

In a recent issue of Cruising World Steve D'Anotonio wrote about fiberglass repairs. Use epoxy, not polyester resin. Polyester has decent primary bonding, i.e., it bonds well to itself before it completely cures, but has very poor secondary bonding or adhesion. Epoxy has very good secondary bonding, or mechanical adhesion. Don't use resins that you buy at an auto parts store. Use West System, Total Boat, or System Three. You can get these at Jamestown Distributors or Defender. If you call Jamestown Tech support they will guide you with right type of cloth and other sound advice.

One other option would be to find a dowel of the right diameter and use thickened epoxy to hold it in place and then build up the outer profile with epoxy and fiberglass.

The West System website has a couple of free ebooks about epoxy repair. Worth the read.

 

[rgranger]

... If you call Jamestown Tech support they will guide you with right type of cloth and other sound advice....

 

[dlochner]

After the patch hardens a bit, but while it is still "green" meaning it is firm but soft, a finger nail will dent it but not be sticky, Lay up another layer of glass across the top and one under the lip. This will strengthen the lip. when all is cured and solid after a day or so. Sand, fair, and gelcoat or paint.

This is across the entire opening, not just the damaged area.

Do not apply epoxy over gelcoat. The epoxy will adhere to the gelcoat, however, gelcoat does not have great adhesion properties, thus the repair will not be very strong.

 

[ggrizzard]

"Do not apply epoxy over gelcoat."

 

[G0ri11@]

Here are some pictures from step 1, my attempt at forming the mold.

 

[dlochner]

Here are some pictures from step 1, my attempt at forming the mold.

Looking good so far!

 

[rgranger]

Fantastic! You are now the new resident expert

 

[G0ri11@]

The mold turned out surprisingly well. I'm starting to think this might work!

I laid 4-5 sheets on plastic over the mold today. So, hopefully this will yield something that can start to fill the gap.

From the instructions above, my plan is to take what comes out of this mold and put it inside the locker and use some thickened epoxy to glue it up against the inner wall of the locker. Then I'll probably lay a few more sheets of fiberglass over the top and outer portion, then sand that back flush.

Depending on how robust the "lip" seems, I might try to tuck a few more pieces underneath that curve and hold them in place with the dowel trick mentioned above.

I took some pics today, but it's impossible to tell what they're showing.

 

[rgranger]

The mold turned out surprisingly well. I'm starting to think this might work!.....
Depending on how robust the "lip" seems, I might try to tuck a few more peces underneath that curve and hold them in place with the dowel trick mentioned above.

Sounds like you have caught the fiberglass bug...
Now you will start making bird houses and cookie jars and who knows what...

 

[MikeHoncho]

would it be possible to mill some hardwood molding to cover the area that is missing and make it look like a foothold to step out?