prv
Well-Known Member
I've done a fair bit of GRP work on Kindred Spirit and Ariam over the last few years, so I'm quite comfortable with the basics. However, I have a challenging job coming up and I thought I'd see if there's a cunning wheeze I'm not aware of.
The previous owner had some largeish cockpit speakers installed - maybe 8" diameter. Unfortunately they were put in the inside of the coamings, effectively the "seat backs" for the cockpit benches, and quite vulnerable to damage. The ones in place when we bought the boat were comprehensively smashed, I replaced them (trying to pick a low-profile type without easily-damaged design features), and after a season and a half taking reasonable care both were broken again. I think the only solution is to remove them and glass up the holes. I'll then experiment with transducer-type speakers mounted on the back, but since we rarely use the stereo anyway, even if those don't work it will still have been worth removing the old ones.
So, I need to fill two large holes in a flat expanse of GRP, with no useful access to the back (I can get a couple of fingers to it, but that's all), in a position that will be highly visible most of the time we're using the boat. The basic mechanics of filling the hole hold no fears, but I suspect it's going to be bloody difficult to get a good finish on the gelcoat.
My plan is to do the structural filling first, let that cure to give a solid base to build from, and then try to fill the remaining depression. I guess I can either try to mould a flat surface directly with gelcoat and a smooth sheet, or daub on flowcoat deliberately overthickness and then sand back to level. If I had access from the back I'd definitely be going the smooth sheet route, pressing a sheet of slightly flexible plastic over the surface and then painting gel onto it from the inside. But I can't do that. So the nearest maybe would be to pre-paint the sheet (and apply plenty to the depression as well) and then press it down into place. Trying to press a sheet onto wet gel has never worked well for me, always leaving bubbles, hence the thought of painting a layer on first, which I haven't tried before. The appeal of course is that it gives a shiny finished surface more or less immediately. But I have my doubts about it working. So fill and sand it is, I guess, but that generates a lot of dust, tends (at least when I do it) to end up wavy rather than flat, and it's hard to get back to a smooth shiny finish. I thought I was done with that when I refinished the binnacle last year
Thoughts?
Pete
The previous owner had some largeish cockpit speakers installed - maybe 8" diameter. Unfortunately they were put in the inside of the coamings, effectively the "seat backs" for the cockpit benches, and quite vulnerable to damage. The ones in place when we bought the boat were comprehensively smashed, I replaced them (trying to pick a low-profile type without easily-damaged design features), and after a season and a half taking reasonable care both were broken again. I think the only solution is to remove them and glass up the holes. I'll then experiment with transducer-type speakers mounted on the back, but since we rarely use the stereo anyway, even if those don't work it will still have been worth removing the old ones.
So, I need to fill two large holes in a flat expanse of GRP, with no useful access to the back (I can get a couple of fingers to it, but that's all), in a position that will be highly visible most of the time we're using the boat. The basic mechanics of filling the hole hold no fears, but I suspect it's going to be bloody difficult to get a good finish on the gelcoat.
My plan is to do the structural filling first, let that cure to give a solid base to build from, and then try to fill the remaining depression. I guess I can either try to mould a flat surface directly with gelcoat and a smooth sheet, or daub on flowcoat deliberately overthickness and then sand back to level. If I had access from the back I'd definitely be going the smooth sheet route, pressing a sheet of slightly flexible plastic over the surface and then painting gel onto it from the inside. But I can't do that. So the nearest maybe would be to pre-paint the sheet (and apply plenty to the depression as well) and then press it down into place. Trying to press a sheet onto wet gel has never worked well for me, always leaving bubbles, hence the thought of painting a layer on first, which I haven't tried before. The appeal of course is that it gives a shiny finished surface more or less immediately. But I have my doubts about it working. So fill and sand it is, I guess, but that generates a lot of dust, tends (at least when I do it) to end up wavy rather than flat, and it's hard to get back to a smooth shiny finish. I thought I was done with that when I refinished the binnacle last year
Thoughts?
Pete
