Hello,
A few weeks ago I glassed the outside of my Prospector. This is my first build. I thought at the time it went well despite my nervousness of this process. However there are some flaws.
1. There are a few "stripes" showing where you can see where I epoxied in sections. I thought I brushed from wet to dry, but maybe not. I do recall noting how when I was about to start on the next section the leading edge appeared "drier". I know there is nothing I can do about this now, but can anyone explain how I can avoid this next time? Fortuneatly, they are generally only visible when viewing at certain angles. You can see an example here just past the end of the stem
http://s1193.photobucket.com/albums/aa3 ... 000186.jpg
2. I did 4 coats, but the last 2 were rolled on and brushed out. There are at least a couple of areas where the epoxy is too thin. I suspect 1 of these I missed on the very important second fill coat, since there is a ridge around it, and I can feel the weave of the glass. The other area just did not get enough. I think rolling the 3rd coat was a mistake. Other posts recommend a foam brush. My plan is to sand the hull (carefully on the thin areas), apply an initial coat to the thin areas. Perhaps by first letting the new epoxy gell a bit before applying. Then do a final coat to the entire hull with a foam brush this time.
Does that sound reasonable?
Recommendations on what sandpaper type and grit to use to prepare it for more epoxy?
Thanks,
Dave
fixing epoxy mistakes.
fixing epoxy mistakes.
Last edited by DaveA on Sat Oct 16, 2010 6:45 am, edited 2 times in total.
What resin and hardener did you use.
In my limited experience, I think I would wash the heck out of it with green scotch brite pads and water to remove any blush, dry well, and put on another coat or two or three of build epoxy before I sanded. Sanding bare cloth I think is going to make things worse.
I used non foam hotdog rollers with a short nap. I also mixed 9 oz total at a time and used strong paper plates as a tray to roll from. I used a medium hardener and thin resin.
I think if you build up the epoxy you will be able to sand out the bumps and ridges without getting down to the glass, and it will float nicely.
Looks good though. The biggest issue I see is that your garage is too clean.
I like the saying "Perfection is a goal not a destination."
Matthew
In my limited experience, I think I would wash the heck out of it with green scotch brite pads and water to remove any blush, dry well, and put on another coat or two or three of build epoxy before I sanded. Sanding bare cloth I think is going to make things worse.
I used non foam hotdog rollers with a short nap. I also mixed 9 oz total at a time and used strong paper plates as a tray to roll from. I used a medium hardener and thin resin.
I think if you build up the epoxy you will be able to sand out the bumps and ridges without getting down to the glass, and it will float nicely.
Looks good though. The biggest issue I see is that your garage is too clean.
I like the saying "Perfection is a goal not a destination."
Matthew
I'm sorry I missed the few weeks ago part.
From the West web site. "Epoxy surfaces that have not fully cured may be bonded to or coated with epoxy without washing or sanding. amine blush may appear as a wax-like film on cured epoxy surfaces. It is a by-product of the curing process and may be more noticeable in cool, moist conditions. Amine blush can clog sandpaper and inhibit subsequent bonding, but this inert substance can easily be removed.
To remove the blush, wash the surface with clean water (not solvent) and an abrasive pad, such as Scotch-brite(TM) 7447 General Purpose Hand Pads. Dry the surface with paper towels to remove the dissolved blush before it dries on the surface. Sand any remaining glossy areas with 80-grit sandpaper. Wet-sanding will also remove the amine blush."
I think that no matter which epoxy I was using I would wash first. Even a thin film of blush can cause bond failure. For any ridges I would use a cabinet scraper to try to take off the high spots.
Matthew
From the West web site. "Epoxy surfaces that have not fully cured may be bonded to or coated with epoxy without washing or sanding. amine blush may appear as a wax-like film on cured epoxy surfaces. It is a by-product of the curing process and may be more noticeable in cool, moist conditions. Amine blush can clog sandpaper and inhibit subsequent bonding, but this inert substance can easily be removed.
To remove the blush, wash the surface with clean water (not solvent) and an abrasive pad, such as Scotch-brite(TM) 7447 General Purpose Hand Pads. Dry the surface with paper towels to remove the dissolved blush before it dries on the surface. Sand any remaining glossy areas with 80-grit sandpaper. Wet-sanding will also remove the amine blush."
I think that no matter which epoxy I was using I would wash first. Even a thin film of blush can cause bond failure. For any ridges I would use a cabinet scraper to try to take off the high spots.
Matthew
I have the same stripes on my Nomad, visible if you know where to look. I suspect they are to do with my poor squeegee techniques, but not 100% sure. Also very interested into any insights why this happened and how to prevent this from happening next time.
BTW Dave I snuck a peek a few weeks back and it looks awesome!
Mike
BTW Dave I snuck a peek a few weeks back and it looks awesome!
Mike