Davis,

You might try making a small hole ate each end of each bubble and using a syringe to inject epoxy and cello-fill int the bubble.  Worked for me.

Cheers,

Dick

   Dick,

Thanks for the suggestion. I may try that technique on some of the bigger spots. My fear is that the majority of the pockets may be too small for the technique you mentioned. Many of the are only about 1/8" to 1/4" in wide. 

   First thing I would do is use a heat gun on the lowest temperature that will soften the resin without burning anything and try to poke the corner of a razor knife through the bubble and press the air out.  If the bubbles are caused by wrinkles on the fiberglass you'll have to cut or grind them out with a dremmel. Or, you can use the heat gun to soften the resin and pull the glass tape out and start over. Be careful with the heat gun and keep it moving. You don't want to hold in one place too long. 

Air pockets are bad because they can potentially allow water into the joint. As the boat flexes, micro cracks will form in the unsupported tape and water from spray, splashes, rain or even just humidity will get under the tape. Then you'll have a reservoir of moisture to be getting through any available channels into the endgrain, resulting in eventual rot.  So I would very much recommend against just leaving it alone.

Depending on just how many and how widely scattered they are, cutting and filling might be your best option. The Jimmy Skiff is a low stress boat. The flat bottom and gentle side curves can be safely held together with less than full strength joints, especially if you run the bottom glass up at least 2" onto the hull. With 6-oz glass, I'd be comfortable with using the epoxy-repaired joints inside.

When I had to repair a joint with a bubble the size you mention, I used Dick's technique, but with unthickened epoxy. I also used a needle on the syringe to get it into the bubble (had a cat that needed nightly injections so was able to get needles legally, don't know how to obtain them without a sick cat).

Lots of bubbles indicate a systemic problem. You might want to post a picture, but my first guess is that your fillets aren't thick/high enough. Removing and redoing the joints would be the best craftsmanship, but before you do that, figure out what the problem is so that you won't just do it again.

Wing's heat gun technique will be a lot less mess than sanding the glass away. You can also avoid sanding away the old fillets by simply laying down a new fillet directly on the old ones. The boat will end up a bit heavier, but the JS isn't a racer, anyway.

Good luck,

Laszlo

 Thanks for all the good information. At this point I have either used a Dremel and razor to cut out most of the air pockets or injected them with epoxy. There are probably a few left, but they are extremely small and scattered. Right now the boat looks hideous. 

My plan is to use thickened epoxy to fill the gaps and create a smooth fillet, add a few coats of unthickend epoxy, and then sand smooth. I am not too worried about strength, because I made the fillets very large and used two overlapping strips of fiberglass tape. I may also add a second layer of tape to the outside of the hull (three layers total) because a gouge there is the most likely way for water to enter the joint. The boat will end up pretty heavy, but that's better than rotting. 

I will also be on the lookout for a sick cat. 

I think the source of this problem was just poor attention to detail. I live about 300 miles from where I am building the boat, and I was trying to do too much in one trip. I applied the glass at about 3 a.m.. I was sick as a dog that day to boot. The fillets were a little sloppy, and I didn't press the glass down hard enough into the fillet or the hull, leaving lots of little floating wrinkles.  I think the mistake will easily double the build time of the boat, make it heavier, and possibly make it more prone to rot. But I have learned my lesson. Don't rush. Even if it takes twice as many trips I will take my time from here on out. 

The good news is the boat will painted, so the aesthetics of this joint aren't quite as important. 

Thanks again for all the input. Also, I am sorry for all the typos. I am fighting autocorrect. 

 I am working on a wood duckling and need some advice. The deck is now joined to the hull and the outside looks better than I had hoped. With a flashlight I see that an inside bow/deck seam has large air pockets that are out of reach for other approaches (cutting out, heating, drilling). Have my hopes up with one suggestion (1/31/16, thanks Laszlo!)--laying down a new fillet on top of the old one. Since this is dissimilar to other suggestions, I wonder if there are more things to consider.  I’d get it as smooth and clean as possible, and lay down a 2nd saturated piece of tape (24”) over the 1st one. Many thanks for ideas, Dave