Ten Useful Chemicals for Woodworkers

Most commercial cleaners, household de-greasers and paint thinners contain one or more basic chemical. It is better to know what those chemicals are and their uses. The branded products tend to be far more expensive than the basic chemicals they are made from and often it is best to use the unmixed variety for most woodworking uses. Here is a list of some of the more useful ones:

DENATURED ALCOHOL
This is also known as Methylated Spirit. This compound is ethanol mixed with about 10 per cent of the poisonous Methyl Alcohol and other compound such as Acetone. The idea is to make potable alcohol undrinkable. This procedure is mandated by governments who fear they would lose revenue if people took to drinking ethanol instead of the heavily taxed liquors such as Vodka and Rum. Ethanol, in any state, is extremely useful for a variety of processes and is the best solvent for Shellac. It is also useful for general purpose cleaning, removing ink stains from fabric, as a lubricant while sanding wood and so on. A litre costs Rs 50.

ACETONE
This is a very useful solvent, cleaner and happens to be the active ingredient in nail polish remover. It is present in many paints and varnishes as a thinner and therefore can be used to clean paint brushes after use, rubbing off paint, glue and even epoxy. It is a great de-greaser as well and should be used to wipe metal parts prior to painting. Keep a half litre jug around the house for a variety of tasks, including general cleaning. Old porcelain can be cleaned and made to look like new with Acetone. Other uses include removing stickers from glass, dissolving superglue and remove melted plastic. A litre costs about Rs 110.

NAPHTHA
Naphtha is a colourless petrochemical product lighter than petrol. It is a very strong and versatile solvent and is used to thin and clean oil based varnishes, paints, enamels. Naphtha can replace paint thinner and will help accelerate drying time of oil based paints, enamels and varnishes. It should not be used with lacquers, shellac or latex paint. Naphtha is also an excellent general purpose cleaner. Keep a litre or so around for use during painting and varnishing.

PARAFFIN OIL
This petroleum based liquid is also known as mineral oil or as mineral turpentine in some countries. Some varieties are lighter than others. It is an ingredient in many paints and stains. The heavier varieties can be used for the final sanding in the finishing process. Traditionally, it was combined with pumice or rottenstone to produce slurry that could be rubbed over the final surface. It can also be used with higher grit sandpapers of 600 and higher grits for a mirror finish.

NITRO CELLULOSE (NC) THINNER
This compound made up of several organic chemicals including ketones, alcohol and so on is specifically meant for thinning lacquers even though in many parts of India it is sold simply as "spirit" and a general solvent for paints. NC thinner should not be used to prepare Shellac or thin paints. Shellac is best dissolved by Denatured Alcohol while paints and varnishes are best thinned with Turpentine or Naphtha.

TURPENTINE
This useful paint thinner was originally obtained from naturally occurring resins, mainly from pine trees. Today a lot of Turpentine is actually substitutes made from petroleum. These substitutes tend to be less effective than the real thing and are usually odourless. Genuine Turpentine is the best thinner for paints and varnishes. Wax polish too can be made by mixing Turpentine with carnauba or bees wax. There are many qualities of Turpentine and a lot of it in India tends to be adulterated with kerosene.

TRI-SODIUM PHOSPHATE (TSP)
TSP is an awesome cleaner and no woodworker or householder should be without a kilo or so of this powder. This is basically a very powerful detergent and can remove grease, oil stains, cooking oil build-up and dirt off painted walls. For these purposes a very dilute (about 10 per cent) solution should be used. TSP is great for rubbing down old paint as on doors and windows prior to re-painting. A dilute solution will also clean tools well (the tools should be rubbed with WD-40 after they dry). For really tough stains use TSP as a paste mixed with water. Most commercially available detergents and household cleaners have some percentage of TSP in them.

OXALIC ACID
I picked up half a kilo of oxalic acid crystals from a chemical store in Delhi. It is pretty cheap - Rs 40 or so. This stuff is somewhat poisonous and should be used with some care. The crystals dissolve easily in water and can be brushed on to wood to bleach it. After the wood has been bleached, the oxalic acid would have dried into a fine white powder over the wood. This should be washed off and cleaned with a dilute alkaline cleaner like TSP. Oxalic acid is also great as a rust remover.

DICHLOROMETHANE
This chemical is also known as METHYLENE CHLORIDE. It is a highly volatile, colourless liquid and has many uses, including that of a paint stripper, solvent for plastics, for decaffeinating coffee and for welding plastics including polycarbonate. This is powerful stuff and is the basic ingredient of all plastic cements. Keep some around for joining plastic.

AMMONIA
Ammonia is a gas and cannot really be used in that state by the average hobbyist. What is used instead is "Household ammonia" or "ammonium hydroxide", which is a solution of NH3 in water. Higher concentrations of ammonium hydroxide (30 per cent or so) is required for fuming woods to turn them darker. Get a large corrugated paper box like the ones used to transport refrigerators, pour some of the ammonium hydroxide in a dish and place it inside the box along with the wood to be fumed. The box should be closed on all sides. After 5 hours or so the wood would have darkened to a beautiful hue. This wood can then be finished with Shellac, oil or whatever finish of your choice.
Ends

Indranil Banerjie
27 October 2012

Comments

  1. Once again, a very useful post.

    I'd suggest that if you know of Indian names of these products then you mention them as well. You've already bought few of these chemicals and you would've an idea of what they are called in local dialect. I think it'll be of tremendous help to fellow Indian DIYers.

    ReplyDelete
  2. To Criminal: Unfortunately there are no Indian names for the chemicals. Even Turpentine is called Turpentine or at best Turpin Tale.

    ReplyDelete
  3. Anonymous09 July, 2014

    Hi Indranil,
    Very useful info. Thanks a ton! - Shree

    ReplyDelete

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