Decorating: Preparing Wood and Metal for Painting

Woodwork and Metalwork

Unlike painted walls, painted woodwork is often better stripped before you redecorate: built-up layers of oil-based paint will prevent your newly decorated woodwork from looking crisp and even. However, if the woodwork is in good condition you can simply clean and degrease it, then lightly sand it down to provide a key for painting.

Metalwork — window frames, for example — can be treated in exactly the same way. If there is rust you should clean this off with an emery cloth or a wire brush.

 

Wooden floors often require special attention. Boards may need replacing, levelling or fixing down. Also, it is important to fill gaps and sink nail-heads if you are planning to sand, varnish or stain the floor.

 

Stripping Woodwork

The three main methods of stripping paint from woodwork are scraping, the use of chemicals, and the application of heat.

If you work with chemicals, make sure to wear protective gloves and glasses. If you use a hot-air stripper, do so with care, especially when stripping window frames: excess heat can cause the glass to crack, and there is a danger of scorching the wood or setting the accumulated paint scrapings ablaze.

 

Heat Stripping

Use a hot-air stripper to soften paint. Move it to and fro, scraping away paint either with a scraper for flat areas or with a shave hook for mouldings.

 

Chemical Stripping

Dab on liquid stripper with a brush. When the paint has softened and bubbled, scrape it off using a shave hook on mouldings (pulling towards you) or a broad scraper on flat areas (pushing away from you).

This is the best method of stripping window frames but it can be expensive, messy and time-consuming.

 

Sanding

On flat surfaces you can strip paint with an orbital sander, but it can be extremely dusty and messy. For mouldings, use a flexible abrasive block for the job.

 

SURFACE TREATMENTS:

New Wood

Use cellulose filler for cracks and holes. Cover knots with shellac knotting. Smooth the surface with a fine abrasive paper.

 

Old Wood

Make sure that there is no sign of rot, and fill cracks and holes. Smooth with a fine abrasive paper.

 

Painted Wood

If the surface is in good condition, clean with sugar soap and water. Rub down with a medium-grade flexible sanding block or abrasive paper to provide a key for the new paint. Cracked paint should be stripped.

 

Varnished Wood

Use varnish stripper in order to get back to bare wood.

 

Stained Wood

Wood bleach can be used to remove stain. If the surface is to be painted, rub with a medium-grade flexible sanding block or abrasive paper. Wood stain protected by varnish must be removed as above.

 

Painted Metal

Clean with sugar soap and water if in good condition. Otherwise, use a wire brush to remove flaking paint, and treat rust with a primer containing rust inhibitor.

 

Aluminium/Copper

Clean with white spirit and apply enamel without primer or undercoat. Use flour-grade paper to remove signs of corrosion and scratches.

 

Replacing a Floorboard

1. Lever up the damaged board with a bolster chisel (brick chisel). If you cannot lift a whole board, cut out a short piece. First drill a starting hole and then cut across the board with a padsaw (keyhole saw) alongside, but not cutting into, a joist, pipe or cable.

Loosen nails by slipping a strip of wood under the board and pressing down hard on the end. Repeat the process, jamming the wood strip up as far as it will go, until the board is free.

2. Screw a short wooden batten to the side of the joist, flush with the underside of the floorboards. Cut the replacement board and nail to batten.

 

Adding Door Mouldings

Flush doors, cupboard fronts and kitchen units can be dressed up by applying ready-made wooden mouldings to provide decorative detail. There are sets available especially for this purpose, allowing you to create the effect of traditional panelling. These come in sizes to suit standard doors, and are available both curved and straight; the corners are mitred. To attach them, drill very fine holes in the moulding and fix with pins.

Alternatively, you can use ready-made wooden mouldings to make your own picture rail or dado rail, fixing it in position with masonry nails or screws.

01. June 2011 by admin
Categories: Decorating, Painting | Tags: , , , | Comments Off on Decorating: Preparing Wood and Metal for Painting

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