Hull Core Repairs, Post Blister Repairs

[CJV]

Hello,
My Tartan Ten (hull #282, 1981) had a blister problem repaired before I bought her in May of 2004. She also had a core delam problem which I am now repairing. After removing the inner skin and affected core, some of the putty-filled blister repair holes on the now-exposed inside surface of the outer skin are visible. They show up as perfect white circles about 1/8" in diameter. In two cases they are missing altogether so you can see clear thru the hull.
I''m wondering what''s the best way to proceed when re-coring:
1. Glass over all affected areas with epoxy & glass fabric, essentially thickening the skin but ensuring no further mechanical separation of the putty.
2. Ignore it and lay new core above those areas.
3. Grind and fair from the outside the areas with blister repairs.
4. Grind from the inside and fill/fair with putty, then glass another surface in before applying core material.

As far as I can see, #1 would make most sense. Am I over-engineering this fix?

[LH44]

I have just completed replacing approx 10 sq foot of balsa core in the bottom of a J36. I did the repair from the outside and started by removing the outer laminate and the rotted balsa core. The interior laminate showed holes from cabinetry screws, etc.

I did the repair as follows:
1. Wetted out the interior laminate and new balsa core with neat west system epoxy.
2. Prepared a mixture of resin and collodial silica to a thick consistency and then coated the interior laminate.
3. Allowed the squares of balsa core to open up over the edge of a table, and filled all of the joint lines (in both directions) with the thickened mixture.
4. Pressed the balsa core in place and was presently surprised in that it did not need any support even though it was a vertical surface.
5. Then proceeded to glass a new exterior laminate to the exterior of the balsa core.

By adding glass over the interior of your exterior laminate, i do not think your cores will line up properly and you run the risk of creating a hard spot. The thickened epoxy mixture will more than provide "insurance" against your exterior work as well as assure a good bond with the balsa core.

[sailingfool]

Best of luck with whatever way you go, but I gotta say that these posts provide an opportunity to harken back to numerous previous threads about the risks of cored construction in hulls. I''ve become a firm believer in all glass, and the idea of personnally patching a hull that will then take my family many miles from shore is quite a leap of faith.

Good luck.