Advanced Mould work

Sample Questions 3 methods of copying the profile a cornice mould in situ Explain how casts are fixed together at joints of mitres Explain where the following mouldings would be positioned on a wall or ceiling,freeze, bean case, architrave, angle or staff bead, dado Explain what a core is and why it would be used Explain why a case mould would be required when making a hot pour rubber centre piece Explain in detail how to run a cornice in situ Explain how to construct a niche in situ include a perimeter moulding

materials Shellac Alum Oil & Grease Pvc Polyurethane rubber Silicone brush Latex rubber Sheet metal or zinc Clay Casting plaster Lime Gel Fibres glass matt catalyst

Arches Lancet gothic Stilted semi circular Segmental Horseshoe Moorish Obtuse/Drop Gothic Equilateral Gothic Tudor Ogee False Elliptical True Elliptical Plasterers oval

Cornices In-situ Construct running mould Mark position of cornice on wall & ceiling Snap chalk lines on walls all round room Form screeds & put up running rules Muffle running mould Core out cornice Finish with lime putty & casting plaster

cornices Repairs Cut piece of mould & trace onto tin &cut out Run length of cornice on bench Cut out effected area Cut new length to size Secure cornice with screws or casting plaster Finish joints

Niches In-situ Construct the profile Muffle profile Position profile at centre of niche Core out niche Remove muffle Finish niche Run perimeter mould and plant

cornice Moulding members Ovolo; fillet; cyma-recta; cyma-recta; torus; scotia; cavito; drip member; weathering; throat

Order of Architecture Entablature Column Pedestal Cornice Capital Capital Frieze Shaft Die Architrave Base Base

Glass fibre moulds Apply bees wax to mould (4 coats) Apply gel coat with pigment +20% hardener Apply resin coat with filler + allow to stiffen Apply 2 nd coat of resin and filler Lay on the matt and brush well in with gel Trim edges and allow to cure

Pigment pastes Are mixed into gel coat to form colour of mould Are added to each coat to ensure totally covered

Glass fibre moulds Hazards Harmful to skin eyes &mouth Wear goggles, gloves, barrier cream, mask Do not inhale vapours Work in ventilated area Highly flamable catalyst resin should be disposed of carefully

Faults & Defects Chattering ; when a mould seems to jump and shudder Seaming; When P.V.C is poured too slowly the temperature drops and leaves seams in rubber this causes lines in finished mould

Columns Run collar screeds of correct size Cut collar screeds and fix to column Lay on floating coat Screed using collar screeds and straight edge Apply finish coat

PVC Moulds Comes in rubber cake like form Is cut up and melted in thermostat at 120 c to170 c case is set up around centre piece Allow 30mm around edges Centre piece is sealed Hot p.v.c can be poured over mould When set centre piece can be removed Multiple moulds can made from cast Rubber will melt at 180 c

Cold Pour Put centre piece on bench Set up fence around 30mm from edge and 30mm above highest point Treat model Mix compound and catalyst Pour and allow to set