Using woodstains
When woodstain is being used the following points should be noted:
- Timber glazing beads can be a problem as they normally have different expansion/contraction rates from the surrounding frames - when possible use aluminium beads particularly on horizontal members as they are much more stable.
- For bottom beads use aluminium in non-setting mastic - this is best for long-life performance.
- Conventional glazing systems set in linseed oil putty should not be used - they are too brittle. Use a glazing compound flexible mastic or aluminium-bead glazing with suitable depth of rebate. Gaps must be filled with a silicone sealant.
- Refer to the Glass and Glazing Federation or a glazing manufacturer for information on the choice of glazing systems available.
- Due to the difference in solids content between paints and woodstains the ability of a woodstain to seal and bridge joints is greatly reduced. To overcome this problem joints should be sealed with a suitable mastic during manufacture.
- As woodstains are more permeable than most paint systems fluctuation of moisture content in plywood can result in water-soluble salts present in the adhesive being brought to the surface. These are normally washed off by rain but if an area is sheltered from direct rainfall (such as under the eaves) white deposits may build up and mar the surface. These salts can be washed off but will reappear until they have all migrated.