GRP Edge Repair

[JAW911]

I need some help please on the best way to repair the piece missing out of the starboard upper edge on this grp dinghy. I appreciate it will be strengthened when the inner and outer gunwhales are fitted but I want to repair the missing piece without the repair showing internally or externally. Will that be possible do you think and if so how best to achieve that (or am I overthinking here!!) ?

 

[Hacker]

If you grind out bevels on both sides you will be able to lay up some new glass. You will ideally need to find a curved surface to layup against, you could take a flash mould to obtain the correct curve.. It is likely that the repair area will be larger than any inwhale and out whale, so it will show and you will need to paint the whole boat if you don’t want it to be visible.

 

[JAW911]

Yes I could make a reverse mould from the opposite side, thank you. I was going to paint inside and out anyway so that should be fine. I had visions of needing to layup a much thicker area but I expect I should be able to work to roughly the same thickness as is. I’d quite like to have the external gel coat ‘shiny’ so I was intending spraying or rolling/flatting gel coat sufficient for cutting back and polishing. The boat came with a can of East Coast polyester gel coat which I expect is the same colour but need to check.

 

[Boathook]

Yes I could make a reverse mould from the opposite side, thank you. I was going to paint inside and out anyway so that should be fine. I had visions of needing to layup a much thicker area but I expect I should be able to work to roughly the same thickness as is. I’d quite like to have the external gel coat ‘shiny’ so I was intending spraying or rolling/flatting gel coat sufficient for cutting back and polishing. The boat came with a can of East Coast polyester gel coat which I expect is the same colour but need to check.

If you make it all shiny every defect will show up, possibly including the repair. A lot of gel coats are clear and require pigments to be added.

 

[Hacker]

If you have gel coat then remember you either need to add wax or lay it up against a barrier so that it hardens properly.

 

[William_H]

I would suggest a repair similar to filling a hole in a hull of similar size. Start as said by chamfering the edges like out 1cm on both sides. Clamp something like a batten on inside that will support a plastic bag of sand to get an inside support near to level with half way through the hole. Tip the dinghy up on it's side so you can work on horizontal surface to lay up layers of cloth in the hole and progressively larger to sit in the chamfer. Lay it up to level or above hull.
When this layup is firm enough to support the laying up of a matching patch from inside. Tip dinghy on it's other side. Timing here is critical as you want the first patch strong enough but still chemically active to bond with the next patch.
When the repair is hard you can grind it down to size and hopefully level. (some days)
You can use polyester resin or better epoxy. Use glass cloth or better carbon fibre cloth. Just make sure the job is done in a warm place. ol'will

 

[Refueler]

Chamfer the inside and outside edges so that when you add matt / resin and then finishing filler - the whole locks itself to the original ...

Sand back to the profile as best you can ...

Then I suggest a capping rubber fender ... its U shaped and you just press it down over the GRP edge and it grips .. similar to this ...