Making it Shine

Shine is lots of light reflected back to the viewer. The more light is absorbed by a surface, the less shiny it appears. The smoother a surface, the more unidirectional the reflected light, the more shiny. Picture a sandy beach: the dry sand consists of bezillion little facets, reflecting the light into bezillion different directions. It looks dull. Now a wave comes along, and coats the sand. The surface is smooth, reflects much more light back at the observer, and appears shiny.

When you are first done with a repair on your board, you will have smoothed things with, say, 220grit sandpaper. Even with the bare eye, you can see major scratches. The surface is broken into many different facets, all reflecting the light into different directions - it appears dull.

To go from this to a glossy surface takes nothing more exotic than sandpaper, polishing compound, and lots of patience provided the material is hard enough we'll get back to that later.

The object is to reduce the scratches in depth, so that a bigger and bigger percentage of the surface is uniform, reflecting the light uniformly.

Throughout the finishing process, never ever sand with your bare hands, but always use some backing block - the softer, the finer the sandpaper.

Scratches left by 220 grit paper are best tackled with 400 grit wet & dry paper, flushed often with water to prevent debris from scratching the surface. Keep sanding until all the 220 grit scratches have disappeared.

If you sanded in a fore and aft direction with the 220, and follow on a left-slant 45 degree angle with the 400, you can see exactly when the fore & aft scratches are gone. Next, sand the 400 grit scratches with 600 grit wet & dry on a right-slant 45 degree angle. You are good when the left-slant 400 grit scratches are all gone. Follow with 1200 grit wet & dry again going fore & aft, until all the right-slant 600 grit scratches are gone. By now, the surface is uniform and has a satiny appearance.

Most folks go from here straight to a rubbing compound. But there is a quicker, more reliable way: more wet-sanding with Micro-Mesh foam-backed sanding pads. These come in amazingly fine grades (I use from 2400 to 12000 grit), which will take your satiny surface to near-gloss in no time, without the chance of burning that machine-compounding has.

 
Next, a polishing compound will bring out some shine

a swirl remover will deepen it, and a machine glaze top it off brilliantly.

As you switch from one compound to the next make sure to switch to the appropriate foam pad as well, and clean your applicator!

a lot of work - but wasn't it worth it??

Can any surface be made shiny in this way? No! The cell structure of the material may be so coarse as to always refract the light every which way. Most very light-weight materials are like that: you will for example not be able to make a piece of fir glossy (without a coating). Many plastics (including the ASA skin on boards) will never be glossy. Even some paints fall into this category, particularly those that come out of rattle-cans. As a matter of fact, the touch-up paints sold by a very prominent surfboard manufacturer simply disappear when attacked with a polisher. So - if in doubt - do test an inconspicuous area first!

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