Filling in holes in the hull from old Blakes sea cocks

[hisw]

Hi,

I am after the forums advice as to the best method of filling in the four bolt holes in the hull left by the blakes sea cock that I am replacing with a threaded skin fitting.

The hull is 1.5-2cm thick solid glass

Thanks

 

[Stemar]

I'd be inclined to drill out the holes a little oversize to ensure they're good and clean, then fill with epoxy and thickened with whatever comes to hand. I'd favour microbaloons as they're easier to sand if necessary and you don't need huge structural strength.

You want it thin enough to get down into the holes to fill them right up and thick enough to stay there.

 

[Poignard]

I would also countersink the holes at each end.

 

[Tranona]

Clean each hole and fill with a wooden plug soaked in Epoxy. Leave a countersink at either end then fill with epoxy filler. Belt and braces laminate a layer of glass cloth on the inside.

 

[Scotty_Tradewind]

I would also countersink the holes at each end.

beat me to it.... this makes sure the 'plu' fits tight and doesn't fall out one way or the other.
Epoxy added with thickeners is best to use when filling old GRP. This 'opens' up the epoxy making it 'stronger'/less brittle.
Like a potter adding grog to clay etc..

 

[yoda]

Sorry but for me the only way to do this is with a proper glass repair over the entire area of the 4 holes with 3 or 4 layers of glass and then re-drill for the new skin fitting. I know epoxy is good but will a straight sided plug take the potential forces that may be experienced coming off a heavy wave? Done right - done once.

Yoda

 

[Tranona]

Sorry but for me the only way to do this is with a proper glass repair over the entire area of the 4 holes with 3 or 4 layers of glass and then re-drill for the new skin fitting. I know epoxy is good but will a straight sided plug take the potential forces that may be experienced coming off a heavy wave? Done right - done once.

Yoda

In my experience, yes. Have done it a couple of times and never any problem.

 

[Porthandbuoy]

Did the same job a few weeks ago for a redundant seacock and through-hull echo sounder transducer..

Bolt holes drilled slightly oversize to expose clean glass. Used a countersink to give them a 'rivet' profile inside and out. Filled with microfibre thickened epoxy.
Did a similar job on the larger hole where the spigot went through. I was happy to do this as hole diameter is/was less than laminate thickness.
Painted the outside with epoxy resin.
When hard I ground the inside to expose clean laminate and glassed the whole lot over with carbon fibre (I had some lying around).
I don't think it will fall out.

I don't agree with using a wooden plug. If it gets wet it could swell and start splitting your laminate/repair. West recommend making a thickened epoxy plug, sticking that in place, then fill from either side.

 

[RMC]

I have also done the same job on my boat - But between tides! I used epoxy to fill the old holes and found that the outer flange face on the new skin fitting covered the old holes, thus reducing the chance of movement of the epoxy.