Appropriate materials should be used in the repair of slider soundboards, especially as concerns pallet coverings and springs, pull-downs, pull-down seals and slide lubrication. Where upperboards are held down with old or unusual screws or even nails, these should be kept and matched to their holes. Where flooding is needed, the glue should be carefully matched to the original material; synthetic glue should not be used where natural glue was used originally. Slides running in leather should be restored. The repair of split or lifted tables and warped slides and upperboards should be carried out with care, using the minimum of additional material or screws, and the minimum of planing or grooving away of timber. A certain amount of minor running may be allowed where the alternative would involve the loss of considerable thickness in tables, slides or upperboards. Slide seals should not be fitted where not already present.
Sliderless windchests, where they survive as part of an organ being restored, should be restored to their original state using the same care over materials and techniques as would apply to a slider soundboard.
Wind supply system
Original feeder bellows, reservoir bellows, regulators, wind trunks, concussion bellows and other components that determine the wind characteristics of the organ should be retained and restored where necessary. Reservoir bellows winding systems should not be replaced by other types of regulators because the sound of the instrument will be affected. Double-rise reservoirs should not be releathered in single rise form. Hand-blowing mechanisms, where these survive, should not be removed, even if not restored to working order. The retention or addition of a rotary fan blower does not detract from the value of an historic organ if it causes no alteration to the winding system or to the case or the structure of the organ. However there is some difference in sound between hand blowing and electric blowing.