Cov kua roj (silicone) rubbish yog khoom hauv cov thawv. Vim tias lawv tsis tshua pom kev, cov rubbers no tuaj yeem raug pumped los ntawm cov kav dej thiab cov hlua rau cov cuab yeej siv tawv. Ob qho khoom pumped los ntawm ib qho khoom siv hluav taws xob los ntawm lub ntsuas pa. Ib qho ntawm cov khoom muaj cov catalyst, feem ntau platinum raws li. Kev tha xim xim nrog rau lwm cov khoom ntxiv yuav ntxiv tau ua ntej cov khoom nkag hauv qhov chaw seem ntawm cov khoom seem. Nyob rau hauv qhov sib tov khoom zoo li qub cov khoom sib xyaw zoo thiab muab xa mus rau qhov chaw txias ntawm qhov kev txhaj tshuaj molding. Cov khoom cua zoo li qub ua ib homogeneous cov ntaub ntawv uas tshwm sim los ntawm cov khoom uas tsis zoo ib yam nkaus xwb, tab sis kuj los ntawm qhov chaw. Qhov no yog nyob rau hauv sib piv rau cov khoom siv roj hmab cov roj hmab uas muaj cov khoom ua ntej thiab cov khoom qub. Hauv kev sib piv, cov tshuaj nyhav nyuab heev yog ua los ntawm kev hloov molding thiab ua rau cov khoom siv tsis muaj zog thiab kev tswj, ua rau ntau qhov sib txawv. Tsis tas li ntawd, cov khoom siv roj silicone roj hmab yog ua kom sov dua thiab yuav tsum tau siv sij hawm ntev dua.
Ua kua dej ua kua muaj viscosity tsawg heev thiab yuav tsum tau zoo meej ntxhuav ntawm cov pwm kab noj hniav kom thiaj li lav tau cov khoom ua tiav tsis tiav. Raws li kev txhaj tshuaj yog ntsuas ntawm kev kub siab, hlau dilation thiab kev txav ntawm cov ntaub ntawv yuav tsum muab coj los tsim rau hauv tus qauv tsim ntawm LSR kev siv twj.