Cutting a bevel in GRP

[PaulRainbow]

I bought a small angle grinder,

one that could be held and used in one hand, for such a job. I considered trying to make some sort of conical backing pad but in the end just used the ordinary flexible backing pads and a coarse sanding disc ( the grinding disc was far too aggressive) and did the "repair" from the outside anyway, although I started with a layer of biaxial glass cloth on the inside laid up against peel ply supported by a flexible pad taped to the outside

That's exactly what i used for the tapers, although i did put a small taper on the inside as my hole was two inch dia'. Rather than peel ply i cut a piece out of a 4 pint milk "bottle" and stuck it to the hull with tank tape.

 

[C08]

U
I'be been thinking of buying one of those. Which make did you buy?

I bought a cheapo Silverline PowerFile about £28 delivered. I used it for days on end fitting a bow thruster and apart from the belt slipping off a few times when I abused it it performed well without any problems. and it felt a lot safer than an angle grinder as the belt speed is quite modest and it seems difficult to imagine haviing an accident with one. Wish I had one years ago.

 

[Poignard]

I bought a cheapo Silverline PowerFile about £28 delivered. I used it for days on end fitting a bow thruster and apart from the belt slipping off a few times when I abused it it performed well without any problems. and it felt a lot safer than an angle grinder as the belt speed is quite modest and it seems difficult to imagine haviing an accident with one. Wish I had one years ago.

Thanks :encouragement:

 

[Yngmar]

The local GRP expert, who's always worth watching (for I have learnt many things from watching how he does his job) used an angle grinder, with what looked like a sanding disc. This made short work of it - a sander would probably be a bit slow for it. He's done a fine job repairing a friends encapsulated lead keel after they've hit a submerged piece of Ireland. The bevel area is indeed enourmous compared to the size of the hole, and loads of glass and resin went into it.

 

[lw395]

The local GRP expert, who's always worth watching (for I have learnt many things from watching how he does his job) used an angle grinder, with what looked like a sanding disc. This made short work of it - a sander would probably be a bit slow for it. He's done a fine job repairing a friends encapsulated lead keel after they've hit a submerged piece of Ireland. The bevel area is indeed enourmous compared to the size of the hole, and loads of glass and resin went into it.

Repairing grounding damage is a different game to filling a neatly bored hole.
Impact damage will have stressed the grp over a wide area. Often with hidden cracks and broken fibres well beyond the visible damage.
So it's normal practice to remove a lot of material.