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Long story short, I have some bad feathering in the glass on top of my kaholo. Should I sand after my first coat of epoxy dries? My thinking is I get the random bits of glass out wiht this sanding. I'm afraid if I go over with 2nd coat before sanding, it will make it tougher to hid this overlap/feathering issue.
Any advice is appreciated.
3 replies:
RE: sanding 1st layer of epoxy
two thoughts come to mind.
one is to add a scraper to your arsenal (clc sells them). they are very good for feathering and avoid generating a lot of dust.
another is that when feathering, you are trying to fair out areas of different hights. it can be really challenging to do this efficiently if you can't fill the edge between the two different hights with epoxy to allow you to get a smooth feather. when i have feathering to do, i will take a swipe of epoxy applied with a squeegee to fill/fair that edge and then scrape or sand it. this way when i am done, less likely for me to need to add epoxy to fill a void. in addition, it allows me to add epoxy where it is needed vs all over the place where i am only going to sand it off.
regards,
howard
RE: sanding 1st layer of epoxy
Ben, does your "overlap/feathering issue" involve an overlapping splice between two equal thicknesses of glass, because one piece of glass was not large enough to cover the whole area? I have always just scraped and sanded those seams down so that they are the same height and thickness as the glass on both sides. I might describe that more as leveling than feathering.
If the two adjoining surfaces are not equal in height, then we're getting into what I think howard is talking about. In that case, it really does help to add some kind of material to fill the gap between the heights. A fairing compound such as epoxy thickened with microballoons is often used when the result will be painted. If a bright finish is wanted, the extra unthickened epoxy that howard mentioned is a good way to go.
Old Yeller
RE: sanding 1st layer of epoxy
» Submitted by Old Yeller - Sat, 7/27/13 » 11:04 PM
If you have the time to let epoxy cure enough to sand it, I think that would be fine. The 2nd coat will not have a chemical bond with the first coat, but it is only a fill coat to smooth out the surface, so I don't see that as an issue. I have done the same thing myself, and have been happy with the results.
I like to aim for chemical bonds where the structural integrity of the hull is a stake, but do think that secondary mechanical bonds are generally strong enough for the boats that we build.
Old Yeller