Fiberglass and Paint Repair
G'day all,
Just wondering if anyone can give any advice on applying flowcoat please.
I hit the trailer when retrieving the boat just before Christmas and gave a real deep scratch to the gelcoat and also dug out a little fiberglass I believe, so over the last week and a bit I've scrapped out the scratch to fill it, and have also laid a little bit of new fiberglass where I gouged some out.
Anyway I sanded the area back laid up the glass and when I was ready to do the gelcaot I went to get it at Whitworths, and the guy serving me there tells me I shouldn't use gelcoat for the job, he recommended I use flowcoat. He explained that gelcoat dries tacky and it is more used for making molds, and that flowcoat is for a finish over fiberglass.
So I take his advice and buy the flowcoat, now I have taped up the area with double thickness masking tape (put 2 strips for every side of the outside area that I didn't want to get the new flowcoat over) and applied a thick-ish layer of flowcoat with a paint brush.... All good the flowcoat has gone off and I have left it 24 hours before sanding it, but the problem I am getting is I do the first bit of sanding with a higher grit snadpaper say a 240 or 120 grit and lightly knock of the rough brush strokes from the brush, I then come down to a 400 grit wet and dry, down to a 600 grit wet and dry, and lastly a 1200 grit wet and dry, and the main problem is before I've even hit it with the 1200 grit I can see the outside area of the repair has the fiberglass showing through, and the area I am working on is basically showing through also, its like not sanding too heavy handed, and using a low grit sandpaper, but I'm wearing away the gelcoat of the outside area and then also the repair area.
I've watched a heap of videos on repairs to fiberglass damage, minor and major, and one thing I have noticed with most (american) is they use gelcoat, not flowcoat and their work doesn't seem to have the repair work show through, or they rub too much gelcoat off from the outside area of the repair.
Am I possibly not putting enough flowcoat on? from what I have watched I believe I am applying the same amount as the guys in the videos, or should I overlap the repair area heaps more and try and blend it in? Or should I spray it on instead of painting it on, or should I use gelcoat?
Really stuck on this one and so wanna get my boat out on the water again, any advice very much appreciated.
Thanks
Geoff
eziliving
Posts: 873
Date Joined: 30/12/09
You can use gelcoat as that
You can use gelcoat as that is what I would use but you just have to add wax and styrene to it to get the smooth finish. With your fibreglass repair did you sand it back prior to applying the flow coat? How did you apply the flowcoat? Did you spray it of brush it cause when you brush it you generally apply it pretty thick did you use a sanding block to sand it cause what tends to happen if you don’t use a sanding block is exactly what your problem has become
What I would do to fix this is get a sanding block and rub it back so it’s all flat just like it was before the damage then lightly sand past where you have rubbed through. Then tape it off past the rub through and where you have sanded. Then get some gelcoat and add some wax and styrene to it then spray the gelcoat on. Then use a sanding block and start sanding it back lightly over the repair. You will see a distinctive edge where the gelcoat isn’t sticking smooth area as it hasn’t been sanded as as you sand the edges it will just flake off until you hit the sanded area. Then once you’ve got the edges sorted lightly rub the whole area to remove any blemishes. The cut and polish and all should be good.
There might be other ways as I’ve been out of the game for over 20 years but it should work. Good luck
Get busy living, or get busy dying!
z00m
Posts: 1086
Date Joined: 10/05/14
Gelcoat vs Flowcoat
Gelcoat and Flowcoat are the same product. Flowcoat just has the styrene and wax already added.
If the repair area is smaller than an a4 sheet then you can easily apply gelcoat but you need to cover the surface with plastic so it can cure in the absence of oxygen which will make it tack free. Otherwise just apply the flowcoat.
Apply as much flowcoat as you can without it dripping/falling off. Make it as thick as possible so you have enough to run your sanding regime. If you have sanded through the gelcoat adjacent to your repair then you know you have sanded too much and your repair wasn't tall enough to cope with the sanding amount. Keep the surrounding area taped off until you are ready to do your last sanding to protect it.