Part 8: Gloss
Gloss coats are
essentially a second hot coat that is fine sanded, compounded, and polished to
a shine. Typically, gloss coats are found on longboards and retro-style boards,
where weight isn’t a factor. Adding a gloss coat increases the weight of your
board, so typically high-performance shortboards skip a gloss coat and are
considered done after fine sanding the hot coat to 400 grit or so.
If you are making a
longboard, tinted board, or opaque pigmented board, the colors will really pop
when they are glossed and polished. The process requires some specialized
materials and tools (all borrowed from the automotive finishing industry), all
of which you can get in Greenlight’s Gloss/Polish Kit.
Glossing/polishing epoxy has always been considered more difficult than doing
it on polyester resin, but the truth is, you can get a really nice shine on epoxy
by using a few higher grits of sandpaper before switching to your compounding
Brushing on your Gloss Coat
process for applying your gloss coat is nearly identical to applying a hot
coat. Since you already have a smooth, sanded hot coat, you need a little bit
less resin for your gloss coat. Still, plan on about 1oz of mixed material per
foot of surfboard length, and don’t forget about your 2 capfuls of Additive F
to help the resin flow evenly on the board. Just like hot-coating, you want to
tape off your rails with high-temp masking tape to keep drips from
running down the rail. Also, if you aren’t satisfied with the sharpness of your
tail edge, you can use the gloss coat as a second chance to square it up with a
small tape-dam in that area.
little trick while glossing is to use a razor blade to scrape away the bump of
epoxy left along the tape border once the epoxy has set up and is no longer
tacky. It is easier to scrape away this small line of epoxy when it is soft
(but not sticky). Do this twice (after you have glossed each side of the
board), as it will make your final sanding/polishing step easier.
Fine Sanding the Gloss Coat
your gloss coat has cured, you should have a nice, shiny flat finish that is
ready to sand. Since you did a lot of the rough sanding on your hot-coat, you
start sanding your gloss coat with higher grits. Most glossers start with 320
grit and remove the shiny surface first (don’t worry, it will come back). Make
sure to keep your sandpaper as clean as possible, brushing the buildup off with
a wire brush. Once you have sanded away the shine, you need to work your way up
with progressively higher grits of sandpaper. Each grit removes the scratches
left by the previous grit.
320 grit, move to 400, still using your power sander. You may
also want to start wet-sanding at this stage. From 400 grit, you may want to
switch to hand-sanding with a soft or medium sanding pad. The
progression of grits should be: 600, 800, 1000, 1,500, and finally 2,000. You
should wet sand all of these grits, as it helps keep the sandpaper clean and
cutting evenly. Run your sanding pad nose to tail and tail to nose during these
stages. You want to avoid going rail to rail or in circles, as you are just
trying to remove the fine scratches from the previous grit.
you have wet-sanded to 2,000, it’s time to break out your wool compounding
bonnet and compounding liquid. You need to use your variable speed
sander/polisher for these final steps. The goal with the compound is to
squirt it on the board and spread it around while it’s still in liquid form.
Typically you work in sections with the compound, spreading it around and
buffing the board until the compound dries in a haze. Once that section is dry,
move on to the next section. Finally, when all of the sections are dry, you
basically buff off the compound with your polisher/sander. Don’t forget the
rails. You should be covering the entire board with the compound. You can do
the whole thing with the power polisher. No need to hand-compound at this
stage. Once the compound is buffed off, hand-wipe the entire board with a microfiber
cloth to remove any compound residue before you start the polishing stage.
The final step in
the process, polishing requires use of a polishing compound (finer grit) and
polishing bonnet (typically foam). Besides these two components, the polishing
step is essentially the same as the compounding step. Work section by section,
and don’t forget the rails. Once the polish has dried to a haze, you buff it
off with your polisher and you won’t believe your eyes. The board should be
back to it’s original post-gloss shine. At this stage, take one final pass with
your microfiber cloth, and you are DONE.