Filling holes

[Dazedkipper]

What's the best method to fill redundant through deck bolt holes, thinking something strong because I'll be re-drilling close by to fit new hardware?

 

[sarabande]

what is the deck material ? Ply, steel, sandwich, balsa, GRP, plain timber ...

 

[laika]

My amateur method: Grind down the edges with a dremmel so there's a bit of a slope on the edge for the first cm or so. stick a bit of tape firmly under the hole. Mix up some epoxy and thicken with colloidal silica. Fill all but the last cm or so. When cured cover with gelcoat+wax in styrene or gelcoat filler to a bit above level with the deck. Wait to cure. Rub down through the grades.

Conventional wisdom says that gelcoat won't really bond to the epoxy except mechanically. You could probably improve your chances by roughing up the top of the epoxy but I've never had any come off and if it does so what? Just re-do it.

(Edit: Of course I should have asked sarabande's question first

 

[Dazedkipper]

what is the deck material ? Ply, steel, sandwich, balsa, GRP, plain timber ...

Sorry, yes of course it's rather important. Balsa cored GRP with light layup internally plus flow coat, overall thickness approx 30 mm.

 

[oldsaltoz]

What's the best method to fill redundant through deck bolt holes, thinking something strong because I'll be re-drilling close by to fit new hardware?

In your case (with a core filled deck).

Re drill the hole a few mm wider to get a clean edge, then put a bent nail into a drill and remove the core material between the deck and inner skin.

Check that the area is bone dry. Important because you do not want to trap any moisture.

Mix a small amount of epoxy resin and hardener and apply this to the internal area covering all surfaces.

Now mix another small batch or resin and hardener and add some Micro-fibres to the mix about the thickness of toothpaste.
Tape up the bottom hole and put a prop under it to stop it bulging.

Tape off the area around the hole on deck to speed up cleaning later.

Apply the mix starting by pushing it to the outer edges onf the void, try to eliminate any air bubbles by working your way around the hole in one direction.

Finaly fill the small void in the middle, leaving the top leval a couple of mm below the deck level so you fill this with a suitable filler or gel-coat after it's cured (24 hours).

Good luck and fair winds.

 

[William_H]

I would be inclined to use polyester resin for the whole hole fill. Bonding should not be an issue if as Oldsaltoz suggests you scrape out some of the softer core amterial. You can put pigent into the whole mix to get the desired colour. good luck olewill

 

[oldsaltoz]

I would be inclined to use polyester resin for the whole hole fill. Bonding should not be an issue if as Oldsaltoz suggests you scrape out some of the softer core amterial. You can put pigent into the whole mix to get the desired colour. good luck olewill

Not best practice, an epoxy should be used as the bond will be both mechanical and chemical. This is not the case with standard resins, and with core to protect I would never recommend this.

Good luck anf fair winds.

 

[oldsaltoz]

Tip:

If you plan to gel-coat this repair, save the surface material you remove with the drilling and any sanding, mix this in with with the new gel coat.

The result will be an easier colour match and best of all the older material will continue to fade at the same rate as the original gel coat, or at least look better longer.

Good luck and fair winds.

 

[ghostlymoron]

I filled some big bolt holes with some gap repair paste in a tube left over from another job. Its blue and has fine glass fibres in it. Sets very hard. When set, I ground of a couple of mms and filled with coat filler. Seems pretty solid.