Hardwood - Varnishes and Translucent Wood Finishes
Hardwood New
Varnishes and Translucent Stain Finishes.
While hardwoods are often allowed to weather naturally others prefer to treat the wood with either varnish or translucent wood stains.
Preparation.
All surface contaminants should by the most appropriate means followed by sanding down with suitable grade of glass- sand or garnet paper to prove a smooth surface.
Any visible resin around knots or sap residue should be removed and the surface wiped over with methylated spirit. When dry two thin coats of a white shellac
knotting.
Clear shellac should be used over any knots or sap residue.
All making good should be carried out with an appropriate wood filler and tinted to match the surrounding surface and sanded down.
Painting.
Apply one sealer coat and two full coats of the selected coating following the manufactures instructions
Note: If a normal coloured shellac knotting is used the shade will mirror through any subsequent clear or tinted finish.
Linseed oil putty should not be used for glazing or filling. Alkyd based sealants are recommended
Any discolouration of the bare wood due to weathering or water attack can be difficult to remove but treating the area with Oxalic Acid may remove the discolouration.
See: Problems and remedies Flaking of Stained wood finishes.
For further product information:
https://www.liberon.co.uk/product/palette-wood-dye
https://www.zinsseruk.com/product
Graining Tool Box
For further information on Graining tools and equipment:
H S Handover Ltd. Tel: 0207 2415877 - www.handover.co.uk
Gilding Tool Box
For full information on Tools and Equipment contact: A S Handover Ltd at: http.//www.handover.co.uk
Corroded Aluminum
Aluminium Corrosion
Cause
Although naturally resistant to corrosion when untreated aluminium is exposed to the external weathering a thin layer of oxide forms on the surface and enhances the resistance to corrosion.
However, this thin layer of oxide while being insoluble in water and resistant to some chemicals, it does not prevent the aluminium from loosing its glossy appearance and becoming dull.
Corrosion attack can occur if aluminium comes in contact substrates such as new concrete and other building components which have a alkaline content. Additionally, contact with other metals such as copper, lead, iron and copper naphthenate used as a wood preservative should also be avoided. Contact with sulphuric and hydrochloric acids along with chlorinated based solvents should also be avoided.
Remedy
See: Specification for Galvanised steel.
Broken Colour Techniques
Special Effects
Rag Rolling.
This effect is obtained by rolling over a newly applied coat of glaze a onto a previously applied base colour with either clean rag, or polythene twisting the rolling motion to produce a marble type appearance.
Stippling
A decorative effect achieved by applying a wet coat of glaze over a base coat colour and tapping the surface with a stippling brush.
Sponging Off
This paint effect is achieved by using a slightly moist natural sea sponge which is tapped across the newly applied coat of glaze removing some of the newly applied wet glaze coat.
Sponging On
This design is created by using a natural sea sponge which is then dipped into the glaze then tapped over the surface turn the hand in different directions to produce the required pattern and texture.
Colourwash
This mottled effect is achieved by applying a glaze coat over a coloured base coat in different directions then with a brush lightly glide over the surface to soften the appearance.
Bagging
This is effect is achieved by taking a crunched up piece of polythene to form creases and tapped onto the wet glaze coating.
Dragging
This is a paint effect is produced using a dragging brush ( as in graining) which is pressed into the wet coating of glaze to form straight lines.
Frottage
This effect is created by taking lining paper (800 grade) crunched up then opened up and laid out and placed over
a wet coating of glaze and finely smoothed over with a brush.
Leather Roller
This type of roller is formed by taking cut pieces of chamois leather screwed into a roller sleeve. Once formed the roller is then used to run over a wet coating of glaze in various directions to produce the required pattern.
Woodgrain effect
This grain effect is produced by using a graining rocker.
See. Broken Colour Toolbox under Tools and Equipment and Specifications -Broken Colour Techniques
Blistering
Blistering
Cause
Generally blistering is caused by moisture ingress into the underlying substrate. In time this builds up behind the paint coating resulting in blisters forming and in many cases, when broken, contain water.
In other cases blisters can form in and around wood knots and these can be as a result of gases from hardwood knots and sap.
Solution
The cause of the water ingress should be determined and rectified.
Note: Where wood knots are present then these should be either cut out and replaced with sound wood or two pack wood filler and suitable primer. For hardwood surfaces a spirit based aluminium wood primer could be used.
Shellac knotting will not resolve blistering problems as it is only designed to isolate the tannic acid, preventing it coming into contact with oil based alkyd paints to preventing discolouration. (see yellowing)
Complete removal of all the existing coatings and repaint with a standard system for wood.
Flaking on Under Bound Surfaces
Under Bound Surfaces
Cause
Flaking is due to the underlying material being under bound Material which in case is old distemper
Solution
Complete removal of all the coating should be removed back to a sound surface.
Patch repair and painting is not advisable.
Personal Protective Equipment (PPE)
PPE (Personal Protective Equipment)
Throughout the Building and construction industries it is mandatory that all employees wear suitable PPE at all times.
The type of PPE required will depend on the functions being carried out and will be made known either
by standard site notices or specific instructions issued by the employer.
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