Isopod p40

[PabloPicasso]

Is isopon p40 a good sun stance for below the waterline GRP hull repair? Just filling dings scrapes in the gelcoat rather than major repairs

 

[Tranona]

No. You need underwater filler or epoxy. Plastic Padding do underwater in tubes for small jobs, but if you are doing a lot then probably worth using something like International Watertite or mixing your own using epoxy and a fairing filler.

 

[G12]

If it's just dings and scrapes in the gelcoat then you'd be better off filling it with gelcoat or an epoxy filler which will have far superior adhesion than the Isopon which will be based on a cheap polyester resin. If you really need it to be fast and dirty then the Isopon will be the cheapest.

 

[Ardenfour]

...but probably P38, polyester filler, rather than P40 which has glass strands sticking out all over the place

 

[PabloPicasso]

Yes p38 looks better. But two part epoxy with a filler, or just gel coat would be the correct stuff to use, no point making a mess of it!

 

[TQA]

P 38 Noooooooooooooooooooooooooooooooooooooooo Not suitable for underwater use. It WILL blister.

You are not going to need a lot so the extra expense of epoxy will not break the bank. Use silica as the thickening agent. B***er to sand though so get it as fair as you can when you apply it. http://www.westsystem.com/ss/repairing-individual-and-early-stage-gelcoat-blisters/

 

[PCUK]

P40 is fine underwater as it is basically just polyester resin and matting pre mixed.

 

[alahol2]

White superfine Milliput does me for covering over screw heads in gelcoat and for minor dinks. It doesn't quite match the gelcoat but then neither does the gel filler. It lasts indefinitely on the boat and is very easy to use in small quantities. A definite place in the 'repair materials' drawer.