Working with Hardboard

When boards are delivered, store them flat and fake care to protect the corners and edges from damage.

Normal woodworking tools are used for cutting, shaping and cleaning up the edges. Avoid damaging the surface; once the smooth top crust is broken, no amount of sandpapering will repair the damage.

The surfaces of all except the medium and plastic-coated hardboards have a ripple or hammer texture which shows up after painting. Nothing can hide this, but it will be less noticeable with matt or eggshell finishes, which are less reflective than gloss.

Conditioning

Where standard hardboard is to be used, the manufacturers recommend that you should condition the board to prevent possible buckling through a change in moisture content. This is especially important if using the board as an underlay to floor tiles etc.

To condition the board, lay it flat on the floor and scrub cold water into the back at the rate of 1 litre (2 pints) to every 2440 x 1220 mm (8 x 4 ft) sheet. Leave the board flat on the floor for 48 hours to adjust itself to the moisture conditions in the house. Leave tempered hardboard for 72 hours.

Do not condition boards in this way if they are to be fixed in surroundings where there is continuous heating; instead, allow them to dry out to the level of the surroundings for 72 hours.

Cutting

Use a fine-toothed saw (a tenon saw is ideal), and always cut on the face side.

On pre-painted and plastic-covered boards, score the cutting line with a knife before sawing; this prevents the top skin from chipping.

To prevent any tear-away, support both ends of the sheet on the underside.

Take your time when sawing; do not force the saw, or it will either tear the sheet or jump out and score the surface.

Cleaning up

Planes, spokeshaves and abrasive papers all give a good finish to the edges of standard hardboards. On medium hardboards, use only abrasive papers.

Avoid damaging the top surface.

Gluing

All woodworking adhesives work well on untempered hardboard. If gluing to the face of the board, rough-up the surface of the board to give the adhesive a key.

Fittings

hardboard pins

Always drive screws through hardboard, not into it.

When pinning, use hardboard pins which are specially designed with diamond-shaped heads to penetrate the tough skin and leave a neat indent which can easily be filled.

Panel pins tend to stand above the surface and are always evident through painted finishes.

Painting and papering

All hardboards except factory-finished ones must be primed with special hard- board primer or thinned emulsion paint.

Use one part of water to four of paint.

Prime steel screws and pinheads before covering them with emulsion paint, otherwise they will rust and show through.

Seal hardboard with a coat of hardboard primer before hanging wallpaper on it.

Underlaying

Use sheets not larger than 1220 x 1220 mm (4 x 4 ft) and stagger adjoining rows so that joints do not coincide. Fix hardboard to wooden floors with annular nails every 100 mm (4 in) at the edges and at 150 mm (6 in) spacings elsewhere. Lay the mesh side uppermost, to hide the nail heads, except when thin vinyl tiles are to be bonded to the hardboard.

For many woodworking hints and tips from Ted ‘Woody’ Mcgrath – Professional Woodworker, Educator, Member of AWI , Please Click Here!

 

27. June 2011 by admin
Categories: Timber, Woodworking | Tags: | Comments Off on Working with Hardboard

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