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timo na pravilno mesto. Na taj načinnećemo biti iznenađeni prilikomotvaranja kalupa (kod kalupaod silikona) i otkrivanja rupica iliudubljenja, te popravljanju tihgrešaka.2. Razmak između unutrašnjegi spoljašnjeg kalupaPrikom montiranja spoljašnjegkalupa, koji nameštamo poslemontaže unutrašneg, treba pazitina pravilan razmak izmeđunjih. Kad su u pitanju zakrivljenii tanji odlivci postoji veća mogućnostza dodir između kalupa.Kontrolisanje razmaka je kodprozirnoga kalupa jednostavno(slika 7 i 8). Na spoljašnji kaluppostavimo neproziran material(alu folija) i osvetlimo ga jakimizvorom svetlosti (džepna baterija).Na zidu unutrašnjeg kalupapojavi se senka i jasno je vidljivadistanca između spoljašnjog iunutrašneg kalupa. Ako apstrahujemodebljinu prozirnog kalupa(cca 0,4 mm), možemo da ocenimoda li će debljina odlivka bitiadekvatna. Pokretanjem alu folijena spoljašnjem kalupu možemobilo gde da proverimo da li je razmakpravilan. Sve vreme dok sespoljašnji kalup ne prilepi nastaklo možemo da korigujemomoguća odstupanja.3. Injektiranje i ulivanje smoleproblemi: levkovi, injektiranje,punjenje kalupaKod prozirnog kalupa skoroda ne dolazi u obzir upotreba levka,pošto u kalup koji je sa svihstrana zatvoren injekcijom ulivamosmolu. Umesto levka u kalupunapravimo dve rupice. Iglom jednostavnoprodremo u kalup i postavimoje tačno u ugao kalupa štoje ujedno i način da se u uglu izbegnezadržavanje vazduha (slika9). Problem sila koje nastaju prilikomistiskivanja smole iz injekcijenije tako veliki kao kod kalupaod silikona, jer je prozirni kalupčvršći i sile pritiska i potiska seraspoređuju na ceo kalup. Tako silenisu skoncentrisane samo najednom delu, kao kod kalupa odsilikonske gume. Kod punjenjakalupa smolom naginjanjempredmeta sprečavamo da se vazduhzarobi u uglu (slika 10 i 11).Bez bojazni da će se smola izliti izveć napunjenog kalupa, možemonastaviti i kod sledećeg kalupa,na istom predmetu. Rupice za iglui vazduh su naime tako male dapovršinski pritisak sprečava dasmola iscuri pri kratkotrajnomnaginjanju predmeta. Takav manevarbio bi teže izvodljiv kodupotrebe levka, jer bi smola od-15812. i 13. Nežnim kucanjem metalnom lopaticomza modeliranje tačno na mestu gde senalazi mehurić postižemo male vibracije kojesu jače od površinskog napona i na taj načinmehurić dovodimo do rupice za vazduh.Tapping on the plastic mould with a metalspatula to help the bubble to rise slowlytowards the air hole.14. Pričvršćivanje prozirnog kalupa na staklenipredmet.Fixing a transparent mould to a glass objectPričvršćivanje fragmenata na prozirni kalupkoji je ujedno nosilac unutrašnjeg oblika čaše.Fixing glass fragments to a transparent mould,which conforms to the entire inner configurationof the glass object and supports the fragmentsin their correct positions.2. Controlling the space betweeninner and outer mouldsAn outer mould is placed in positionon the glass after an innermould has already been placedthere. It is important to maintainthe correct distance between theinner and outer mould. If the gapin the glass is large and curved –especially in two directions, andthe glass itself is thin, it is quitepossible that the moulds will touchin several points. In the case of atransparent mould, it is quite simpleto control the distance betweenthe moulds. (Figs. 7 & 8). A piece ofnon-transparent material (aluminumfoil) is placed on the outermould and illuminated with a pockettorch. A shadow appears on theinner mould wall and the distancebetween the outer and inner mouldis clearly visible. If the thickness ofthe transparent mould (approximately0.4 cm) is ignored, it can beestimated whether the cast thicknesswill be suitable. By movingthe foil along, the correct distancebetween the moulds at any givenpoint, can be checked. As long asthe silicone rubber, used to secure atransparent mould to the glass hasnot fully cured, any possible irregularitycan be corrected.3. Filling moulds by injectingor casting epoxy resinWhen working with a transparentmould, I generally do not useany funnels as I usually inject resininto the mould that is closed fromall sides. Instead of using a funnel, Imake two small holes in the mould.I penetrate the mould with a needle,which I push precisely towards thecorner of a mould to prevent the airfrom getting trapped in the corner(Fig. 9). The forces released whenepoxy resin is squeezed from theinjection are not as great as in thecase of a silicone mould.That is becausea transparent mould is moresolid; pressure and pull forces arearranged along the entire mould andare not concentrated on only onepart as in the case of a silicone rubbermould. When filling the mouldwith resin, I hold the object sidewise,thus preventing the air from gettingtrapped in the angle (Figs. 10and 11). I can continue holding theobject sidewise when filling the nextmould on the same glass object withoutfear that resin will flow out ofthe already filled mould. The holefor a needle and air is so small thatthe surface pressure prevents resinfrom flowing out when the object isheld sidewise for a short period oftime. Such a manoeuvre would bemore difficult to carry out with fun-