Polish

A Once you've laid down a thick film of finish, it only takes a small amount of elbow grease to level it. The three ingredients you'll need are wet-or-dry sandpaper, a padded sanding block, and plenty of mineral spirits.

Sanding near the edges gets my special attention. It's often where the finish is the "roughest" and needs the most work. But you want to take care not to sand through the finish to bare wood. I try to use a light touch and not "drag" the sanding block too far over the edge.

CHECK YOUR PROGRESS. I use both sight and feel to check my progress. When you run your fingers lightly across the surface, you'll feel any unevenness. Then after sanding for a time, I'll wipe the surface clean and look closely for shiny areas. Spots of shiny finish mean your surface isn't quite flat. You want a surface that's completely dull.

TIME TO SWITCH. When I think the surface is 99% flat, I switch to 1200-grit and finally 1500-grit sandpaper and repeat the process. These two steps create finer and finer scratches and reduce the amount of polishing you'll need to do.

By now, most of the leveling work is done, so you can get through these last stages pretty quickly. But you don't want to leave any deep scratches that will take a lot of time to polish out later.

It can be hard to judge when to quit sanding and move on to the polishing. When you think you're close, clean the surface with a soft cloth and take a look. It may sound strange, but what you're shooting for at this point is a perfectly flat surface with a consistent dull sheen and no noticeable scratches.

BRING UP THE GLOSS

So now you've taken the film of finish from uneven and shiny down to dead flat but completely dull. But you can bring it back to a high sheen in two quick polishing steps.

A LITTLE DIFFERENT. This polishing or rubbing process is slightly different from the wet sanding you just

Dead Flat The drawing above shows the goal of the wet sanding process. The built-up finish is now perfectly flat and ready to polish to a high gloss.

At this point, you've built up a thick, shiny film, but it's not perfect. You'll see brush and lap marks and dust specks. So after allowing the finish to cure for several days, the next step is to sand the film until it's perfectly flat. And when it's flat as glass, you can polish it to a high sheen.

WET SANDING

This sanding process is a little different. Here, you'll use very fine-grit "wet-or-dry" sandpaper found at paint or auto body stores. The sandpaper is wrapped around a padded sanding block and the surface kept well lubricated with mineral spirits (paint thinner) while you sand. The mineral spirits float away the sanding dust to keep the sandpaper clean.

I like to start with 800-grit sandpaper. Just pour a liberal amount of thinner on the surface and start sanding with a circular motion. This "random" motion will get you to a perfectly flat surface quicker.

As you work, the mineral spirits and the sanding dust will mix to create a light slurry (photo above). This shows that you're making progress. It's a messy process, but even so, you want to keep the surface good and wet. On the plus side, you'll be surprised at how fast the fine sandpaper levels the irregular surface.

▼ The main tools for wet sanding to a smooth, flat surface are shown at left. Used with a sanding block, they'll get the job done suprisingly fast.

completed. Here, you'll use two traditional polishing abrasives — pumice stone and rottenstone — to remove the fine scratches left by the wet sanding. These abrasives (photo below) come in powder form and also need a lubricant to do their job. But instead of mineral spirits, the lubricant you'll use is a rubbing oil, like paraffin or mineral oil. The trick is that as you rub the surface, the abrasive powder and the oil combine to form a pastelike polish. (See page 49 for sources of these finishing supplies).

PUMICE STONE. The polishing begins with pumice stone as the abrasive. This comes in different grades or particle sizes (IF through 4F). But since the surface has already been

ptiMiCE STOr* *°ttensto^

ptiMiCE STOr* *°ttensto^

k The two traditional rubbing compounds you'll need to achieve a high gloss finish are 4F pumice stone and rottenstone.

Shop Tips A Brighter Shine

If you want to bring out just a little more gloss on your project, there's an easy way to do it. Stop by an auto body supply store and pick up a bottle of the swirl remover shown at far right. This easy-to-use product is a very fine, synthetic buffing compound used to give an auto paint job that "new car" shine.

You use the swirl remover similar to a paste wax (photo at right). Squirt some on a small area of the surface and rub with a soft cloth. Just polish until the swirl remover starts to dry out. When you clean the surface, you'll find an even brighter shine.

More Shine. In just a few minutes, you can bring up an even higher gloss. The automotive polish at right and a soft cloth are all you need.

Under the messy paste formed by the oil and the brown rottenstone powder, the finish is taking on its final mirror-like gloss. I put in a little extra time at this stage.

sanded with 1500-grit sandpaper, you can start polishing with the finest grade — 4F pumice stone.

First, pour out a small puddle of lubricating oil on the surface and then sprinkle a small amount of the white pumice powder over it.

Now I pick up a felt block to start rubbing (photo at right). A soft cotton cloth will do the job, but the felt block is easier to hold onto and gives you a large, flat polishing surface.

The key to the polishing is to take your time and be sure to cover the surface thoroughly. The direction of the rubbing doesn't matter, and a moderate amount of pressure is all that's needed. If the paste starts to get too thick and hard to rub out, simply add more oil and a little more pumice.

The polish works pretty fast. What you're looking for at this stage is soft, semi-gloss sheen. When you think you're there, clean an area with a soft cloth to take a look.

ROTTENSTONE. Once the pumice stone has done its job, you're nearing the end. Traditionally, the final step is to bring the surface to a high gloss by polishing with rottenstone. This is an even finer abrasive. (You can check out the box below for one additional step.)

Under the messy paste formed by the oil and the brown rottenstone powder, the finish is taking on its final mirror-like gloss. I put in a little extra time at this stage.

This final polishing step goes exactly like the one you just completed. The rubbing oil and brown rottenstone powder are spread over the surface and "rubbed" into a polishing paste. But before starting, wipe the surface clean of all traces of the pumice stone. And then switch to a clean felt block.

Again, you can rub in any direction, just concentrate on polishing every bit of the surface. And since this is the last step, I try to relax and not rush through it.

It's easy to tell when you've reached the mark. Pick up a fresh cloth and wipe the surface clear for a close inspection. If your gaze is rewarded with a sharp reflection, you're there — you've mastered a hand-rubbed, high-gloss finish. CI

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Wood Working for Amateur Craftsman

Wood Working for Amateur Craftsman

THIS book is one of the series of Handbooks on industrial subjects being published by the Popular Mechanics Company. Like Popular Mechanics Magazine, and like the other books in this series, it is written so you can understand it. The purpose of Popular Mechanics Handbooks is to supply a growing demand for high-class, up-to-date and accurate text-books, suitable for home study as well as for class use, on all mechanical subjects. The textand illustrations, in each instance, have been prepared expressly for this series by well known experts, and revised by the editor of Popular Mechanics.

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