I have found that after filling a hole with gel coat, I can keep it quite flat by taping over it with a piece of scotch tape. Remove that tape after the gel coat dries.

regarding the previous message, my address:
eroise@snet.net

I repaired a 2'x4' soft spot in my forward deck about 2 years ago. I cut out the spider-cracked deck from above, peeled it and the crappy balsa off and replaced the hole section with new balsa core 2part expanding foam and fiberglass laminate. don't approach from below unless your a perfectionist, its a royal pain in the arse. I finished it off using non-slip mix from home depot in gel coat.
you can see the patch if your standing on it, but it's solid. I posted how I did it here and they deleted it when they redid the web-site. If anyone is interested, email me and I'll email a copy.

Add to the recommendations: WEST System (Gougon Bros.) has an excellent manual that talks about all these techniques- can be has at E&B/WEST Marine (no relation to the WEST System line of products. You really do not need the BIG manual- they have a pamphlet (included with their small repair kit?), and (even better) these tachniques are all online at the West system site. very good info by the way.

http://www.pyacht.com/west_system.htm

Tony,
Paul's post is right on! I have done this in the past with great success. I would only add that you tape around the hole ( or drill through the tape ) before applying epoxy / microballoons / gelcoat. This will make the cleanup much easier, and if you don't prefer the "concave" look will aid in sanding your application down to deck level with minimal damage to the deck! Good luck and best regards!
________/)/)__/)_/)/)_____/)_/)___/)_________

The process of sealing the penetrations in the deck is not that difficult.

The system can and will work for any existing or new holes, filled with silicon, 5200 (yuk), caulk, etc. Make sure you drill out underneath with a bit large enough to clear all the old sealer.

I recommned you use some West System epoxy(or equal), you can add a bit,(you still want the epoxy mixture to be thin enough to soak into the core) of high density filler or colloida silica, and use plastic syringes to fill the holes.

For new or old hardware you then drill out the proper size hole in the epoxy washer and re-bed. For holes that are not going to have hardware in them you can follow this.
After Cure:
1. Use a countersink bit to drill into the epoxy and just cut the gelcoat around the hole. This gives a good bonding surface for the new gelcoat.
2. Mix some gelcoat to match your deck color and drop it into the holes with a mixing stick. Fill the hole to flush and as the gelcoat cures it will shrink slightly to a concave shape which is the least revealing.
Note: Be patient with the color match, and don't be afraid to toss a batch if you can't get it right. It is not easy but can be mastered. If you miss on the color badly, recountersink and try again.

The results of doing this repair are excellent. You end up with the deck sealed and the gelcoat repair makes a world of differenc visually. It doesn't look like the boat was hit with a shotgun.

Good Luck and contact me with questions at scalispa@umdnj.edu

Happy Sailing;
Paul Scalisi

This has been quite useful. I have a older boat, not much damage but a lot of holes with temp plugs of 5200 etc. Is the process for fixing these the same as described? Also is this method best for a new mounting? When epoxy is talked about, do you mean resin? Is any filler necc? Thanks I've not worked much with these types of materials.

Hey Paul.... wanna come work for me?
Or maybe me for you?
Jonathan

To solve the problem/cause is a project you should undertake with the repair. Since you just bought the boat and you don't know when the deck hardware was bedded, I would consider rebedding all of the deck hardware. The process is this.
1. Remove all old hardware, replace it if its beat.
2. Using a drill bit 1/8" larger than the hardware fastener drill from underneath up until you hit the deck skin, you'll feel the difference in resistance of drilling balsa core vs. fiberglass. A drill collar helps prevent going through the deck. You can pick any wet core out of the hole with small screwdriver or exacto knife.
3. Allow the boat to air out and dry for a day or two.
4. Seal all the holes from the bottom with either duck tape or modeling clay.
5. Inject epoxy into all the holes until they are full. Keep filling the holes as the core will absorb quite a bit of epoxy. A small metal wire or pin is helpful in popping air bubbles in the epoxy.
6. After curing redrill the holes from above with the proper size bit and re-bed.
You now have an 1/16" epoxy "washer" around every bolt that will prevent future damage to the core. Even if a piece of hardware leaks it should not damage the core since its sealed in epoxy.

Its not that hard to do and its worth a great deal in preventative maintenance.

If you have any questions please feel free to contact me at scalispa@umdnj.edu.

Happy Sailing;
Paul Scalisi

Without writing a novel, some ideas. You need to determine if area is just wet (no delam, skins attached to core) or if core is rotted. If core is shot then you should recore, if just wet, then dry out and seal. If deck skin is in good shape then repair should be made from below (inside) but this means fighting gravity. If you have to replace core it is best done via vacuum-bag (more reasons than I can list here for this) and not really all that hard to do. If core is just wet, then drill lots of holes from below, use heatlamps or just time, and dry it out. Then inject resin to fill holes and patch skin surface. Obviously a little more involved than as written, but nothing that most adept sailors couldn't handle, if you have the time.
Finally... no sense curing the damage if you haven't eradicated the source. Find out where the water came from and make sure it has been dealt with. Good luck, feel free to contact me if you wish.
P.S. I've yet to find a cored boat of significant age that is totally free of moisture in the deck. This should not scare you at all, it is the norm.

I have just become the owner of a J-24 #266. We bought the boat knowing that we would have to do some repair in spots on the deck and understand that this (water saturation of the balsa core)is something of a common problem.

Please advise as to the procedure and materials to do this.

hanks,
Thomas Pittard