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blueman blueman is offline
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Default Sanding/buffing/polishing epoxy clear coat top

"Mike Marlow" writes:
blueman wrote:

So specifically,
- Can the gloss be restored by sufficiently fine sandpaper grits (I
have up to 3000) and/or by buffing?


Yes, but there is no need to go beyond 1000 grit before switching over to
compounds. Wet sand it to keep grit from building up in the paper. Use a
foam block to keep an even pressure and avoid gouges from finger pressure.


- Will (hand) sanding alone be sufficient by using sufficiently high
grits or do I need to use an orbital buffer/polisher?


Hand sanding is just fine. Orbitals are fine as well. I've we sanded more
cars than I can count, by hand.


- If buffing/polishing is necessary, how would you go about it? (what
types of pads and/or polishes and buffing compounds)


Knock the dust nibs down with 1000 grit wet. Get the surface as smooth as
you want it and switch over to any rubbing compound you like. Automotive
rubbing compounds should work just fine. Use a medium cut rubbing compound
and if you want, go over that with a swirl mark remover. Use a soft cloth
and some elbow grease with the rubbing compound and less elbow grease with
the swirl mark remover. You can of course, use a buffer as well, but be
careful - it's easy to burn through even tough finishes with a buffer.


Thanks to all for the helpful advice.

I ended up doing the following:

1. Applied about 6 coats of West System 105 Resin with 207 Clear coat
hardener using a dense foam roller. However as mentioned above, the
roller itself seems to have deposited random fine nibs. I estimate
that the total final thickness was about 30-40 mils. Finish was
applied to all sides including the top, bottom, and sink cutout area.

2. Started sanding at 220 which was enough to knock down the specks and
smooth out imperfections

3. Wet sanded up to 3000 in increments as follows:
220-320-400-600-800-1200-1500-2000-2500-3000
Probably way overkill but I had the sandpaper from my "Scary Sharp"
method of sharpening steel

Note at this point the top was perfectly smooth but the finish was still
quite dull (though uniformly so without any visible sanding marks)

4. Switched to a power buffer with a wool bonnet (bought for about $25
at Harbor Freight)
At first I tried various colored buffing compound sticks but they did
absolutely nothing (probably because very little compound seemed to
transfer to the bonnet from these hard sticks -- perhaps I was doing
something wrong...)

So I switched to Automotive rubbing & polishing compound (given that
I had already sanded up to 3000 grit, I found that I could start
with the polishing compound and skip the rubbing compound). The
compounds come as loose pastes that I applied quite liberally to the
vanity surface before buffing.

I ended up buffing at the highest speed (~3000 rpm) after gradually
ramping up and testing for damage. Note that the buffer never seemed
to damage or dig into the coating too much even with some pressure
and even with extensive buffing - probably due to the hardness of the
epoxy. So, while I was careful, the epoxy coating seemed to be pretty
power buffer friendly. Of course, I kept the buffer moving to avoid
swirl marks.

I continued to buff for a while, occassionally adding water to the
top to keep it damp and to help wash away the polishing compound.

5. Finally, I cleaned the top with water and a soft rag.

After this the top was BEAUTIFUL and clear like glass -- in fact, if
anything the biggest compliment (and maybe criticism) is that it looks
like glass and not like the wood people are used to from projects.

However, I think it is still less shiny and sparkling than the
absolutely crystal clear reflective finish from the original epoxy
topcoat. But since the entire top has been polished uniformly, one
doesn't notice that. And it probably looks richer to not have a
mirror-like reflecting surface that catches all the glare.