Finishing - Finishing without Pricey Power Tools

A question in the Indian DIY forum (http://www.diyable.net) prompted me to write this post on finishing by hand. The question was about what kind of power sander is needed to make sanding easier. My simple answer was that power sanders are not required for a hobbyist woodworker. Reason: hobbyists have time on their hands and usually tackle relatively small projects. Hand sanding is just fine and gives the hobbyist more control over the sanding process.

Here is a quick account of how I usually go about finishing my projects.

When working with wood (as opposed to plywood or board) I flatten and prepare my surfaces with hand planes. This means I do not have to do major stock removal.
If major stock removal is required, that is, if the surface is undulating or marred, use a long flat piece of wood (about 10 inches long) with a cork or rubber (from any discarded tyre tube) backing. Cut sandpaper to size and attach with brass drawing pins. A tote, like that of a hand plane, attached to the sanding board would make things easier. Use 40 and then 80 grit sandpaper. This will leave you with a pretty rough surface but a flat one.

Sanding

For regular sanding, use a smaller wooden block or foam, one that will fit comfortably in your hand. Cut out a piece of sandpaper and wrap it around the sides of the block. Start with 120 grit and finish with 180 grit. Anything more would be overkill. If you want a mirror finish, go up to 240 grit but not more.

Foam Sanding Block with sandpaper

The other grits 320 upwards are used for polishing the top coat and not sanding wood.

Staining

These days I mostly use water based dyes for staining. They are cheap: cost less than a hundred rupees for a little jar full which will last for a long time. Best thing about water based dyes is that they are easy to handle and give a good even colour to the wood.

Water based dye

After Staining

I take a plastic cup with tap water in it and add a tiny amount of dye, mix well and let sit for about 15 minutes. I use a cheap brush to apply the stain.

Seal Coat

After the stain has dried (an hour or two), I sand lightly with 320 grit paper and then coat with a dilute Shellac solution. This is the seal coat, which I let dry for at least 3 hours.

Grain Filling

Generally, especially if the wood is not too porous or grainy I skip the grain filling step and go directly to top coating.

When I want to get a mirror polish I use chalk powder, available at any local paint shop, mixed with water and a bit of stain as grain filler. The resultant slurry needs to be applied generously then scraped off. After it has dried (3-4 hours), the surface is sanded with 320 grit paper and wiped clean.

After Grain Filling with Chalk Powder

After it has dried (preferably overnight), apply a couple of coats of Shellac ( or PU) and see what it looks like.

Shellac Coat after Grain Filler Has dried

Glaze Coat

If the pores in the wood are very deep and pronounced as in this piece of Teak, then the chalk filler will stand out. This effect may not be what one is after. In that case, another glaze coat of dye or stain will give a more even colour and reduce the contrast with the light coloured chalk grain filling.

After a Glaze Coat

Top Coat

I stick to Shellac or Polyurethane (PU) for top coating. I was not too happy with Varnish when I once tried it and have never used lacquer, which are two other widely used types of top coating.

For Shellac, I apply 4 to 5 thin coats, sanding with 400 grit paper in between coats. I generally allow each coat to dry before applying the next.

After four coats of Shellac

With PU three coats are generally enough but with water based PU more coats are required. Light sanding between each dried coat is absolutely essential.

Polishing

It is best to let the top coat cure for 2-3 days in the case of Shellac and at least a week in the case of Pu before polishing it.

Polishing and Rubbing Compounds

For most Shellac top coats, I use 3M polish, which is a creamy liquid that has to be buffed after it has dried somewhat - gives an excellent finish. There are more elaborate ways to polish or rub the finish, such as the methods that use pumice and rottenstone, but that is a subject I am not very familiar with.
Paste or furniture wax (made by 3M, Waxpol and so on) is another alternative and after applying should be allowed to dry for at least 15 minutes before buffing with a soft cotton cloth. The more you rub, the higher the sheen.

PU needs to be polished with progressively higher grits of sandpaper - starting with 400 and continuing till 1500 or more - for a mirror finish. A rub down with rubbing compound (also available from a number of manufacturers including 3M and Waxpol) will give a nice satin finish.

My dovetail box with a Shellac finish - the piece I had shown being polishing is the panel on the top.

Secret of a Great Finish

Two secrets really - one is patience and the other is experimentation. Most finishing materials are relatively cheap and readily available. Get cheap wood, even packing case material, plane it down well, and then try various finishes and different levels of polishing.

Warning

Finishing can get addictive! For the last one year, I have been stripping the finish off my old furniture and re-finishing them using various recipes. The results have been mixed but nobody has complained.

Indranil Banerjie
10 January 2014