Our tumble down house has progressed a long way since we first bought it and it’s got to the point where we need to start tackling the hectares of gloss paint that needs attention. Over the past 200 years or so most of the woodwork had been painted at least a dozen times or more so the fine delicate mouldings that nearly every piece of wood has on it have been obscured. To compound the problem just giving the paint a quick rub down and a re-glossing isn’t really an option, the problem is that at some point in the past most of the woodwork has been painted without getting a rub down first. This had lead to the paint flaking and peeling off in large strips as soon as it’s touched with a piece of sand paper. Even if a flake is very carefully sanded down it’s still visible under the new coat of paint as a sort of pockmark.
The first step, therefore, is to get the old paint off the wood without damaging the wood too much. I’ll focus on restoring a door but all the woodwork in a house is treated in a similar way. There are numerous ways to get paint off wood and which way works best in a given situation is very dependent on the type of paint covering the wood and how accessible to piece is. The following sections detail some of the ways and there benefits and drawbacks.
Sanding really is the just about the worst possible way to remove gloss paint from wood. The friction caused by sanding invariably leads to the paint softening and blocking the sand paper within a few moments. Even if you have very old and dry paint the amount of dust raised by sandpaper makes it an extremely messy way to remove paint. Sanding is best reserved till later in the process.
There are as many different types of paint stripper as there are types of paint. Paint stripper certainly has its place in the DIY tool kit but I don’t think it’s generally the best way to remove paint. The most common type of paint stripper in use at the moment by DIY’ers is based on a mixture of dichloromethane and methanol neither of which are good for you (dichloromethane is what causes the burning sensation followed by the numbness). You can also get paint strippers that are based around caustic soda and various other mixtures which work to varying degrees. Finally, paint stripper is pretty expensive even when bought in bulk.
Dip and Strip
There are numerous companies around that will offer dip-and-strip services. They take the door and submerge it in a bath of hot paint stripping chemicals. These services are very effective and will do a single door for about £45 (generally with sizeable discounts for multiple doors). The down side of dip-and-strip is the potential for serious damage to the door, the chemicals they use (normally caustic soda) will attack the glue in the doors joints and the door could fall to pieces. Stripped doors have become very popular, especially in Victorian houses, and it’s not at all uncommon to see most of the doors in the house in varying states of falling to bits. The only solution if the glue has failed is to spread the joints in the door, clean them up and re-glue them – a difficult task for someone without access to the correct equipment.
I find the heat gun to be the best way to strip large amounts of old gloss paint. I find that I can strip a dozen layers of paint off one side of a door in about 3 hours which will a 2kW gun costs about £1 in electricity. It’s a task best done in a very well ventilated area because no matter how careful you are you will burn the odd spot of paint and the fumes are not pleasant. Flat areas are easy and quick to strip with a heat gun. Moulding can also generally be stripped but you might find sharp edges tend to get a little singed because they are effectively been heated from two directions. Emulsions can’t generally be removed with a heat gun, they might sweat a little but generally they will burn before they come off. This doesn’t tend to be that much of a problem as they can be effectively rubbed down smooth.
My preferred technique is to heat an area till it blisters and then draw a hook type scraper towards myself. Rubbing backwards and forwards with the scraper should be avoided as it rubs the paint into the grain of the wood. You will find after a few hours that you are able to scrape one area of paint while heating another. Different types of paint respond differently to heating. Modern paints tend to blister and peel off nicely. Older paints tend to go sticky and require multiple scraping and heating cycles. Once the bulk of the paint is off I like to gently toast the nearly bare wood, this will raise the final oils from the old paint out of the wood and once scraped off the surface will be almost smooth enough for a painting again.