sealing holes

[sauerleigh]

I spent a good part of the day sealing up about 90% of the various holes in my deck. Terrance, (hp18carr) had asked about this on another post so here goes.
The boat has to be dry. Moisture and epoxy don't get along too well, polyester might not be quite so bad. With a plywood core, if the hole is already oversize, use a rat tail file to clean out any loose debris, especially old silicone. If you can get away with a larger hole, go up to the next size by 1/32". Tape the bottom of the hole with vinyl weather type tape. Set aside a portion of your epoxy mix and ad a filler, put it in the frig, with the remainder of the epoxy, paint the inside surface of the hole, let it soak in and paint it again. After you have painted a number of hole you can start to add the thickened epoxy mix. The plywood will absorb the plain epoxy better and give the thicker stuff better bond. I found that if you use the thickened epoxy right off the bat that there is considerable shrinkage when the mix goes off, this particularly true with polyester resin.
When filling holes in the phenolic honeycomb cored areas of the cabin top, I fill the hole first with plain epoxy. I have had a number of holes that have swallowed large quantities of epoxy, far more than three or four segments of the honeycomb that it would take to fill something like a 1/4" dia hole. Hopefully the epoxy will fill some of voids in the honeycomb that were dissolved over time. In a few days, I'll drill them all out with a 1/16" larger drill and fill them again with thickened epoxy.
Silicone sealer does not penetrate wood very well if at all. Add to that, most fasteners used have a thread running up to the head, a nice path for water.
Fiberglass boat, with lots of wood inside, and most of that wood is structural. Keep it dry and it will last longer.

[hp18carr]

Brian

Thanks for taking the time to spell it out for me... I'm sure others will appreciate it as well. Sorry for burying the question under another post.

Terrence
Wilmington N.C.
Chrysler 26 1980
Pandora (for now)

[shunt1]

While repairing my mast step, I discovered the phenolic honeycomb cored areas of the cabin top that you mentioned. Some rather large sections of the honeycomb were not filled with resin and were hollow. As I was sanding the fiberglass to get a 12 to 1 slope, these hollow sections of the honeycomb would shatter. Seriously, in large areas, there was nothing but hollow paper honeycomp.

This is probably why my mast step broke off in the first place, since that section of the cabin top was rather weak.

Rather than cause even more damage, I decided to fill each of those paper honeycomb cells with thickened resin and let it cure for a few days. A rather slow process, since I did not want any air bubbles in the cells. Once cured, I was then able to sand the fiberglass down to a proper 12 to 1 slope.

[Alanhod]

Really good thread Sauerleigh.

Thanks
Alan