Paint and Varnish Stripping Methods

PROFESSIONAL STRIPPING METHODS

Although fast and effective, these methods can ruin an item if used inappropriately. Always choose a reputable outlet and ask to see items that they have recently stripped.

Caustic dipping: One of the quickest methods of stripping any finish on wood is by caustic dipping. Look in the phone book to find your nearest outlet. Dipping is a very harsh method, which should only be attempted if it is impossible to use other stripping methods, or if you have a large number of doors or banister spindles to strip. The drawbacks of caustic dipping are that it can dissolve glued joints, warp the wood and give the item a bleached appearance, although this can be corrected to a certain extent with wood restorer after treatment.

Sandblasting: This is another method that cannot be attempted at home. It is usually used to strip paint from metal and masonry. The technique involves particles of sand being fired at the item at a high velocity to strip away the surface. It is not suitable for delicate items but is useful for large areas. It is often used to clean dirt and pollution damage from buildings.

STRIPPING METHODS

Time taken at this stage will reveal the true state of the item beneath and allow repairs to be made.

STRIPPING WITH A HOT-AIR GUN

Suitability: stripping oil-based paints and varnish on wood and metal. They are widely available to buy or hire; the most effective models have variable temperature settings and come with a scraper attachment, enabling you to use the tool with one hand and leaving the other hand free. Because the gun rapidly heats up the paint, perform a test patch to gauge the length of time the heat should be applied.

Advantages: speed and cleanliness. Cost-effective method over large areas, such as doors.

Disadvantages: care must be taken near glass and there is a high risk of scorching the wood. Expensive if you only have one item to strip. Floors should be protected and singed paint swept up and disposed of carefully once cool.

•Hold the gun with the integral scraper blade resting against the painted surface at an angle of 30-40 degrees. The paint will soften and bubble almost immediately and should be scraped away in one continuous movement.

STRIPPING WITH A LIQUID JELLY PAINT/VARNISH STRIPPER

Suitability: all types of paint, varnish, lacquer and shellac-based finishes, although equally effective on wood and metal.

Advantages: a quick, effective method on one to three coats of paint or varnish. Works well on detailed mouldings as the jelly can penetrate the nooks and crannies. Most effective on horizontal surfaces. New formulations of liquid stripper do not contain methylene chloride or methanol. This makes them low odour’ and more pleasant to use.

Disadvantages: will need to be reapplied on heavily over-painted items. This is an efficient, if slightly messy, technique so make sure the floor surface is well protected. The liquid jelly consistency can run off vertical surfaces. The materials will be relatively expensive if you have large areas to strip.

•Apply with an old paintbrush then test with a paint scraper to see if the paint comes away easily.

STRIPPING WITH A PASTE STRIPPER

Suitability: a fairly clean method for stripping wood and metal items.

Advantages: its thick consistency enables it to cling to vertical and overhead surfaces, as well as covering intricate shapes.

Disadvantages: needs to be washed off/neutralized with water, which makes it unsuitable for veneered items. It can slightly darken the colour of wood and can be tricky to apply evenly to awkward shapes.

•Working times will vary so follow manufacturer’s instructions, then test a small area before you start.

STRIPPING WITH A PEEL-AWAY BLANKET STRIPPER

Suitability: an excellent method for wooden, metal, brick and stone surfaces that have been over-painted many times. Because it is neutralized with water it is not suitable for use on veneered surfaces. Fairly expensive to use over a large area.

Advantages: removes paint cleanly leaving very little residue. Needs virtually no scraping, which makes it a good choice for delicate or easily scratched surfaces. Once applied, you simply wait for the paint to solidify onto the blanket, then lift it away.

Disadvantages: it can take several hours to work and is slightly messy to remove. It can be tricky to use on vertical and shaped surfaces because it is important that the blanket makes contact with all areas of the paste. It will sometimes need to be cut to fit large, bulky or awkward shaped items. On some porous surfaces, peel-away blanket stripper needs to be neutralized with a special solution.

STRIPPING WITH A CABINET SCRAPER

Suitability: can be used to remove gloss paint and most varnished finishes on wooden surfaces.

Advantages: the cheapest stripping method. Removes paint and polishes the wood beneath. Works well on awkward areas such as glazing bars and beading. Good as a finishing technique used with another stripping method.

Disadvantages: time-consuming and tricky as it needs constant pressure making it hard on the hands. The rolled steel blade needs to be kept sharp if it is to work properly.

STRIPPING WITH AN ELECTRIC SANDER

Suitability: works well on painted and varnished wooden surfaces that are to be re-painted. The multifunctional sanders are particularly useful as they combine different shaped bases for orbital sanding, as well as different shaped profiles for sanding a variety of shapes including spindles and mouldings.

Advantages: a fairly quick and efficient method of stripping. It is ideal for keying a painted surface ready for re-painting.

Disadvantages: a harsh method, which removes the surface of the wood as well as the finish. It produces a great deal of dust, so make sure the room is well-ventilated and wear a face mask; if possible perform sanding outside.

STRIPPING WITH WOODEN FLOOR CLEANING SOLUTION

Suitability: only for floorboards with a waxed finish that are in relatively good condition.

Advantages: a gentle method leaving the surface of the wood intact. No hiring costs for sanding equipment.

Disadvantages: a time-consuming method. It will not remove paint or varnish finishes.

STRIPPING WITH A HEAVY-DUTY SANDING MACHINE

Suitability: can be used on all varieties of solid wooden floorboards and parquet floors.

Advantages: this is the quickest and most effective method of stripping back to bare wood. Different kinds of belt sanders and edging sanders are widely available for hire from DIY outlets.

Disadvantages: it removes the top layer of wood leaving the floor looking too new with none of its natural patina. An enormous amount of dust is produced: seal up doorways with polythene sheets and open windows for ventilation. It is very noisy: wear ear plugs and warn neighbours.

HINTS AND TIPS

Once you have stripped the floorboards, seal them with a finish as soon as possible because the untreated wood will mark easily.

STRIPPING WITH WHITE SPIRIT

Suitability: removes wax and oil finishes on wood.

Advantages: it is a gentle but effective stripping method.

Disadvantages: it only works on items that are finished with wax or oil, not any harder finish. It also has a drying effect on wood that can leave it looking dull.

STRIPPING WITH METHYLATED SPIRIT

Suitability: removes shellac-based finishes from solid wood.

Advantages: the gentlest method of removing traditional French polish and other shellac-based finishes.

Disadvantages: it does not work with other finishes — veneered items, in particular, as the water content of the spirit raises the grain. It is a fairly messy process because the polish becomes very sticky.