microballoons below the waterline

[SailMaui]

Aloha, I recently had some fiberglass work done to reinforce the keel on my 23 MK1. The guy who did it used microballoons for faring. After he did so I read in Don Casey's book that you should never use microballoons below the waterline because they absorb moisture. I don't know what to do because sanding all the balloons off will damage the fiberglass job and then I'll have to redo it. The boat is stripped down to factory pigment so I will be barrier coating the bottom with 2-3 coats, or more if I can get more out of a gallon. I'm hoping someone will tell me that the barrier coating will prevent the balloons form absorbing water.
So my optioins as I see it are:
1) sand away all the microballoons, if damage to fiberglass(Nitex) occurs I can laminate over it with some 10 oz then fair with Qcel.
2)leave it and the barrier coating will seal in the balloons preventing them from absorbing water.
3)fare over the balloons with Qcel then barrier coat and paint.

Any opinions would be great. Also this person did a poor job faring the deck and with balloons and all I have left is Qcel, how hard is it to sand down Qcel? Is it worth going and buying more balloons?

Mahalo,
Matt and Stacey

 

[Loren Beach]

I have used "microballons" for a lot of fairing above the water (not what you asked...), and can only speculate that being surrounded in epoxy they should be very much sealed from any moisture. After all, epoxy has been used for almost 30 years to seal up the bottom of boats to prevent (or at least drastically slow?) water from entering the laminate on older boats.

About the only filler that I know for sure is bad for any underwater use is clay -- and that's reportedly the filler in Bondo (r). I have seen that stuff later fall off of old keel repairs and fairing efforts.

Mind you, I'm not saying Mr Casey is 100% wrong, but it may be a situation where the problem is only 5% likely to occur rather than 95% likely.


There is a prior thread on this site with a lot of pics of a 23 mk 1 that had a huge bottom restoration done. Might take some searching to find it...
Anyone else with a link, chime in!


Best of luck,
Loren

 

[Emerald]

By micro-ballons, do you mean West System 410? If so, I wouldn't worry about it at all. As Loren says, properly done, this will be epoxy saturated. I have used 410 below the water line, under Interlux Interprotect 2000E, and have not had any issues, and never encountered any information on West System's website indicating not to use the 410 for final faring, as something like 406 is much harder and does not fair as well as easily. Also, if you apply the barrier coat properly, you should really be fine on having a sealed bottom. Don't skimp on the coating. Buy the extra material if you need it to get the required buildup. The cost of doing it the right way up front is much less than redoing it later


A link to West 410:

http://www.westsystem.com/ss/410-microlight/

 

[Bob Hunt]

The album "Makana repair" shows a repair that was completed last month of a catamaran keel that was damaged after a collision with a submerged cyprus stump. Absolutely no resin putty was used to fair the exterior surface. All of the fairing was carried out by molding with 1.5-oz. chopped-strand mat followed by sanding to fair. Except for a few surfboard dings, this repair was done by a young man who had never repaired fiberglass before.

Link to Makana repair album: http://www.ericsonyachts.org/infoexchange/album.php?albumid=169

Bob Hunt

 

[Bob Brigham]

I agree with Loren...have used micros for many projects and they do get resign-saturated...you should not have to worry if the job was done properly