GRP Repairs

Last Friday 7th October I borrowed a generator and set to work to grind out the GRP around the cracked areas of the skeg and the redundant openings in the hull. The area around the two hull openings, original heads discharge valve and the old paddle wheel log, were ground back at 1 in 12 to provide a good base for the new GRP. I cut out a simple gauge from ply to check on the angle. Unfortunately I did not take any photographs of this operation as I had left the camera at home. The grinding was carried out with a 41/2" angle grinder that I purchased from Screwfix some time ago it is a variable speed model which I find useful for GRP work as it gives a bit more control of the rate of removal of material. The original plan was to grind back on a taper on the inside as well as the outside of the hull but unfortunately I had a problem getting access to the inside of the hull with the angle grinder so I decided to lay up the GRP on the outside first. I fitted a polythene covered piece of ply over the openings from the inside with a timber wedged against the underside of the deck to hold them in place. I followed the usual procedure for this type of work by cutting out a piece of glass cloth to suit the outer extremity of the prepared area and then cut more of the same shape but gradually reducing in size. I then cleaned up both sides with acetone and gave them a good sanding to provide a key for the new material. Once the outside GRP had been laid up I waited for it to begin to gel before removing the blanks and laying up the GRP on the inside making sure that I had a good bond between the inner and outer layers in the opening and left it to cure. Meanwhile I got on with laying up the new GRP to the defective areas of the skeg again by cutting a series of pieces of glass cloth each reducing in size and laying them in largest first. I would recommend the West Epoxy handbook it is a most useful publication when it comes to this type of work. While working with epoxy I cleaned up the damaged area above the rudder on the starboard side, it looks as though something had become jammed between the hull and the rudder, but it had caused the gel coat to break away  along the edge. This area was repaired using epoxy thickened, to a peanut butter, West Epoxy handbook wording not mine, consistency, with colloidal silica.

Repairs to starboard side of skeg

Repairs to port side of skeg

Infill to redundant heads discharge opening

Infill to redundant log opening

Log opening internal

Heads discharge opening internal

There is a bit of a depression in the GRP on the inside of the log opening this is because the hull is much thicker in this area and to grind out too full depth would entail the work crossing over the centre line to the port side which I was not keen on doing so I worked the layers of glass cloth well in to give a good bond to the outside work.

I have used a number of brushes for this work fortunately there is a Poudland just up the road which is selling everything at 90p you get five brushes endorsed by Tommy Walsh, remember he of Ground Force, they don't like acetone or white spirit much makes the bristles fall out but at that price for GRP work they can't be beaten.

I also found time to fit the new heads discharge seacock so once the hull anode has been fitted  the boat will be watertight from the sea water side there will still be a bit more to do before she can go in though. Next week the plan is to fill and fair the repaired areas where necessary. 

Heads discharge seacock fitted

Work is progressing at a reasonable rate but these jobs always take a lot longer than originally planned fortunately up to now there has been very little in the way of nasty surprises although there is still a way to go yet.